GHSA-P9QP-C452-F9R7

Vulnerability from github – Published: 2023-05-24 17:21 – Updated: 2024-09-30 20:25
VLAI?
Summary
Synapse Denial of service due to incorrect application of event authorization rules during state resolution
Details

Impact

If Synapse and a malicious homeserver are both joined to the same room, the malicious homeserver can trick Synapse into accepting previously rejected events into its view of the current state of that room. This can be exploited in a way that causes all further messages and state changes sent in that room from the vulnerable homeserver to be rejected.

Synapse homeservers are affected by this issue if and only if they are joined to rooms which members of untrusted homeservers are joined or invited to.

  • Synapse homeservers in rooms available over public federation are affected.
  • Synapse homeservers with federation disabled are not affected.
  • Synapse homeservers in a closed federation containing only trusted servers are not affected.
  • Synapse homeservers which are only joined to rooms with federation disabled[^1] are not affected.

Patches

Administrators of homeservers with federation enabled are advised to upgrade to 1.68.0 or higher.

Workarounds

  • Federation can be disabled by setting federation_domain_whitelist to an empty list ([]). from the vulnerable homeserver to be rejected. This issue has been patched in version 1.68.0

References

  • https://github.com/matrix-org/synapse/pull/13723

[^1]: See m.federate in the m.room.create definition.

For more information

If you have any questions or comments about this advisory, e-mail us at security@matrix.org.

Severity ?
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.1 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "matrix-synapse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.62.0"
            },
            {
              "fixed": "1.68.0rc1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-39374"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-05-24T17:21:33Z",
    "nvd_published_at": "2023-05-26T14:15:10Z",
    "severity": "HIGH"
  },
  "details": "### Impact\nIf Synapse and a malicious homeserver are both joined to the same room, the malicious homeserver can trick Synapse into accepting previously rejected events into its view of the current state of that room. This can be exploited in a way that causes all further messages and state changes sent in that room from the vulnerable homeserver to be rejected.\n\nSynapse homeservers are affected by this issue if and only if they are joined to rooms which members of untrusted homeservers are joined or invited to. \n\n- Synapse homeservers in rooms available over public federation **are** affected.\n- Synapse homeservers with federation disabled are not affected.\n- Synapse homeservers in a closed federation containing only trusted servers are not affected.\n- Synapse homeservers which are only joined to rooms with federation disabled[^1] are not affected.\n\n### Patches\nAdministrators of homeservers with federation enabled are advised to upgrade to 1.68.0 or higher.\n\n### Workarounds\n * Federation can be disabled by setting [`federation_domain_whitelist`](https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#federation_domain_whitelist) to an empty list (`[]`). from the vulnerable homeserver to be rejected. This issue has been patched in version 1.68.0\n\n### References\n- https://github.com/matrix-org/synapse/pull/13723\n\n[^1]: See `m.federate` in the [`m.room.create` definition](https://spec.matrix.org/v1.4/client-server-api/#mroomcreate).\n\n### For more information\n\nIf you have any questions or comments about this advisory, e-mail us at [security@matrix.org](mailto:security@matrix.org).",
  "id": "GHSA-p9qp-c452-f9r7",
  "modified": "2024-09-30T20:25:22Z",
  "published": "2023-05-24T17:21:33Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-p9qp-c452-f9r7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-39374"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/pull/13723"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/b73cbb82157d9666e8d667733afebc0d09ed858c"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/matrix-org/synapse"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2023-66.yaml"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Synapse Denial of service due to incorrect application of event authorization rules during state resolution"
}


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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.