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CVE-2023-20049
Vulnerability from cvelistv5
Published
2023-03-09 00:00
Modified
2024-10-28 16:33
Severity ?
EPSS score ?
Summary
A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads.
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| ▼ | Cisco | Cisco IOS XR Software |
Version: n/a |
|
|
|||
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cisco-sa-bfd-XmRescbT
Vulnerability from csaf_cisco
Published
2023-03-08 16:00
Modified
2023-03-08 16:00
Summary
Cisco IOS XR Software for ASR 9000 Series Routers Bidirectional Forwarding Detection Denial of Service Vulnerability
Notes
Summary
A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition.
This vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads.
Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"]/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"]
This advisory is part of the March 2023 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2023 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74917"].
Vulnerable Products
This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco IOS XR 64-bit Software and have BFD hardware offload enabled for any of the installed line cards:
ASR 9000 Series Aggregation Services Routers only if they have a Lightspeed or Lightspeed-Plus-based line card installed
ASR 9902 Compact High-Performance Routers
ASR 9903 Compact High-Performance Routers
For information about which Cisco software releases are vulnerable, see the Fixed Software ["#fs"] section of this advisory.
Determine Which Line Cards are Installed
To determine which line cards are installed in the device, use the show platform CLI command.
Cisco ASR 9902 and 9903 Compact High-Performance Routers integrate a Lightspeed-Plus-based line card.
The following line cards are Lightspeed-based:
A9K-16X100GE-TR
A99-16X100GE-X-SE
A99-32X100GE-TR
The following line cards are Lightspeed-Plus-based:
A9K-4HG-FLEX-SE
A9K-4HG-FLEX-TR
A9K-8HG-FLEX-SE
A9K-8HG-FLEX-TR
A9K-20HG-FLEX-SE
A9K-20HG-FLEX-TR
A99-4HG-FLEX-SE
A99-4HG-FLEX-TR
A99-10X400GE-X-SE
A99-10X400GE-X-TR
A99-32X100GE-X-SE
A99-32X100GE-X-TR
For more information about line card type identification, see ASR 9000 Series Line Card Types ["https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html"].
Note: The Cisco Lightspeed-Plus list of product identifiers was accurate at the time of publication. For specific questions and further clarification about a product identifier, contact the Cisco Technical Assistance Center (TAC).
Determine Whether BFD Hardware Offload is Enabled
To determine which line cards have BFD hardware offload enabled, use the show bfd hw-offload state CLI command. If the configuration and operational states are enabled on one of the previously mentioned line cards, the device is affected by this vulnerability. The following example shows a device in which BFD hardware offload is not enabled:
RP/0/RSP0/CPU0:ASR9006#show bfd hw-offload state
Wed Mar 8 16:00:00.000 UTC BFD HW OFFLOAD Feature state: 0/2/CPU0 ----------------- Configuration State: Disabled Operational State: Disabled RP/0/RSP0/CPU0:ASR9006#
The following example shows a device in which BFD hardware offload is enabled:
RP/0/RSP0/CPU0:ASR9006#show bfd hw-offload state
Wed Mar 8 16:00:00.000 UTC BFD HW OFFLOAD Feature state: 0/2/CPU0 ----------------- Configuration State: Enabled Operational State: Enabled RP/0/RSP0/CPU0:ASR9006#
Not all BFD sessions are handled in hardware even if BFD hardware offload is enabled. At least one BFD session has to indicate H/W as Yes, as shown in the following example:
RP/0/RSP0/CPU0:ASR9006#show bfd all session
Wed Mar 8 16:00:00.000 UTC IPv4: ----- Interface Dest Addr Local det time(int*mult) State
Echo Async H/W NPU ---------- ------------- ------------ ---------------- ---------- ti100 10.0.0.1 0s(0s*0) 900ms(300ms*3) UP
No n/a
Hu0/2/0/15 192.168.100.100 0s(0s*0) 900ms(300ms*3) UP
Yes 0/2/CPU0 RP/0/RSP0/CPU0:ASR9006#
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp"] section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following Cisco products:
IOS Software
IOS XE Software
IOS XR Platforms not listed in the Vulnerable Products ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp"] section of this advisory
NX-OS Software
Details
This vulnerability cannot be exploited with IPv6 BFD packets. However, if an IPv6 BFD session also has an IPv4 address configured on the attached interface, an attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to the configured IPv4 address on the interface. If interface Te0/1/0/10/0 was also configured with IPv4 address 192.168.1.1, the attacker could exploit the IPv6 BFD session by sending a crafted IPv4 BFD packet to 192.168.1.1, as shown in the following example:
RP/0/RSP0/CPU0:ASR9006#show bfd all session
Wed Mar 8 16:00:00.000 UT IPv4: ----- IPv6: ----- Interface Dest Addr Local det time(int*mult) State H/W NPU Echo Async ------------------- --------------- ---------------- ---------------- ---------- Te0/1/0/10/0 fe80::36f8:e7ff:fee0:947 Yes 0/1/CPU0 0s(0s*0) 900ms(300ms*3) UP
Workarounds
There is a workaround and a mitigation that address this vulnerability.
The only workaround that fully mitigates this vulnerability is disabling BFD hardware offload. Creating Infrastructure Access Control Lists (iACLs) is a mitigation that only limits the attack surface.
Disable BFD Hardware Offload
To disable BFD hardware offload, remove any of the hw-module bfw-hw-offload enable commands and reset the assigned line card, as shown in the following example:
RP/0/RSP0/CPU0:ASR9006#config terminal
Wed Mar 8 16:00:00.000 UTC
RP/0/RSP0/CPU0:ASR9006(config)#no hw-module bfd-hw-offload enable location 0/2/CPU0
RP/0/RSP0/CPU0:ASR9006(config)#commit
RP/0/RSP0/CPU0:ASR9006(config)#end
RP/0/RSP0/CPU0:ASR9006#hw-module subslot 0/2/CPU0 reload
Create Infrastructure Access Control Lists
While iACLs limit the attack surface, they do not prevent exploitation from allowed peers and are subject to spoofing.
The following example shows an iACL that allows only infrastructure BFD peers (where 192.0.2.x/24 is the infrastructure address space):
RP/0/RSP0/CPU0:ASR9006# show running-config ipv4 access-list
ipv4 access-list BFD_DROP
5 remark * Mark sure to Allow Legitimate BFD peers *
10 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq bfd
11 remark * Depending on BFD deployment may need *
12 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq 4784
13 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq 6784
15 remark * Drop all other attempts to the infrastructure address space *
20 deny udp any 192.0.2.0 0.0.0.255 eq bfd
30 permit ipv4 any any
!
RP/0/RSP0/CPU0:ASR9006#
Apply this iACL to all exposed interfaces.
The following example shows an iACL that allows only BFD packets with a Time to Live (TTL) of 255 (expected for single hop sessions):
RP/0/RSP0/CPU0:ASR9006# show running-config ipv4 access-list
ipv4 access-list BFD_DROP_TTL
5 remark * Drop based purely on TTL. Allow our Single Hop BFD sessions *
10 permit udp any 192.0.2.0 0.0.0.255 eq bfd ttl eq 255
11 remark * Depending on BFD deployment may need *
12 permit udp any 192.0.2.0 0.0.0.255 eq 4784 ttl eq 255
13 permit udp any 192.0.2.0 0.0.0.255 eq 6784 ttl eq 255
14 remark * You would need to tune the above two lines for multi-hop sessions *
15 remark * Deny anything else for BFD *
20 deny udp any any eq bfd ttl lt 255
21 remark * You would need to tune the above line for multi-hop sessions *
30 permit ipv4 any any
!
RP/0/RSP0/CPU0:ASR9006#
Apply this iACL to all exposed interfaces.
While this workaround and mitigation have been deployed and were proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.
Fixed Software
Cisco has released free software updates ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#ssu"] that address the vulnerability described in this advisory. Customers with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.
Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.html ["https://www.cisco.com/c/en/us/products/end-user-license-agreement.html"]
Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
The Cisco Support and Downloads page ["https://www.cisco.com/c/en/us/support/index.html"] on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.
