cisco-sa-snort-bypass-ptry37fx
Vulnerability from csaf_cisco
Published
2024-10-23 16:00
Modified
2024-10-23 16:00
Summary
Cisco Firepower Threat Defense Software TCP Snort 3 Detection Engine Bypass Vulnerability

Notes

Summary
A vulnerability in the interaction between the TCP Intercept feature and the Snort 3 detection engine on Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured policies on an affected system. Devices that are configured with Snort 2 are not affected by this vulnerability. This vulnerability is due to a logic error when handling embryonic (half-open) TCP connections. An attacker could exploit this vulnerability by sending a crafted traffic pattern through an affected device. A successful exploit could allow unintended traffic to enter the network protected by the affected device. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability. This advisory is part of the October 2024 release of the Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: October 2024 Semiannual Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75300"].
Vulnerable Products
At the time of publication, this vulnerability affected Cisco FTD Software and Cisco FirePOWER Services if they were configured with a maximum embryonic connection using the Snort 3 detection engine. For information about which Cisco software releases are vulnerable, see the Fixed Software ["#fs"] section of this advisory. Determine the Snort Configuration on Cisco FTD Software To determine if Snort 3 is running on Cisco FTD Software, see Determine the Active Snort Version that Runs on Firepower Threat Defense (FTD) ["https://www.cisco.com/c/en/us/support/docs/security/secure-firewall-threat-defense/220415-determine-the-active-snort-version-that.html"]. Snort 3 has to be active for this vulnerability to be exploited. Determine the Embryonic Configuration on Cisco FTD Software The default value for embryonic connections is 0, which is unlimited connections. Deployments with the default configuration are considered not vulnerable. To determine the embryonic connection configuration, use the show running-config policy-map | include embryonic FTD CLI command. The following example shows the output of the command on a device that has a maximum embryonic connection set: FTD# show running-config policy-map | include embryonic set connection conn-max 1000 embryonic-conn-max 3000 FTD# If the command shows no output, the device is considered not vulnerable. For more information on embryonic connections, see the Protect Servers from a SYN Flood DoS Attack (TCP Intercept) ["https://www.cisco.com/c/en/us/td/docs/security/firepower/630/configuration/guide/fpmc-config-guide-v63/threat_defense_service_policies.html#id_71090"] section or the What Are Connection Settings? ["https://www.cisco.com/c/en/us/td/docs/security/secure-firewall/management-center/device-config/720/management-center-device-config-72/access-service-policies.html#ID-2068-00000008"] section of of the Cisco Secure Firewall Management Center Device Configuration Guide.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products ["#vp"] section of this advisory are known to be affected by this vulnerability. Cisco has confirmed that this vulnerability does not affect the following products: Cisco Adaptive Security Appliance (ASA) Software Cisco Secure Firewall Management Center (FMC) Software, formerly Firepower Management Center Software Open Source Snort 2 Open Source Snort 3
Workarounds
There is a workaround that addresses this vulnerability. To implement the workaround, turn off pkt-decode-optimization using the no asp inspect-dp pkt-decode-optimization FTD CLI command, as shown in the following example: FTD# no asp inspect-dp pkt-decode-optimization FTD# While this workaround has been deployed and was 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
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. Cisco ASA, FMC, and FTD Software To help customers determine their exposure to vulnerabilities in Cisco ASA, FMC, and FTD Software, Cisco provides the Cisco Software Checker ["https://sec.cloudapps.cisco.com/security/center/softwarechecker.x"]. This tool identifies any Cisco security advisories that impact a specific software release and the earliest release that fixes the vulnerabilities that are described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities that are described in all the advisories that the Software Checker identifies (“Combined First Fixed”). To use the tool, go to the Cisco Software Checker ["https://sec.cloudapps.cisco.com/security/center/softwarechecker.x"] page and follow the instructions. Alternatively, use the following form to search