Vulnerability-Lookup

GSD-2023-32323

Vulnerability from gsd - Updated: 2023-12-13 01:20

Details

Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y. Synapse instances with federation disabled are not affected. In versions of Synapse up to and including 1.73, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event. Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.

Aliases

CVE-2023-32323

Aliases

CVE-2023-32323

JSON

To clipboard

{
  "GSD": {
    "alias": "CVE-2023-32323",
    "id": "GSD-2023-32323"
  },
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2023-32323"
      ],
      "details": "Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y. Synapse instances with federation disabled are not affected. In versions of Synapse up to and including 1.73, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event. Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.\n\n",
      "id": "GSD-2023-32323",
      "modified": "2023-12-13T01:20:23.408951Z",
      "schema_version": "1.4.0"
    }
  },
  "namespaces": {
    "cve.org": {
      "CVE_data_meta": {
        "ASSIGNER": "security-advisories@github.com",
        "ID": "CVE-2023-32323",
        "STATE": "PUBLIC"
      },
      "affects": {
        "vendor": {
          "vendor_data": [
            {
              "product": {
                "product_data": [
                  {
                    "product_name": "synapse",
                    "version": {
                      "version_data": [
                        {
                          "version_affected": "=",
                          "version_value": "\u003c 1.74.0"
                        }
                      ]
                    }
                  }
                ]
              },
              "vendor_name": "matrix-org"
            }
          ]
        }
      },
      "data_format": "MITRE",
      "data_type": "CVE",
      "data_version": "4.0",
      "description": {
        "description_data": [
          {
            "lang": "eng",
            "value": "Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y. Synapse instances with federation disabled are not affected. In versions of Synapse up to and including 1.73, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event. Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.\n\n"
          }
        ]
      },
      "impact": {
        "cvss": [
          {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L",
            "version": "3.1"
          }
        ]
      },
      "problemtype": {
        "problemtype_data": [
          {
            "description": [
              {
                "cweId": "CWE-20",
                "lang": "eng",
                "value": "CWE-20: Improper Input Validation"
              }
            ]
          }
        ]
      },
      "references": {
        "reference_data": [
          {
            "name": "https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr",
            "refsource": "MISC",
            "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr"
          },
          {
            "name": "https://github.com/matrix-org/synapse/issues/14492",
            "refsource": "MISC",
            "url": "https://github.com/matrix-org/synapse/issues/14492"
          },
          {
            "name": "https://github.com/matrix-org/synapse/pull/14642",
            "refsource": "MISC",
            "url": "https://github.com/matrix-org/synapse/pull/14642"
          },
          {
            "name": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/",
            "refsource": "MISC",
            "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/"
          }
        ]
      },
      "source": {
        "advisory": "GHSA-f3wc-3vxv-xmvr",
        "discovery": "UNKNOWN"
      }
    },
    "gitlab.com": {
      "advisories": [
        {
          "affected_range": "\u003c1.74.0",
          "affected_versions": "All versions before 1.74.0",
          "cvss_v3": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
          "cwe_ids": [
            "CWE-1035",
            "CWE-20",
            "CWE-937"
          ],
          "date": "2023-06-02",
          "description": "### Impact\n\nA malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y.\n\nSynapse instances with federation disabled are not affected.\n\n#### Details\n\nThe Matrix protocol allows homeservers to provide an `invite_room_state` field on a [room invite](https://spec.matrix.org/v1.5/client-server-api/#mroommember) containing a [summary of room state](https://spec.matrix.org/v1.5/client-server-api/#stripped-state). In versions of Synapse up to and including v1.73.0, Synapse does not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event.\n\nAn attacker with an account on a vulnerable Synapse homeserver X could exploit this by having X create an over-sized invite event in a room with a user from another homeserver Y. Once acknowledged by the invitee\u0027s homeserver, the invite event would be sent in a batch of events to Y. If the malicious invite is so large that the entire batch is rejected as too large, X\u0027s outgoing traffic to Y would become \"stuck\", meaning that messages and state events created by X would remain unseen by Y.\n\n### Patches\n\nSynapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.\n\n### Workarounds\n\nThere are no robust workarounds.\n\nThis attack needs an account on Synapse homeserver X to deny federation from X to another homeserver Y. As a partial mitigation, Synapse operators can disable open registration to limit the ability of attackers to create new accounts on homeserver X.\n\nIf homeserver X has been attacked in this way, restarting it will resume outgoing federation by entering \"catchup mode\". For catchup mode to ignore the oversized invites, every attacked room must have a correctly-sized event sent by X which is newer than any oversized invite. This is difficult to arrange, and does not prevent the attacker from repeating their attack.\n\n### References\n\n- https://github.com/matrix-org/synapse/issues/14492 was caused by this issue.\n- https://github.com/matrix-org/synapse/issues/14642 includes the patch described above.\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).",
          "fixed_versions": [
            "1.74.0"
          ],
          "identifier": "CVE-2023-32323",
          "identifiers": [
            "CVE-2023-32323",
            "GHSA-f3wc-3vxv-xmvr"
          ],
          "not_impacted": "All versions starting from 1.74.0",
          "package_slug": "pypi/matrix-synapse",
          "pubdate": "2023-05-26",
          "solution": "Upgrade to version 1.74.0 or above.",
          "title": "Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites",
          "urls": [
            "https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr",
            "https://github.com/matrix-org/synapse/issues/14492",
            "https://github.com/matrix-org/synapse/pull/14642",
            "https://github.com/advisories/GHSA-f3wc-3vxv-xmvr"
          ],
          "uuid": "8396c4f6-65a5-4f05-b04a-d5fe94312bf8"
        }
      ]
    },
    "nvd.nist.gov": {
      "configurations": {
        "CVE_data_version": "4.0",
        "nodes": [
          {
            "children": [],
            "cpe_match": [
              {
                "cpe23Uri": "cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*",
                "cpe_name": [],
                "versionEndExcluding": "1.74.0",
                "vulnerable": true
              }
            ],
            "operator": "OR"
          }
        ]
      },
      "cve": {
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          "ASSIGNER": "security-advisories@github.com",
          "ID": "CVE-2023-32323"
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        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "en",
              "value": "Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y. Synapse instances with federation disabled are not affected. In versions of Synapse up to and including 1.73, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event. Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.\n\n"
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "en",
                  "value": "CWE-20"
                }
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        },
        "references": {
          "reference_data": [
            {
              "name": "https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr",
              "refsource": "MISC",
              "tags": [
                "Mitigation",
                "Vendor Advisory"
              ],
              "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr"
            },
            {
              "name": "https://github.com/matrix-org/synapse/pull/14642",
              "refsource": "MISC",
              "tags": [
                "Patch"
              ],
              "url": "https://github.com/matrix-org/synapse/pull/14642"
            },
            {
              "name": "https://github.com/matrix-org/synapse/issues/14492",
              "refsource": "MISC",
              "tags": [
                "Exploit",
                "Issue Tracking"
              ],
              "url": "https://github.com/matrix-org/synapse/issues/14492"
            },
            {
              "name": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/",
              "refsource": "MISC",
              "tags": [],
              "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/"
            }
          ]
        }
      },
      "impact": {
        "baseMetricV3": {
          "cvssV3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 4.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
            "version": "3.1"
          },
          "exploitabilityScore": 2.8,
          "impactScore": 1.4
        }
      },
      "lastModifiedDate": "2023-09-18T04:15Z",
      "publishedDate": "2023-05-26T14:15Z"
    }
  }
}