When considering software upgrades ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"], customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page ["https://www.cisco.com/go/psirt"], to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html ["https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"]
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
In the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"] as indicated in this section.
Cisco IOS XR Software Release First Fixed Release 6.5 Migrate to a fixed release. 6.6 Migrate to a fixed release. 7.0 Migrate to a fixed release. 7.1 Migrate to a fixed release. 7.3 Migrate to a fixed release. 7.4 Migrate to a fixed release. 7.5 7.5.3 7.6 7.6.2 7.7 and later 7.7.1
Cisco has released the following SMUs to address this vulnerability.
Note: Customers who require SMUs for releases that are not listed in the following table are advised to contact their support organization.
Cisco IOS XR Software Release Platform SMU Name 7.1.3 ASR9K-X64 asr9k-x64-7.1.3.CSCwc39336 7.3.2 ASR9K-X64 asr9k-x64-7.3.2.CSCwc39336 7.5.2 ASR9K-X64 asr9k-x64-7.5.2.CSCwc39336
The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
Vulnerability Policy
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy ["http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"]. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
Exploitation and Public Announcements
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
Source
This vulnerability was found during the resolution of a Cisco TAC support case.
Legal Disclaimer
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products.
{
"document": {
"acknowledgments": [
{
"summary": "This vulnerability was found during the resolution of a Cisco TAC support case."
}
],
"category": "csaf_security_advisory",
"csaf_version": "2.0",
"notes": [
{
"category": "summary",
"text": "A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads.\r\n\r\nCisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.\r\n\r\nThis advisory is available at the following link:\r\nhttps://sec.cloudapps.cisco.com [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT\"]/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT\"]\r\n\r\nThis advisory is part of the March 2023 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2023 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication [\"https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74917\"].",
"title": "Summary"
},
{
"category": "general",
"text": "This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco IOS XR 64-bit Software and have BFD hardware offload enabled for any of the installed line cards:\r\n\r\nASR 9000 Series Aggregation Services Routers only if they have a Lightspeed or Lightspeed-Plus-based line card installed\r\nASR 9902 Compact High-Performance Routers\r\nASR 9903 Compact High-Performance Routers\r\n\r\nFor information about which Cisco software releases are vulnerable, see the Fixed Software [\"#fs\"] section of this advisory.\r\n Determine Which Line Cards are Installed\r\nTo determine which line cards are installed in the device, use the show platform CLI command.\r\n\r\nCisco ASR 9902 and 9903 Compact High-Performance Routers integrate a Lightspeed-Plus-based line card.\r\n\r\nThe following line cards are Lightspeed-based:\r\n\r\nA9K-16X100GE-TR\r\nA99-16X100GE-X-SE\r\nA99-32X100GE-TR\r\n\r\nThe following line cards are Lightspeed-Plus-based:\r\n\r\nA9K-4HG-FLEX-SE\r\nA9K-4HG-FLEX-TR\r\nA9K-8HG-FLEX-SE\r\nA9K-8HG-FLEX-TR\r\nA9K-20HG-FLEX-SE\r\nA9K-20HG-FLEX-TR\r\nA99-4HG-FLEX-SE\r\nA99-4HG-FLEX-TR\r\nA99-10X400GE-X-SE\r\nA99-10X400GE-X-TR\r\nA99-32X100GE-X-SE\r\nA99-32X100GE-X-TR\r\n\r\nFor more information about line card type identification, see ASR 9000 Series Line Card Types [\"https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html\"].\r\n\r\nNote: The Cisco Lightspeed-Plus list of product identifiers was accurate at the time of publication. For specific questions and further clarification about a product identifier, contact the Cisco Technical Assistance Center (TAC).\r\n Determine Whether BFD Hardware Offload is Enabled\r\nTo determine which line cards have BFD hardware offload enabled, use the show bfd hw-offload state CLI command. If the configuration and operational states are enabled on one of the previously mentioned line cards, the device is affected by this vulnerability. The following example shows a device in which BFD hardware offload is not enabled:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#show bfd hw-offload state\r\nWed Mar 8 16:00:00.000 UTC BFD HW OFFLOAD Feature state: 0/2/CPU0 ----------------- Configuration State: Disabled Operational State: Disabled RP/0/RSP0/CPU0:ASR9006#\r\n\r\nThe following example shows a device in which BFD hardware offload is enabled:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#show bfd hw-offload state\r\nWed Mar 8 16:00:00.000 UTC BFD HW OFFLOAD Feature state: 0/2/CPU0 ----------------- Configuration State: Enabled Operational State: Enabled RP/0/RSP0/CPU0:ASR9006#\r\n\r\nNot all BFD sessions are handled in hardware even if BFD hardware offload is enabled. At least one BFD session has to indicate H/W as Yes, as shown in the following example:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#show bfd all session\r\nWed Mar 8 16:00:00.000 UTC IPv4: ----- Interface Dest Addr Local det time(int*mult) State\r\nEcho Async H/W NPU ---------- ------------- ------------ ---------------- ---------- ti100 10.0.0.1 0s(0s*0) 900ms(300ms*3) UP\r\nNo n/a\r\nHu0/2/0/15 192.168.100.100 0s(0s*0) 900ms(300ms*3) UP\r\nYes 0/2/CPU0 RP/0/RSP0/CPU0:ASR9006#",
"title": "Vulnerable Products"
},
{
"category": "general",
"text": "Only products listed in the Vulnerable Products [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp\"] section of this advisory are known to be affected by this vulnerability.\r\n\r\nCisco has confirmed that this vulnerability does not affect the following Cisco products:\r\n\r\nIOS Software\r\nIOS XE Software\r\nIOS XR Platforms not listed in the Vulnerable Products [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp\"] section of this advisory\r\nNX-OS Software",
"title": "Products Confirmed Not Vulnerable"
},
{
"category": "general",
"text": "This vulnerability cannot be exploited with IPv6 BFD packets. However, if an IPv6 BFD session also has an IPv4 address configured on the attached interface, an attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to the configured IPv4 address on the interface. If interface Te0/1/0/10/0 was also configured with IPv4 address 192.168.1.1, the attacker could exploit the IPv6 BFD session by sending a crafted IPv4 BFD packet to 192.168.1.1, as shown in the following example:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#show bfd all session\r\nWed Mar 8 16:00:00.000 UT IPv4: ----- IPv6: ----- Interface Dest Addr Local det time(int*mult) State H/W NPU Echo Async ------------------- --------------- ---------------- ---------------- ---------- Te0/1/0/10/0 fe80::36f8:e7ff:fee0:947 Yes 0/1/CPU0 0s(0s*0) 900ms(300ms*3) UP",
"title": "Details"
},
{
"category": "general",
"text": "There is a workaround and a mitigation that address this vulnerability.\r\n\r\nThe only workaround that fully mitigates this vulnerability is disabling BFD hardware offload. Creating Infrastructure Access Control Lists (iACLs) is a mitigation that only limits the attack surface.\r\n\r\nDisable BFD Hardware Offload\r\n\r\nTo disable BFD hardware offload, remove any of the hw-module bfw-hw-offload enable commands and reset the assigned line card, as shown in the following example:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#config terminal\r\nWed Mar 8 16:00:00.000 UTC\r\nRP/0/RSP0/CPU0:ASR9006(config)#no hw-module bfd-hw-offload enable location 0/2/CPU0\r\nRP/0/RSP0/CPU0:ASR9006(config)#commit\r\nRP/0/RSP0/CPU0:ASR9006(config)#end\r\nRP/0/RSP0/CPU0:ASR9006#hw-module subslot 0/2/CPU0 reload\r\n\r\n\r\nCreate Infrastructure Access Control Lists\r\n\r\nWhile iACLs limit the attack surface, they do not prevent exploitation from allowed peers and are subject to spoofing.