GHSA-35G4-QX3C-VJHX

Vulnerability from github – Published: 2021-06-21 17:09 – Updated: 2021-06-16 20:08
VLAI?
Summary
Automatic room upgrade handling can be used maliciously to bridge a room non-consentually
Details

Impact

If a bridge has room upgrade handling turned on in the configuration (the roomUpgradeOpts key when instantiating a new Bridge instance.), any m.room.tombstone event it encounters will be used to unbridge the current room and bridge into the target room. However, the target room m.room.create event is not checked to verify if the predecessor field contains the previous room. This means that any mailcious admin of a bridged room can repoint the traffic to a different room without the new room being aware.

Patches

Versions 2.6.1 and greater are patched.

Workarounds

Disabling the automatic room upgrade handling can be done by removing the roomUpgradeOpts key from the Bridge class options.

References

The issue is patched by https://github.com/matrix-org/matrix-appservice-bridge/pull/330

For more information]

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

Severity ?
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "matrix-appservice-bridge"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.6.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-32659"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-306"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-06-16T20:08:37Z",
    "nvd_published_at": "2021-06-16T19:15:00Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nIf a bridge has room upgrade handling turned on in the configuration (the `roomUpgradeOpts` key when instantiating a new `Bridge` instance.), any `m.room.tombstone` event it encounters will be used to unbridge the current room and bridge into the target room. However, the target room `m.room.create` event is not checked to verify if the `predecessor` field contains the previous room. This means that any mailcious admin of a bridged room can repoint the traffic to a different room without the new room being aware.\n\n\n### Patches\n\nVersions 2.6.1 and greater are patched.\n\n### Workarounds\n\nDisabling the automatic room upgrade handling can be done by removing the `roomUpgradeOpts` key from the `Bridge` class options. \n\n### References\n\nThe issue is patched by https://github.com/matrix-org/matrix-appservice-bridge/pull/330\n\n### For more information]\n\nIf you have any questions or comments about this advisory, email us at security@matrix.org.",
  "id": "GHSA-35g4-qx3c-vjhx",
  "modified": "2021-06-16T20:08:37Z",
  "published": "2021-06-21T17:09:22Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-35g4-qx3c-vjhx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-32659"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/pull/330"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/commit/b69e745584a34fcfd858df33e4631e420da07b9f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/releases/tag/2.6.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Automatic room upgrade handling can be used maliciously to bridge a room non-consentually "
}


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  • 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.
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  • 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.



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