for vulnerabilities that affect a specific software release. To use the form, follow these steps: Choose which advisories the tool will search—all advisories, only advisories with a Critical or High Security Impact Rating (SIR) ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#asr"], or only this advisory. Choose the appropriate software. Choose the appropriate platform. Enter a release number—for example, 9.16.2.11 for Cisco ASA Software or 6.6.7 for Cisco FTD Software. Click Check. Only this advisory All Critical and High advisories All advisories Cisco ASA Software Cisco FMC Software Cisco FTD Software Any Platform 3000 Series Industrial Security Appliances (ISA) ASA 5500-X Series Firewalls ASA Service Module Adaptive Security Virtual Appliance (ASAv) Firepower 1000 Series Firepower 2100 Series Firepower 4100 Series Firepower 9000 Series Firepower NGFW Virtual Secure Firewall 3100 Series Firepower Management Center Appliances For instructions on upgrading a Cisco FTD device, see the appropriate Cisco FMC upgrade guide ["https://www.cisco.com/c/en/us/support/security/defense-center/products-installation-guides-list.html"]. Additional Resources For help determining the best Cisco ASA, FMC, or FTD Software release, see the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance. Cisco ASA Compatibility ["https://www.cisco.com/c/en/us/td/docs/security/asa/compatibility/asamatrx.html"] Cisco Secure Firewall ASA Upgrade Guide ["https://www.cisco.com/c/en/us/td/docs/security/asa/upgrade/asa-upgrade/planning.html"] Cisco Secure Firewall Threat Defense Compatibility Guide ["https://www.cisco.com/c/en/us/td/docs/security/secure-firewall/compatibility/threat-defense-compatibility.html"]
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 Product Security Incident Response Team (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.


To clipboard 

{
  "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 interaction between the TCP Intercept feature and the Snort 3 detection engine on Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured policies on an affected system. Devices that are configured with Snort 2 are not affected by this vulnerability.\r\n\r\nThis vulnerability is due to a logic error when handling embryonic (half-open) TCP connections. An attacker could exploit this vulnerability by sending a crafted traffic pattern through an affected device. A successful exploit could allow unintended traffic to enter the network protected by the affected device.\r\n\r\nCisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.\r\n\r\n\r\n\r\nThis advisory is part of the October 2024 release of the Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: October 2024 Semiannual Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication [\"https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75300\"].",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "At the time of publication, this vulnerability affected Cisco FTD Software and Cisco FirePOWER Services if they were configured with a maximum embryonic connection using the Snort 3 detection engine.\r\n\r\nFor information about which Cisco software releases are vulnerable, see the Fixed Software [\"#fs\"] section of this advisory.\r\n    Determine the Snort Configuration on Cisco FTD Software\r\nTo determine if Snort 3 is running on Cisco FTD Software, see Determine the Active Snort Version that Runs on Firepower Threat Defense (FTD) [\"https://www.cisco.com/c/en/us/support/docs/security/secure-firewall-threat-defense/220415-determine-the-active-snort-version-that.html\"]. Snort 3 has to be active for this vulnerability to be exploited.\r\n    Determine the Embryonic Configuration on Cisco FTD Software\r\nThe default value for embryonic connections is 0, which is unlimited connections. Deployments with the default configuration are considered not vulnerable.\r\n\r\nTo determine the embryonic connection configuration, use the show running-config policy-map | include embryonic FTD CLI command. The following example shows the output of the command on a device that has a maximum embryonic connection set:\r\n\r\n\r\nFTD# show running-config policy-map | include embryonic\r\n  set connection conn-max 1000 embryonic-conn-max 3000\r\nFTD#\r\n\r\nIf the command shows no output, the device is considered not vulnerable.\r\n\r\nFor more information on embryonic connections, see the Protect Servers from a SYN Flood DoS Attack (TCP Intercept) [\"https://www.cisco.com/c/en/us/td/docs/security/firepower/630/configuration/guide/fpmc-config-guide-v63/threat_defense_service_policies.html#id_71090\"] section or the What Are Connection Settings? [\"https://www.cisco.com/c/en/us/td/docs/security/secure-firewall/management-center/device-config/720/management-center-device-config-72/access-service-policies.html#ID-2068-00000008\"] section of of the Cisco Secure Firewall Management Center Device Configuration Guide.",