\r\n\r\nThe following example shows an iACL that allows only infrastructure BFD peers (where 192.0.2.x/24 is the infrastructure address space):\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006# show running-config ipv4 access-list\r\nipv4 access-list BFD_DROP\r\n5 remark * Mark sure to Allow Legitimate BFD peers *\r\n 10 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq bfd\r\n11 remark * Depending on BFD deployment may need *\r\n12 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq 4784\r\n 13 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq 6784\r\n15 remark * Drop all other attempts to the infrastructure address space *\r\n 20 deny udp any 192.0.2.0 0.0.0.255 eq bfd\r\n 30 permit ipv4 any any\r\n!\r\nRP/0/RSP0/CPU0:ASR9006#\r\n\r\nApply this iACL to all exposed interfaces.\r\n\r\nThe following example shows an iACL that allows only BFD packets with a Time to Live (TTL) of 255 (expected for single hop sessions):\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006# show running-config ipv4 access-list\r\nipv4 access-list BFD_DROP_TTL\r\n5 remark * Drop based purely on TTL. Allow our Single Hop BFD sessions *\r\n10 permit udp any 192.0.2.0 0.0.0.255 eq bfd ttl eq 255\r\n11 remark * Depending on BFD deployment may need *\r\n12 permit udp any 192.0.2.0 0.0.0.255 eq 4784 ttl eq 255\r\n13 permit udp any 192.0.2.0 0.0.0.255 eq 6784 ttl eq 255\r\n14 remark * You would need to tune the above two lines for multi-hop sessions *\r\n15 remark * Deny anything else for BFD *\r\n20 deny udp any any eq bfd ttl lt 255\r\n21 remark * You would need to tune the above line for multi-hop sessions *\r\n30 permit ipv4 any any\r\n!\r\nRP/0/RSP0/CPU0:ASR9006#\r\n\r\nApply this iACL to all exposed interfaces.\r\n\r\nWhile this workaround and mitigation have been deployed and were proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.",
"title": "Workarounds"
},
{
"category": "general",
"text": "Cisco has released free software updates [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#ssu\"] that address the vulnerability described in this advisory. Customers with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.\r\n\r\nCustomers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:\r\nhttps://www.cisco.com/c/en/us/products/end-user-license-agreement.html [\"https://www.cisco.com/c/en/us/products/end-user-license-agreement.html\"]\r\n\r\nAdditionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.\r\n\r\nThe Cisco Support and Downloads page [\"https://www.cisco.com/c/en/us/support/index.html\"] on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.\r\n\r\nWhen considering software upgrades [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"], customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page [\"https://www.cisco.com/go/psirt\"], to determine exposure and a complete upgrade solution.\r\n\r\nIn all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.\r\n Customers Without Service Contracts\r\nCustomers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html [\"https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html\"]\r\n\r\nCustomers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.\r\n Fixed Releases\r\nIn the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"] as indicated in this section.\r\n Cisco IOS XR Software Release First Fixed Release 6.5 Migrate to a fixed release. 6.6 Migrate to a fixed release. 7.0 Migrate to a fixed release. 7.1 Migrate to a fixed release. 7.3 Migrate to a fixed release. 7.4 Migrate to a fixed release. 7.5 7.5.3 7.6 7.6.2 7.7 and later 7.7.1\r\nCisco has released the following SMUs to address this vulnerability.\r\n\r\nNote: Customers who require SMUs for releases that are not listed in the following table are advised to contact their support organization.\r\n Cisco IOS XR Software Release Platform SMU Name 7.1.3 ASR9K-X64 asr9k-x64-7.1.3.CSCwc39336 7.3.2 ASR9K-X64 asr9k-x64-7.3.2.CSCwc39336 7.5.2 ASR9K-X64 asr9k-x64-7.5.2.CSCwc39336\r\nThe Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.",
"title": "Fixed Software"
},
{
"category": "general",
"text": "To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy [\"http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html\"]. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.",
"title": "Vulnerability Policy"
},
{
"category": "general",
"text": "The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.",
"title": "Exploitation and Public Announcements"
},
{
"category": "general",
"text": "This vulnerability was found during the resolution of a Cisco TAC support case.",
"title": "Source"
},
{
"category": "legal_disclaimer",
"text": "THIS DOCUMENT IS PROVIDED ON AN \"AS IS\" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.\r\n\r\nA standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products.",
"title": "Legal Disclaimer"
}
],
"publisher": {
"category": "vendor",
"contact_details": "psirt@cisco.com",
"issuing_authority": "Cisco PSIRT",
"name": "Cisco",
"namespace": "https://wwww.cisco.com"
},
"references": [
{
"category": "self",
"summary": "Cisco IOS XR Software for ASR 9000 Series Routers Bidirectional Forwarding Detection Denial of Service Vulnerability",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"
},
{
"category": "external",
"summary": "Cisco Event Response: March 2023 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication",
"url": "https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74917"
},
{
"category": "external",
"summary": "Cisco Security Vulnerability Policy",
"url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
},
{
"category": "external",
"summary": "ASR 9000 Series Line Card Types",
"url": "https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html"
},
{
"category": "external",
"summary": "Vulnerable Products",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp"
},
{
"category": "external",
"summary": "free software updates",
"url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#ssu"
},
{
"category": "external",
"summary": "https://www.cisco.com/c/en/us/products/end-user-license-agreement.html",
"url": "https://www.cisco.com/c/en/us/products/end-user-license-agreement.html"
},
{
"category": "external",
"summary": "Cisco\u0026nbsp;Support and Downloads page",
"url": "https://www.cisco.com/c/en/us/support/index.html"
},
{
"category": "external",
"summary": "considering software upgrades",
"url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"
},
{
"category": "external",
"summary": "Cisco\u0026nbsp;Security Advisories page",
"url": "https://www.cisco.com/go/psirt"
},
{
"category": "external",
"summary": "https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html",
"url": "https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"
},
{
"category": "external",
"summary": "Security Vulnerability Policy",
"url": "http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"
}
],
"title": "Cisco IOS XR Software for ASR 9000 Series Routers Bidirectional Forwarding Detection Denial of Service Vulnerability",
"tracking": {
"current_release_date": "2023-03-08T16:00:00+00:00",
"generator": {
"date": "2024-05-10T23:22:28+00:00",
"engine": {
"name": "TVCE"
}
},
"id": "cisco-sa-bfd-XmRescbT",
"initial_release_date": "2023-03-08T16:00:00+00:00",
"revision_history": [
{
"date": "2023-03-08T15:32:01+00:00",
"number": "1.0.0",
"summary": "Initial public release."
}
],
"status": "final",
"version": "1.0.0"
}
},
"product_tree": {
"branches": [
{
"branches": [
{
"category": "product_family",
"name": "Cisco IOS XR Software",
"product": {
"name": "Cisco IOS XR Software ",
"product_id": "CSAFPID-5834"
}
}
],
"category": "vendor",
"name": "Cisco"
}
]
},
"vulnerabilities": [
{
"cve": "CVE-2023-20049",
"ids": [
{
"system_name": "Cisco Bug ID",
"text": "CSCwc39336"
}
],
"notes": [
{
"category": "other",
"text": "Complete.",
"title": "Affected Product Comprehensiveness"
}
],
"product_status": {
"known_affected": [
"CSAFPID-5834"
]
},
"release_date": "2023-03-08T16:00:00+00:00",
"remediations": [
{
"category": "vendor_fix",
"details": "Cisco has released software updates that address this vulnerability.",
"product_ids": [
"CSAFPID-5834"
],
"url": "https://software.cisco.com"
}
],
"scores": [
{
"cvss_v3": {
"baseScore": 8.6,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
"version": "3.1"
},
"products": [
"CSAFPID-5834"
]
}
],
"title": "Cisco IOS XR Software for ASR 9000 Series Routers BFD Denial of Service Vulnerability"
}
]
}
cisco-sa-bfd-xmrescbt
Vulnerability from csaf_cisco
Published
2023-03-08 16:00
Modified
2023-03-08 16:00
Summary
Cisco IOS XR Software for ASR 9000 Series Routers Bidirectional Forwarding Detection Denial of Service Vulnerability
Notes
Summary
A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition.
This vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads.
Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"]/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"]
This advisory is part of the March 2023 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2023 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74917"].
Vulnerable Products
This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco IOS XR 64-bit Software and have BFD hardware offload enabled for any of the installed line cards:
ASR 9000 Series Aggregation Services Routers only if they have a Lightspeed or Lightspeed-Plus-based line card installed
ASR 9902 Compact High-Performance Routers
ASR 9903 Compact High-Performance Routers
For information about which Cisco software releases are vulnerable, see the Fixed Software ["#fs"] section of this advisory.
Determine Which Line Cards are Installed
To determine which line cards are installed in the device, use the show platform CLI command.
Cisco ASR 9902 and 9903 Compact High-Performance Routers integrate a Lightspeed-Plus-based line card.
The following line cards are Lightspeed-based:
A9K-16X100GE-TR
A99-16X100GE-X-SE
A99-32X100GE-TR
The following line cards are Lightspeed-Plus-based:
A9K-4HG-FLEX-SE
A9K-4HG-FLEX-TR
A9K-8HG-FLEX-SE
A9K-8HG-FLEX-TR
A9K-20HG-FLEX-SE
A9K-20HG-FLEX-TR
A99-4HG-FLEX-SE
A99-4HG-FLEX-TR
A99-10X400GE-X-SE
A99-10X400GE-X-TR
A99-32X100GE-X-SE
A99-32X100GE-X-TR
For more information about line card type identification, see ASR 9000 Series Line Card Types ["https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html"].
Note: The Cisco Lightspeed-Plus list of product identifiers was accurate at the time of publication. For specific questions and further clarification about a product identifier, contact the Cisco Technical Assistance Center (TAC).
Determine Whether BFD Hardware Offload is Enabled
To determine which line cards have BFD hardware offload enabled, use the show bfd hw-offload state CLI command. If the configuration and operational states are enabled on one of the previously mentioned line cards, the device is affected by this vulnerability. The following example shows a device in which BFD hardware offload is not enabled:
RP/0/RSP0/CPU0:ASR9006#show bfd hw-offload state
Wed Mar 8 16:00:00.000 UTC BFD HW OFFLOAD Feature state: 0/2/CPU0 ----------------- Configuration State: Disabled Operational State: Disabled RP/0/RSP0/CPU0:ASR9006#
The following example shows a device in which BFD hardware offload is enabled:
RP/0/RSP0/CPU0:ASR9006#show bfd hw-offload state
Wed Mar 8 16:00:00.000 UTC BFD HW OFFLOAD Feature state: 0/2/CPU0 ----------------- Configuration State: Enabled Operational State: Enabled RP/0/RSP0/CPU0:ASR9006#
Not all BFD sessions are handled in hardware even if BFD hardware offload is enabled. At least one BFD session has to indicate H/W as Yes, as shown in the following example:
RP/0/RSP0/CPU0:ASR9006#show bfd all session
Wed Mar 8 16:00:00.000 UTC IPv4: ----- Interface Dest Addr Local det time(int*mult) State
Echo Async H/W NPU ---------- ------------- ------------ ---------------- ---------- ti100 10.0.0.1 0s(0s*0) 900ms(300ms*3) UP
No n/a
Hu0/2/0/15 192.168.100.100 0s(0s*0) 900ms(300ms*3) UP
Yes 0/2/CPU0 RP/0/RSP0/CPU0:ASR9006#
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp"] section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following Cisco products:
IOS Software
IOS XE Software
IOS XR Platforms not listed in the Vulnerable Products ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp"] section of this advisory
NX-OS Software
Details
This vulnerability cannot be exploited with IPv6 BFD packets. However, if an IPv6 BFD session also has an IPv4 address configured on the attached interface, an attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to the configured IPv4 address on the interface. If interface Te0/1/0/10/0 was also configured with IPv4 address 192.168.1.1, the attacker could exploit the IPv6 BFD session by sending a crafted IPv4 BFD packet to 192.168.1.1, as shown in the following example:
RP/0/RSP0/CPU0:ASR9006#show bfd all session
Wed Mar 8 16:00:00.000 UT IPv4: ----- IPv6: ----- Interface Dest Addr Local det time(int*mult) State H/W NPU Echo Async ------------------- --------------- ---------------- ---------------- ---------- Te0/1/0/10/0 fe80::36f8:e7ff:fee0:947 Yes 0/1/CPU0 0s(0s*0) 900ms(300ms*3) UP
Workarounds
There is a workaround and a mitigation that address this vulnerability.
The only workaround that fully mitigates this vulnerability is disabling BFD hardware offload. Creating Infrastructure Access Control Lists (iACLs) is a mitigation that only limits the attack surface.
Disable BFD Hardware Offload
To disable BFD hardware offload, remove any of the hw-module bfw-hw-offload enable commands and reset the assigned line card, as shown in the following example:
RP/0/RSP0/CPU0:ASR9006#config terminal
Wed Mar 8 16:00:00.000 UTC
RP/0/RSP0/CPU0:ASR9006(config)#no hw-module bfd-hw-offload enable location 0/2/CPU0
RP/0/RSP0/CPU0:ASR9006(config)#commit
RP/0/RSP0/CPU0:ASR9006(config)#end
RP/0/RSP0/CPU0:ASR9006#hw-module subslot 0/2/CPU0 reload
Create Infrastructure Access Control Lists
While iACLs limit the attack surface, they do not prevent exploitation from allowed peers and are subject to spoofing.
The following example shows an iACL that allows only infrastructure BFD peers (where 192.0.2.x/24 is the infrastructure address space):
RP/0/RSP0/CPU0:ASR9006# show running-config ipv4 access-list
ipv4 access-list BFD_DROP
5 remark * Mark sure to Allow Legitimate BFD peers *
10 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq bfd
11 remark * Depending on BFD deployment may need *
12 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq 4784
13 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq 6784
15 remark * Drop all other attempts to the infrastructure address space *
20 deny udp any 192.0.2.0 0.0.0.255 eq bfd
30 permit ipv4 any any
!
RP/0/RSP0/CPU0:ASR9006#
Apply this iACL to all exposed interfaces.
The following example shows an iACL that allows only BFD packets with a Time to Live (TTL) of 255 (expected for single hop sessions):
RP/0/RSP0/CPU0:ASR9006# show running-config ipv4 access-list
ipv4 access-list BFD_DROP_TTL
5 remark * Drop based purely on TTL. Allow our Single Hop BFD sessions *
10 permit udp any 192.0.2.0 0.0.0.255 eq bfd ttl eq 255
11 remark * Depending on BFD deployment may need *
12 permit udp any 192.0.2.0 0.0.0.255 eq 4784 ttl eq 255
13 permit udp any 192.0.2.0 0.0.0.255 eq 6784 ttl eq 255
14 remark * You would need to tune the above two lines for multi-hop sessions *
15 remark * Deny anything else for BFD *
20 deny udp any any eq bfd ttl lt 255
21 remark * You would need to tune the above line for multi-hop sessions *
30 permit ipv4 any any
!
RP/0/RSP0/CPU0:ASR9006#
Apply this iACL to all exposed interfaces.
While this workaround and mitigation have been deployed and were proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.
Fixed Software
Cisco has released free software updates ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#ssu"] that address the vulnerability described in this advisory. Customers with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.
Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.html ["https://www.cisco.com/c/en/us/products/end-user-license-agreement.html"]
Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
The Cisco Support and Downloads page ["https://www.cisco.com/c/en/us/support/index.html"] on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.
When considering software upgrades ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"], customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page ["https://www.cisco.com/go/psirt"], to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html ["https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"]
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
In the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"] as indicated in this section.
Cisco IOS XR Software Release First Fixed Release 6.5 Migrate to a fixed release. 6.6 Migrate to a fixed release. 7.0 Migrate to a fixed release. 7.1 Migrate to a fixed release. 7.3 Migrate to a fixed release. 7.4 Migrate to a fixed release. 7.5 7.5.3 7.6 7.6.2 7.7 and later 7.7.1
Cisco has released the following SMUs to address this vulnerability.