CVE-2023-32323 (GCVE-0-2023-32323)

Vulnerability from cvelistv5 – Published: 2023-05-26 13:32 – Updated: 2025-02-13 16:50

Title

Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites

Summary

Severity

5 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-01-14 20:00 UTC

CWE

CWE-20 - Improper Input Validation

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/matrix-org/synapse/security/ad…	x_refsource_CONFIRM
https://github.com/matrix-org/synapse/issues/14492	x_refsource_MISC
https://github.com/matrix-org/synapse/pull/14642	x_refsource_MISC
https://lists.fedoraproject.org/archives/list/pac…

Impacted products

1 product

Vendor	Product	Version
matrix-org	synapse	Affected: < 1.74.0

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-02T15:10:24.899Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
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        "references": [
          {
            "name": "https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr",
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr"
          },
          {
            "name": "https://github.com/matrix-org/synapse/issues/14492",
            "tags": [
              "x_refsource_MISC",
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            "url": "https://github.com/matrix-org/synapse/issues/14492"
          },
          {
            "name": "https://github.com/matrix-org/synapse/pull/14642",
            "tags": [
              "x_refsource_MISC",
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            "url": "https://github.com/matrix-org/synapse/pull/14642"
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          {
            "tags": [
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            "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2023-32323",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-01-14T20:00:17.125564Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
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          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-01-14T20:00:25.608Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
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        {
          "product": "synapse",
          "vendor": "matrix-org",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.74.0"
            }
          ]
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      "descriptions": [
        {
          "lang": "en",
          "value": "Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y. Synapse instances with federation disabled are not affected. In versions of Synapse up to and including 1.73, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event. Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L",
            "version": "3.1"
          }
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      ],
      "problemTypes": [
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          "descriptions": [
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              "description": "CWE-20: Improper Input Validation",
              "lang": "en",
              "type": "CWE"
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      "providerMetadata": {
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      },
      "references": [
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          "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr"
        },
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          "tags": [
            "x_refsource_MISC"
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          "url": "https://github.com/matrix-org/synapse/issues/14492"
        },
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          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/matrix-org/synapse/pull/14642"
        },
        {
          "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/"
        }
      ],
      "source": {
        "advisory": "GHSA-f3wc-3vxv-xmvr",
        "discovery": "UNKNOWN"
      },
      "title": "Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2023-32323",
    "datePublished": "2023-05-26T13:32:01.632Z",
    "dateReserved": "2023-05-08T13:26:03.880Z",
    "dateUpdated": "2025-02-13T16:50:32.310Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.