        "title": "Vulnerable Products"
      },
      {
        "category": "general",
        "text": "Only products listed in the Vulnerable Products [\"#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 products:\r\n\r\nCisco Adaptive Security Appliance (ASA) Software\r\nCisco Secure Firewall Management Center (FMC) Software, formerly Firepower Management Center Software\r\nOpen Source Snort 2\r\nOpen Source Snort 3",
        "title": "Products Confirmed Not Vulnerable"
      },
      {
        "category": "general",
        "text": "There is a workaround that addresses this vulnerability. To implement the workaround, turn off pkt-decode-optimization using the no asp inspect-dp pkt-decode-optimization FTD CLI command, as shown in the following example:\r\n\r\n\r\nFTD# no asp inspect-dp pkt-decode-optimization\r\nFTD#\r\n\r\nWhile this workaround has been deployed and was 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": "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.\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\nCisco ASA, FMC, and FTD Software\r\nTo help customers determine their exposure to vulnerabilities in Cisco ASA, FMC, and FTD Software, Cisco provides the Cisco Software Checker [\"https://sec.cloudapps.cisco.com/security/center/softwarechecker.x\"]. This tool identifies any Cisco security advisories that impact a specific software release and the earliest release that fixes the vulnerabilities that are described in each advisory (\u201cFirst Fixed\u201d). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities that are described in all the advisories that the Software Checker identifies (\u201cCombined First Fixed\u201d).\r\n\r\nTo use the tool, go to the Cisco Software Checker [\"https://sec.cloudapps.cisco.com/security/center/softwarechecker.x\"] page and follow the instructions. Alternatively, use the following form to search for vulnerabilities that affect a specific software release. To use the form, follow these steps:\r\n\r\nChoose which advisories the tool will search\u2014all advisories, only advisories with a Critical or High Security Impact Rating (SIR) [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#asr\"], or only this advisory.\r\nChoose the appropriate software.\r\nChoose the appropriate platform.\r\nEnter a release number\u2014for example, 9.16.2.11 for Cisco ASA Software or 6.6.7 for Cisco FTD Software.\r\nClick Check.\r\n    Only this advisory All Critical and High advisories All advisories  Cisco ASA Software Cisco FMC Software Cisco FTD Software  Any Platform 3000 Series Industrial Security Appliances (ISA) ASA 5500-X Series Firewalls ASA Service Module Adaptive Security Virtual Appliance (ASAv) Firepower 1000 Series Firepower 2100 Series Firepower 4100 Series Firepower 9000 Series Firepower NGFW Virtual Secure Firewall 3100 Series Firepower Management Center Appliances\r\n\r\n\r\n\r\n\r\n\r\nFor instructions on upgrading a Cisco FTD device, see the appropriate Cisco FMC upgrade guide [\"https://www.cisco.com/c/en/us/support/security/defense-center/products-installation-guides-list.html\"].\r\n\r\n Additional Resources\r\nFor help determining the best Cisco ASA, FMC, or FTD Software release, see the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance.\r\n\r\nCisco ASA Compatibility [\"https://www.cisco.com/c/en/us/td/docs/security/asa/compatibility/asamatrx.html\"]\r\nCisco Secure Firewall ASA Upgrade Guide [\"https://www.cisco.com/c/en/us/td/docs/security/asa/upgrade/asa-upgrade/planning.html\"]\r\nCisco Secure Firewall Threat Defense Compatibility Guide [\"https://www.cisco.com/c/en/us/td/docs/security/secure-firewall/compatibility/threat-defense-compatibility.html\"]",
        "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 Product Security Incident Response Team (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 Firepower Threat Defense Software TCP Snort 3 Detection Engine Bypass Vulnerability",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-bypass-PTry37fX"
      },
      {
        "category": "external",
        "summary": "Cisco Event Response: October 2024 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication",
        "url": "https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75300"
      },
      {
        "category": "external",
        "summary": "Cisco Security Vulnerability Policy",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