Note: Customers who require SMUs for releases that are not listed in the following table are advised to contact their support organization.
Cisco IOS XR Software Release Platform SMU Name 7.1.3 ASR9K-X64 asr9k-x64-7.1.3.CSCwc39336 7.3.2 ASR9K-X64 asr9k-x64-7.3.2.CSCwc39336 7.5.2 ASR9K-X64 asr9k-x64-7.5.2.CSCwc39336
The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
Vulnerability Policy
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy ["http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"]. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
Exploitation and Public Announcements
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
Source
This vulnerability was found during the resolution of a Cisco TAC support case.
Legal Disclaimer
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products.
{
"document": {
"acknowledgments": [
{
"summary": "This vulnerability was found during the resolution of a Cisco TAC support case."
}
],
"category": "csaf_security_advisory",
"csaf_version": "2.0",
"notes": [
{
"category": "summary",
"text": "A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads.\r\n\r\nCisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.\r\n\r\nThis advisory is available at the following link:\r\nhttps://sec.cloudapps.cisco.com [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT\"]/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT\"]\r\n\r\nThis advisory is part of the March 2023 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2023 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication [\"https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74917\"].",
"title": "Summary"
},
{
"category": "general",
"text": "This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco IOS XR 64-bit Software and have BFD hardware offload enabled for any of the installed line cards:\r\n\r\nASR 9000 Series Aggregation Services Routers only if they have a Lightspeed or Lightspeed-Plus-based line card installed\r\nASR 9902 Compact High-Performance Routers\r\nASR 9903 Compact High-Performance Routers\r\n\r\nFor information about which Cisco software releases are vulnerable, see the Fixed Software [\"#fs\"] section of this advisory.\r\n Determine Which Line Cards are Installed\r\nTo determine which line cards are installed in the device, use the show platform CLI command.\r\n\r\nCisco ASR 9902 and 9903 Compact High-Performance Routers integrate a Lightspeed-Plus-based line card.\r\n\r\nThe following line cards are Lightspeed-based:\r\n\r\nA9K-16X100GE-TR\r\nA99-16X100GE-X-SE\r\nA99-32X100GE-TR\r\n\r\nThe following line cards are Lightspeed-Plus-based:\r\n\r\nA9K-4HG-FLEX-SE\r\nA9K-4HG-FLEX-TR\r\nA9K-8HG-FLEX-SE\r\nA9K-8HG-FLEX-TR\r\nA9K-20HG-FLEX-SE\r\nA9K-20HG-FLEX-TR\r\nA99-4HG-FLEX-SE\r\nA99-4HG-FLEX-TR\r\nA99-10X400GE-X-SE\r\nA99-10X400GE-X-TR\r\nA99-32X100GE-X-SE\r\nA99-32X100GE-X-TR\r\n\r\nFor more information about line card type identification, see ASR 9000 Series Line Card Types [\"https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html\"].\r\n\r\nNote: The Cisco Lightspeed-Plus list of product identifiers was accurate at the time of publication. For specific questions and further clarification about a product identifier, contact the Cisco Technical Assistance Center (TAC).\r\n Determine Whether BFD Hardware Offload is Enabled\r\nTo determine which line cards have BFD hardware offload enabled, use the show bfd hw-offload state CLI command. If the configuration and operational states are enabled on one of the previously mentioned line cards, the device is affected by this vulnerability. The following example shows a device in which BFD hardware offload is not enabled:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#show bfd hw-offload state\r\nWed Mar 8 16:00:00.000 UTC BFD HW OFFLOAD Feature state: 0/2/CPU0 ----------------- Configuration State: Disabled Operational State: Disabled RP/0/RSP0/CPU0:ASR9006#\r\n\r\nThe following example shows a device in which BFD hardware offload is enabled:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#show bfd hw-offload state\r\nWed Mar 8 16:00:00.000 UTC BFD HW OFFLOAD Feature state: 0/2/CPU0 ----------------- Configuration State: Enabled Operational State: Enabled RP/0/RSP0/CPU0:ASR9006#\r\n\r\nNot all BFD sessions are handled in hardware even if BFD hardware offload is enabled. At least one BFD session has to indicate H/W as Yes, as shown in the following example:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#show bfd all session\r\nWed Mar 8 16:00:00.000 UTC IPv4: ----- Interface Dest Addr Local det time(int*mult) State\r\nEcho Async H/W NPU ---------- ------------- ------------ ---------------- ---------- ti100 10.0.0.1 0s(0s*0) 900ms(300ms*3) UP\r\nNo n/a\r\nHu0/2/0/15 192.168.100.100 0s(0s*0) 900ms(300ms*3) UP\r\nYes 0/2/CPU0 RP/0/RSP0/CPU0:ASR9006#",
"title": "Vulnerable Products"
},
{
"category": "general",
"text": "Only products listed in the Vulnerable Products [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp\"] section of this advisory are known to be affected by this vulnerability.\r\n\r\nCisco has confirmed that this vulnerability does not affect the following Cisco products:\r\n\r\nIOS Software\r\nIOS XE Software\r\nIOS XR Platforms not listed in the Vulnerable Products [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp\"] section of this advisory\r\nNX-OS Software",
"title": "Products Confirmed Not Vulnerable"
},
{
"category": "general",
"text": "This vulnerability cannot be exploited with IPv6 BFD packets. However, if an IPv6 BFD session also has an IPv4 address configured on the attached interface, an attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to the configured IPv4 address on the interface. If interface Te0/1/0/10/0 was also configured with IPv4 address 192.168.1.1, the attacker could exploit the IPv6 BFD session by sending a crafted IPv4 BFD packet to 192.168.1.1, as shown in the following example:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#show bfd all session\r\nWed Mar 8 16:00:00.000 UT IPv4: ----- IPv6: ----- Interface Dest Addr Local det time(int*mult) State H/W NPU Echo Async ------------------- --------------- ---------------- ---------------- ---------- Te0/1/0/10/0 fe80::36f8:e7ff:fee0:947 Yes 0/1/CPU0 0s(0s*0) 900ms(300ms*3) UP",
"title": "Details"
},
{
"category": "general",
"text": "There is a workaround and a mitigation that address this vulnerability.\r\n\r\nThe only workaround that fully mitigates this vulnerability is disabling BFD hardware offload. Creating Infrastructure Access Control Lists (iACLs) is a mitigation that only limits the attack surface.\r\n\r\nDisable BFD Hardware Offload\r\n\r\nTo disable BFD hardware offload, remove any of the hw-module bfw-hw-offload enable commands and reset the assigned line card, as shown in the following example:\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006#config terminal\r\nWed Mar 8 16:00:00.000 UTC\r\nRP/0/RSP0/CPU0:ASR9006(config)#no hw-module bfd-hw-offload enable location 0/2/CPU0\r\nRP/0/RSP0/CPU0:ASR9006(config)#commit\r\nRP/0/RSP0/CPU0:ASR9006(config)#end\r\nRP/0/RSP0/CPU0:ASR9006#hw-module subslot 0/2/CPU0 reload\r\n\r\n\r\nCreate Infrastructure Access Control Lists\r\n\r\nWhile iACLs limit the attack surface, they do not prevent exploitation from allowed peers and are subject to spoofing.\r\n\r\nThe following example shows an iACL that allows only infrastructure BFD peers (where 192.0.2.x/24 is the infrastructure address space):\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006# show running-config ipv4 access-list\r\nipv4 access-list BFD_DROP\r\n5 remark * Mark sure to Allow Legitimate BFD peers *\r\n 10 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq bfd\r\n11 remark * Depending on BFD deployment may need *\r\n12 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq 4784\r\n 13 permit udp 192.0.2.0 0.0.0.255 192.0.2.0 0.0.0.255 eq 6784\r\n15 remark * Drop all other attempts to the infrastructure address space *\r\n 20 deny udp any 192.0.2.0 0.0.0.255 eq bfd\r\n 30 permit ipv4 any any\r\n!\r\nRP/0/RSP0/CPU0:ASR9006#\r\n\r\nApply this iACL to all exposed interfaces.\r\n\r\nThe following example shows an iACL that allows only BFD packets with a Time to Live (TTL) of 255 (expected for single hop sessions):\r\n\r\n\r\nRP/0/RSP0/CPU0:ASR9006# show running-config ipv4 access-list\r\nipv4 access-list BFD_DROP_TTL\r\n5 remark * Drop based purely on TTL. Allow our Single Hop BFD sessions *\r\n10 permit udp any 192.0.2.0 0.0.0.255 eq bfd ttl eq 255\r\n11 remark * Depending on BFD deployment may need *\r\n12 permit udp any 192.0.2.0 0.0.0.255 eq 4784 ttl eq 255\r\n13 permit udp any 192.0.2.0 0.0.0.255 eq 6784 ttl eq 255\r\n14 remark * You would need to tune the above two lines for multi-hop sessions *\r\n15 remark * Deny anything else for BFD *\r\n20 deny udp any any eq bfd ttl lt 255\r\n21 remark * You would need to tune the above line for multi-hop sessions *\r\n30 permit ipv4 any any\r\n!\r\nRP/0/RSP0/CPU0:ASR9006#\r\n\r\nApply this iACL to all exposed interfaces.\r\n\r\nWhile this workaround and mitigation have been deployed and were proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.",
"title": "Workarounds"
},
{
"category": "general",
"text": "Cisco has released free software updates [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#ssu\"] that address the vulnerability described in this advisory. Customers with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.\r\n\r\nCustomers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:\r\nhttps://www.cisco.com/c/en/us/products/end-user-license-agreement.html [\"https://www.cisco.com/c/en/us/products/end-user-license-agreement.html\"]\r\n\r\nAdditionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.\r\n\r\nThe Cisco Support and Downloads page [\"https://www.cisco.com/c/en/us/support/index.html\"] on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.\r\n\r\nWhen considering software upgrades [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"], customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page [\"https://www.cisco.com/go/psirt\"], to determine exposure and a complete upgrade solution.\r\n\r\nIn all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.\r\n Customers Without Service Contracts\r\nCustomers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html [\"https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html\"]\r\n\r\nCustomers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.\r\n Fixed Releases\r\nIn the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"] as indicated in this section.\r\n Cisco IOS XR Software Release First Fixed Release 6.5 Migrate to a fixed release. 6.6 Migrate to a fixed release. 7.0 Migrate to a fixed release. 7.1 Migrate to a fixed release. 7.3 Migrate to a fixed release. 7.4 Migrate to a fixed release. 7.5 7.5.3 7.6 7.6.2 7.7 and later 7.7.1\r\nCisco has released the following SMUs to address this vulnerability.\r\n\r\nNote: Customers who require SMUs for releases that are not listed in the following table are advised to contact their support organization.\r\n Cisco IOS XR Software Release Platform SMU Name 7.1.3 ASR9K-X64 asr9k-x64-7.1.3.CSCwc39336 7.3.2 ASR9K-X64 asr9k-x64-7.3.2.CSCwc39336 7.5.2 ASR9K-X64 asr9k-x64-7.5.2.CSCwc39336\r\nThe Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.",
"title": "Fixed Software"
},
{
"category": "general",
"text": "To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy [\"http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html\"]. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.",
"title": "Vulnerability Policy"
},
{
"category": "general",
"text": "The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.",
"title": "Exploitation and Public Announcements"
},
{
"category": "general",
"text": "This vulnerability was found during the resolution of a Cisco TAC support case.",
"title": "Source"
},
{
"category": "legal_disclaimer",
"text": "THIS DOCUMENT IS PROVIDED ON AN \"AS IS\" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.\r\n\r\nA standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products.",
"title": "Legal Disclaimer"
}
],
"publisher": {
"category": "vendor",
"contact_details": "psirt@cisco.com",
"issuing_authority": "Cisco PSIRT",
"name": "Cisco",
"namespace": "https://wwww.cisco.com"
},
"references": [
{
"category": "self",
"summary": "Cisco IOS XR Software for ASR 9000 Series Routers Bidirectional Forwarding Detection Denial of Service Vulnerability",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"
},
{
"category": "external",
"summary": "Cisco Event Response: March 2023 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication",
"url": "https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74917"
},
{
"category": "external",
"summary": "Cisco Security Vulnerability Policy",
"url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
},
{
"category": "external",
"summary": "ASR 9000 Series Line Card Types",
"url": "https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html"
},
{
"category": "external",
"summary": "Vulnerable Products",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk#vp"
},
{
"category": "external",
"summary": "free software updates",
"url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#ssu"
},
{
"category": "external",
"summary": "https://www.cisco.com/c/en/us/products/end-user-license-agreement.html",
"url": "https://www.cisco.com/c/en/us/products/end-user-license-agreement.html"
},
{
"category": "external",
"summary": "Cisco\u0026nbsp;Support and Downloads page",
"url": "https://www.cisco.com/c/en/us/support/index.html"
},
{
"category": "external",
"summary": "considering software upgrades",
"url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"
},
{
"category": "external",
"summary": "Cisco\u0026nbsp;Security Advisories page",
"url": "https://www.cisco.com/go/psirt"
},
{
"category": "external",
"summary": "https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html",
"url": "https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"
},
{
"category": "external",
"summary": "Security Vulnerability Policy",
"url": "http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"
}
],
"title": "Cisco IOS XR Software for ASR 9000 Series Routers Bidirectional Forwarding Detection Denial of Service Vulnerability",
"tracking": {
"current_release_date": "2023-03-08T16:00:00+00:00",
"generator": {
"date": "2024-05-10T23:22:28+00:00",
"engine": {
"name": "TVCE"
}
},
"id": "cisco-sa-bfd-XmRescbT",
"initial_release_date": "2023-03-08T16:00:00+00:00",
"revision_history": [
{
"date": "2023-03-08T15:32:01+00:00",
"number": "1.0.0",
"summary": "Initial public release."
}
],
"status": "final",
"version": "1.0.0"
}
},
"product_tree": {
"branches": [
{
"branches": [
{
"category": "product_family",
"name": "Cisco IOS XR Software",
"product": {
"name": "Cisco IOS XR Software ",
"product_id": "CSAFPID-5834"
}
}
],
"category": "vendor",
"name": "Cisco"
}
]
},
"vulnerabilities": [
{
"cve": "CVE-2023-20049",
"ids": [
{
"system_name": "Cisco Bug ID",
"text": "CSCwc39336"
}
],
"notes": [
{
"category": "other",
"text": "Complete.",
"title": "Affected Product Comprehensiveness"
}
],
"product_status": {
"known_affected": [
"CSAFPID-5834"
]
},
"release_date": "2023-03-08T16:00:00+00:00",
"remediations": [
{
"category": "vendor_fix",
"details": "Cisco has released software updates that address this vulnerability.",
"product_ids": [
"CSAFPID-5834"
],
"url": "https://software.cisco.com"
}
],
"scores": [
{
"cvss_v3": {
"baseScore": 8.6,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
"version": "3.1"
},
"products": [
"CSAFPID-5834"
]
}
],
"title": "Cisco IOS XR Software for ASR 9000 Series Routers BFD Denial of Service Vulnerability"
}
]
}
WID-SEC-W-2023-0601
Vulnerability from csaf_certbund
Published
2023-03-08 23:00
Modified
2023-03-08 23:00
Summary
Cisco IOS XR: Mehrere Schwachstellen
Notes
Das BSI ist als Anbieter für die eigenen, zur Nutzung bereitgestellten Inhalte nach den allgemeinen Gesetzen verantwortlich. Nutzerinnen und Nutzer sind jedoch dafür verantwortlich, die Verwendung und/oder die Umsetzung der mit den Inhalten bereitgestellten Informationen sorgfältig im Einzelfall zu prüfen.
Produktbeschreibung
Cisco Internetwork Operating System (IOS) ist ein Betriebssystem, das für Cisco Geräte wie z. B. Router und Switches eingesetzt wird.