      },
      {
        "category": "external",
        "summary": "Determine the Active Snort Version that Runs on Firepower Threat Defense (FTD)",
        "url": "https://www.cisco.com/c/en/us/support/docs/security/secure-firewall-threat-defense/220415-determine-the-active-snort-version-that.html"
      },
      {
        "category": "external",
        "summary": "Protect Servers from a SYN Flood DoS Attack (TCP Intercept)",
        "url": "https://www.cisco.com/c/en/us/td/docs/security/firepower/630/configuration/guide/fpmc-config-guide-v63/threat_defense_service_policies.html#id_71090"
      },
      {
        "category": "external",
        "summary": "What Are Connection Settings?",
        "url": "https://www.cisco.com/c/en/us/td/docs/security/secure-firewall/management-center/device-config/720/management-center-device-config-72/access-service-policies.html#ID-2068-00000008"
      },
      {
        "category": "external",
        "summary": "considering software upgrades",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"
      },
      {
        "category": "external",
        "summary": "Cisco Security Advisories page",
        "url": "https://www.cisco.com/go/psirt"
      },
      {
        "category": "external",
        "summary": "Cisco Software Checker",
        "url": "https://sec.cloudapps.cisco.com/security/center/softwarechecker.x"
      },
      {
        "category": "external",
        "summary": "Security Impact Rating (SIR)",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#asr"
      },
      {
        "category": "external",
        "summary": "Cisco FMC upgrade guide",
        "url": "https://www.cisco.com/c/en/us/support/security/defense-center/products-installation-guides-list.html"
      },
      {
        "category": "external",
        "summary": "Cisco ASA Compatibility",
        "url": "https://www.cisco.com/c/en/us/td/docs/security/asa/compatibility/asamatrx.html"
      },
      {
        "category": "external",
        "summary": "Cisco Secure Firewall ASA Upgrade Guide",
        "url": "https://www.cisco.com/c/en/us/td/docs/security/asa/upgrade/asa-upgrade/planning.html"
      },
      {
        "category": "external",
        "summary": "Cisco Secure Firewall Threat Defense Compatibility Guide",
        "url": "https://www.cisco.com/c/en/us/td/docs/security/secure-firewall/compatibility/threat-defense-compatibility.html"
      },
      {
        "category": "external",
        "summary": "Security Vulnerability Policy",
        "url": "http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"
      }
    ],
    "title": "Cisco Firepower Threat Defense Software TCP Snort 3 Detection Engine Bypass Vulnerability",
    "tracking": {
      "current_release_date": "2024-10-23T16:00:00+00:00",
      "generator": {
        "date": "2024-10-23T15:58:55+00:00",
        "engine": {
          "name": "TVCE"
        }
      },
      "id": "cisco-sa-snort-bypass-PTry37fX",
      "initial_release_date": "2024-10-23T16:00:00+00:00",
      "revision_history": [
        {
          "date": "2024-10-23T15:57:29+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 Firepower Threat Defense Software",
            "product": {
              "name": "Cisco Firepower Threat Defense Software ",
              "product_id": "CSAFPID-220203"
            }
          }
        ],
        "category": "vendor",
        "name": "Cisco"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2024-20407",
      "ids": [
        {
          "system_name": "Cisco Bug ID",
          "text": "CSCwi42291"
        }
      ],
      "notes": [
        {
          "category": "other",
          "text": "Complete.",
          "title": "Affected Product Comprehensiveness"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-220203"
        ]
      },
      "release_date": "2024-10-23T16:00:00+00:00",
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Cisco has released software updates that address this vulnerability.",
          "product_ids": [
            "CSAFPID-220203"
          ],
          "url": "https://software.cisco.com"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 5.8,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-220203"
          ]
        }
      ],
      "title": "Cisco Firepower Threat Defense Software TCP Snort 3 Detection Engine Bypass Vulnerability"
    }
  ]
}


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Sightings

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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.
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  • 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.