Angriff
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Cisco IOS XR ausnutzen, um einen Denial of Service Angriff durchzuführen oder Informationen offenzulegen.
Betroffene Betriebssysteme
- CISCO Appliance
{
"document": {
"aggregate_severity": {
"text": "hoch"
},
"category": "csaf_base",
"csaf_version": "2.0",
"distribution": {
"tlp": {
"label": "WHITE",
"url": "https://www.first.org/tlp/"
}
},
"lang": "de-DE",
"notes": [
{
"category": "legal_disclaimer",
"text": "Das BSI ist als Anbieter f\u00fcr die eigenen, zur Nutzung bereitgestellten Inhalte nach den allgemeinen Gesetzen verantwortlich. Nutzerinnen und Nutzer sind jedoch daf\u00fcr verantwortlich, die Verwendung und/oder die Umsetzung der mit den Inhalten bereitgestellten Informationen sorgf\u00e4ltig im Einzelfall zu pr\u00fcfen."
},
{
"category": "description",
"text": "Cisco Internetwork Operating System (IOS) ist ein Betriebssystem, das f\u00fcr Cisco Ger\u00e4te wie z. B. Router und Switches eingesetzt wird.",
"title": "Produktbeschreibung"
},
{
"category": "summary",
"text": "Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Cisco IOS XR ausnutzen, um einen Denial of Service Angriff durchzuf\u00fchren oder Informationen offenzulegen.",
"title": "Angriff"
},
{
"category": "general",
"text": "- CISCO Appliance",
"title": "Betroffene Betriebssysteme"
}
],
"publisher": {
"category": "other",
"contact_details": "csaf-provider@cert-bund.de",
"name": "Bundesamt f\u00fcr Sicherheit in der Informationstechnik",
"namespace": "https://www.bsi.bund.de"
},
"references": [
{
"category": "self",
"summary": "WID-SEC-W-2023-0601 - CSAF Version",
"url": "https://wid.cert-bund.de/.well-known/csaf/white/2023/wid-sec-w-2023-0601.json"
},
{
"category": "self",
"summary": "WID-SEC-2023-0601 - Portal Version",
"url": "https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2023-0601"
},
{
"category": "external",
"summary": "Cisco Security Advisory CISCO-SA-BFD-XMRESCBT vom 2023-03-08",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-load-infodisc-9rdOr5Fq"
},
{
"category": "external",
"summary": "Cisco Security Advisory CISCO-SA-BFD-XMRESCBT vom 2023-03-08",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"
}
],
"source_lang": "en-US",
"title": "Cisco IOS XR: Mehrere Schwachstellen",
"tracking": {
"current_release_date": "2023-03-08T23:00:00.000+00:00",
"generator": {
"date": "2024-02-15T17:18:31.201+00:00",
"engine": {
"name": "BSI-WID",
"version": "1.3.0"
}
},
"id": "WID-SEC-W-2023-0601",
"initial_release_date": "2023-03-08T23:00:00.000+00:00",
"revision_history": [
{
"date": "2023-03-08T23:00:00.000+00:00",
"number": "1",
"summary": "Initiale Fassung"
}
],
"status": "final",
"version": "1"
}
},
"product_tree": {
"branches": [
{
"branches": [
{
"category": "product_name",
"name": "Cisco IOS XR",
"product": {
"name": "Cisco IOS XR",
"product_id": "2062",
"product_identification_helper": {
"cpe": "cpe:/o:cisco:ios_xr:-"
}
}
}
],
"category": "vendor",
"name": "Cisco"
}
]
},
"vulnerabilities": [
{
"cve": "CVE-2023-20064",
"notes": [
{
"category": "description",
"text": "Es existiert eine Schwachstelle in Cisco IOS XR. Diese besteht in der Komponente \"Grub\" und ist darauf zur\u00fcckzuf\u00fchren, dass mehr Kommandos als ben\u00f6tigt ausgef\u00fchrt werden k\u00f6nnen. Ein anonymer Angreifer mit physischem Zugriff auf das Ger\u00e4t kann diese Schwachstellen ausnutzen, um Informationen offenzulegen."
}
],
"product_status": {
"known_affected": [
"2062"
]
},
"release_date": "2023-03-08T23:00:00Z",
"title": "CVE-2023-20064"
},
{
"cve": "CVE-2023-20049",
"notes": [
{
"category": "description",
"text": "Es existiert eine Schwachstelle in Cisco IOS XR. Diese ist auf den fehlerhaften Umgang mit BFD-Paketen zur\u00fcckzuf\u00fchren. Ein entfernter, anonymer Angreifer kann diese Schwachstelle ausnutzen, um einen Denial of Service Zustand herbeizuf\u00fchren."
}
],
"product_status": {
"known_affected": [
"2062"
]
},
"release_date": "2023-03-08T23:00:00Z",
"title": "CVE-2023-20049"
}
]
}
wid-sec-w-2023-0601
Vulnerability from csaf_certbund
Published
2023-03-08 23:00
Modified
2023-03-08 23:00
Summary
Cisco IOS XR: Mehrere Schwachstellen
Notes
Das BSI ist als Anbieter für die eigenen, zur Nutzung bereitgestellten Inhalte nach den allgemeinen Gesetzen verantwortlich. Nutzerinnen und Nutzer sind jedoch dafür verantwortlich, die Verwendung und/oder die Umsetzung der mit den Inhalten bereitgestellten Informationen sorgfältig im Einzelfall zu prüfen.
Produktbeschreibung
Cisco Internetwork Operating System (IOS) ist ein Betriebssystem, das für Cisco Geräte wie z. B. Router und Switches eingesetzt wird.
Angriff
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Cisco IOS XR ausnutzen, um einen Denial of Service Angriff durchzuführen oder Informationen offenzulegen.
Betroffene Betriebssysteme
- CISCO Appliance
{
"document": {
"aggregate_severity": {
"text": "hoch"
},
"category": "csaf_base",
"csaf_version": "2.0",
"distribution": {
"tlp": {
"label": "WHITE",
"url": "https://www.first.org/tlp/"
}
},
"lang": "de-DE",
"notes": [
{
"category": "legal_disclaimer",
"text": "Das BSI ist als Anbieter f\u00fcr die eigenen, zur Nutzung bereitgestellten Inhalte nach den allgemeinen Gesetzen verantwortlich. Nutzerinnen und Nutzer sind jedoch daf\u00fcr verantwortlich, die Verwendung und/oder die Umsetzung der mit den Inhalten bereitgestellten Informationen sorgf\u00e4ltig im Einzelfall zu pr\u00fcfen."
},
{
"category": "description",
"text": "Cisco Internetwork Operating System (IOS) ist ein Betriebssystem, das f\u00fcr Cisco Ger\u00e4te wie z. B. Router und Switches eingesetzt wird.",
"title": "Produktbeschreibung"
},
{
"category": "summary",
"text": "Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Cisco IOS XR ausnutzen, um einen Denial of Service Angriff durchzuf\u00fchren oder Informationen offenzulegen.",
"title": "Angriff"
},
{
"category": "general",
"text": "- CISCO Appliance",
"title": "Betroffene Betriebssysteme"
}
],
"publisher": {
"category": "other",
"contact_details": "csaf-provider@cert-bund.de",
"name": "Bundesamt f\u00fcr Sicherheit in der Informationstechnik",
"namespace": "https://www.bsi.bund.de"
},
"references": [
{
"category": "self",
"summary": "WID-SEC-W-2023-0601 - CSAF Version",
"url": "https://wid.cert-bund.de/.well-known/csaf/white/2023/wid-sec-w-2023-0601.json"
},
{
"category": "self",
"summary": "WID-SEC-2023-0601 - Portal Version",
"url": "https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2023-0601"
},
{
"category": "external",
"summary": "Cisco Security Advisory CISCO-SA-BFD-XMRESCBT vom 2023-03-08",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-load-infodisc-9rdOr5Fq"
},
{
"category": "external",
"summary": "Cisco Security Advisory CISCO-SA-BFD-XMRESCBT vom 2023-03-08",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"
}
],
"source_lang": "en-US",
"title": "Cisco IOS XR: Mehrere Schwachstellen",
"tracking": {
"current_release_date": "2023-03-08T23:00:00.000+00:00",
"generator": {
"date": "2024-02-15T17:18:31.201+00:00",
"engine": {
"name": "BSI-WID",
"version": "1.3.0"
}
},
"id": "WID-SEC-W-2023-0601",
"initial_release_date": "2023-03-08T23:00:00.000+00:00",
"revision_history": [
{
"date": "2023-03-08T23:00:00.000+00:00",
"number": "1",
"summary": "Initiale Fassung"
}
],
"status": "final",
"version": "1"
}
},
"product_tree": {
"branches": [
{
"branches": [
{
"category": "product_name",
"name": "Cisco IOS XR",
"product": {
"name": "Cisco IOS XR",
"product_id": "2062",
"product_identification_helper": {
"cpe": "cpe:/o:cisco:ios_xr:-"
}
}
}
],
"category": "vendor",
"name": "Cisco"
}
]
},
"vulnerabilities": [
{
"cve": "CVE-2023-20064",
"notes": [
{
"category": "description",
"text": "Es existiert eine Schwachstelle in Cisco IOS XR. Diese besteht in der Komponente \"Grub\" und ist darauf zur\u00fcckzuf\u00fchren, dass mehr Kommandos als ben\u00f6tigt ausgef\u00fchrt werden k\u00f6nnen. Ein anonymer Angreifer mit physischem Zugriff auf das Ger\u00e4t kann diese Schwachstellen ausnutzen, um Informationen offenzulegen."
}
],
"product_status": {
"known_affected": [
"2062"
]
},
"release_date": "2023-03-08T23:00:00Z",
"title": "CVE-2023-20064"
},
{
"cve": "CVE-2023-20049",
"notes": [
{
"category": "description",
"text": "Es existiert eine Schwachstelle in Cisco IOS XR. Diese ist auf den fehlerhaften Umgang mit BFD-Paketen zur\u00fcckzuf\u00fchren. Ein entfernter, anonymer Angreifer kann diese Schwachstelle ausnutzen, um einen Denial of Service Zustand herbeizuf\u00fchren."
}
],
"product_status": {
"known_affected": [
"2062"
]
},
"release_date": "2023-03-08T23:00:00Z",
"title": "CVE-2023-20049"
}
]
}
ghsa-3q76-jpjg-96ff
Vulnerability from github
Published
2023-03-10 00:30
Modified
2023-03-16 15:30
Severity ?
Details
A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads.
{
"affected": [],
"aliases": [
"CVE-2023-20049"
],
"database_specific": {
"cwe_ids": [
"CWE-119"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-03-09T22:15:00Z",
"severity": "HIGH"
},
"details": "A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads.",
"id": "GHSA-3q76-jpjg-96ff",
"modified": "2023-03-16T15:30:18Z",
"published": "2023-03-10T00:30:15Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-20049"
},
{
"type": "WEB",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
gsd-2023-20049
Vulnerability from gsd
Modified
2023-12-13 01:20
Details
A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads.
Aliases
Aliases
{
"GSD": {
"alias": "CVE-2023-20049",
"id": "GSD-2023-20049"
},
"gsd": {
"metadata": {
"exploitCode": "unknown",
"remediation": "unknown",
"reportConfidence": "confirmed",
"type": "vulnerability"
},
"osvSchema": {
"aliases": [
"CVE-2023-20049"
],
"details": "A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads.",
"id": "GSD-2023-20049",
"modified": "2023-12-13T01:20:28.902895Z",
"schema_version": "1.4.0"
}
},
"namespaces": {
"cve.org": {
"CVE_data_meta": {
"ASSIGNER": "psirt@cisco.com",
"DATE_PUBLIC": "2023-03-08T16:00:00",
"ID": "CVE-2023-20049",
"STATE": "PUBLIC",
"TITLE": "Cisco IOS XR Software for ASR 9000 Series Routers Bidirectional Forwarding Detection Denial of Service Vulnerability"
},
"affects": {
"vendor": {
"vendor_data": [
{
"product": {
"product_data": [
{
"product_name": "Cisco IOS XR Software ",
"version": {
"version_data": [
{
"version_value": "n/a"
}
]
}
}
]
},
"vendor_name": "Cisco"
}
]
}
},
"data_format": "MITRE",
"data_type": "CVE",
"data_version": "4.0",
"description": {
"description_data": [
{
"lang": "eng",
"value": "A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads."
}
]
},
"exploit": [
{
"lang": "eng",
"value": "The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory. "
}
],
"impact": {
"cvss": {
"baseScore": "8.6",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H ",
"version": "3.0"
}
},
"problemtype": {
"problemtype_data": [
{
"description": [
{
"lang": "eng",
"value": "CWE-805"
}
]
}
]
},
"references": {
"reference_data": [
{
"name": "20230308 Cisco IOS XR Software for ASR 9000 Series Routers Bidirectional Forwarding Detection Denial of Service Vulnerability",
"refsource": "CISCO",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"
}
]
},
"source": {
"advisory": "cisco-sa-bfd-XmRescbT",
"defect": [
[
"CSCwc39336"
]
],
"discovery": "INTERNAL"
}
},
"nvd.nist.gov": {
"configurations": {
"CVE_data_version": "4.0",
"nodes": [
{
"children": [
{
"children": [],
"cpe_match": [
{
"cpe23Uri": "cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*",
"cpe_name": [],
"versionEndExcluding": "7.5.3",
"vulnerable": true
},
{
"cpe23Uri": "cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*",
"cpe_name": [],
"versionEndExcluding": "7.6.2",
"versionStartIncluding": "7.6",
"vulnerable": true
},
{
"cpe23Uri": "cpe:2.3:o:cisco:ios_xr:7.7:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": true
}
],
"operator": "OR"
},
{
"children": [],
"cpe_match": [
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9000v-v2:-:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": false
},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9001:-:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": false
},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9006:-:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": false
},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9010:-:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": false
},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9901:-:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": false
},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9902:-:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": false
},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9903:-:*:*:*:*:*:*:*",
"cpe_name": [],
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},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9904:-:*:*:*:*:*:*:*",
"cpe_name": [],
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},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9906:-:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": false
},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9910:-:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": false
},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9912:-:*:*:*:*:*:*:*",
"cpe_name": [],
"vulnerable": false
},
{
"cpe23Uri": "cpe:2.3:h:cisco:asr_9922:-:*:*:*:*:*:*:*",
"cpe_name": [],
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}
],
"operator": "OR"
}
],
"cpe_match": [],
"operator": "AND"
}
]
},
"cve": {
"CVE_data_meta": {
"ASSIGNER": "psirt@cisco.com",
"ID": "CVE-2023-20049"
},
"data_format": "MITRE",
"data_type": "CVE",
"data_version": "4.0",
"description": {
"description_data": [
{
"lang": "en",
"value": "A vulnerability in the bidirectional forwarding detection (BFD) hardware offload feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of malformed BFD packets that are received on line cards where the BFD hardware offload feature is enabled. An attacker could exploit this vulnerability by sending a crafted IPv4 BFD packet to an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset, resulting in loss of traffic over that line card while the line card reloads."
}
]
},
"problemtype": {
"problemtype_data": [
{
"description": [
{
"lang": "en",
"value": "CWE-119"
}
]
}
]
},
"references": {
"reference_data": [
{
"name": "20230308 Cisco IOS XR Software for ASR 9000 Series Routers Bidirectional Forwarding Detection Denial of Service Vulnerability",
"refsource": "CISCO",
"tags": [
"Vendor Advisory"
],
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bfd-XmRescbT"
}
]
}
},
"impact": {
"baseMetricV3": {
"cvssV3": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6
}
},
"lastModifiedDate": "2023-03-16T15:23Z",
"publishedDate": "2023-03-09T22:15Z"
}
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.