Ecosyste.ms: Advisories
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Security Advisories: GSA_kwCzR0hTQS12YzdqLWg4eGctZnY1eM4AA1Df
matrix-appservice-bridge doesn't verify the sub parameter of an openId token exhange, allowing unauthorized access to provisioning APIs
Impact
A malicious Matrix server can use a foreign user's MXID in an OpenID exchange, allowing a bad actor to impersonate users when using the provisioning API.
Details
The library does not check that the servername part of the sub
parameter (containing the user's claimed MXID) is the same as the servername we are talking to. A malicious actor could spin up a server on any given domain, respond with a sub
parameter according to the user they want to act as and use the resulting token to perform provisioning requests.
Workarounds
Disable the provisioning API. If the bridge does not use the provisioning API, you are not vulnerable.
Permalink: https://github.com/advisories/GHSA-vc7j-h8xg-fv5xJSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS12YzdqLWg4eGctZnY1eM4AA1Df
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: 9 months ago
Updated: 6 months ago
CVSS Score: 5.0
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
Identifiers: GHSA-vc7j-h8xg-fv5x, CVE-2023-38691
References:
- https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-vc7j-h8xg-fv5x
- https://github.com/matrix-org/matrix-appservice-bridge/commit/4c6723a5e7beda65cdf1ae5dbb882e8beaac8552
- https://nvd.nist.gov/vuln/detail/CVE-2023-38691
- https://github.com/advisories/GHSA-vc7j-h8xg-fv5x
Blast Radius: 13.4
Affected Packages
npm:matrix-appservice-bridge
Dependent packages: 9Dependent repositories: 488
Downloads: 2,172 last month
Affected Version Ranges: = 9.0.0, >= 4.0.0, < 8.1.2
Fixed in: 9.0.1, 8.1.2
All affected versions: 4.0.0, 4.0.1, 4.0.2, 5.0.0, 5.1.0, 6.0.0, 7.0.0, 8.0.0, 8.1.0, 8.1.1, 9.0.0
All unaffected versions: 0.1.0, 0.1.1, 0.1.2, 0.1.3, 0.1.4, 0.1.5, 0.3.0, 0.3.1, 0.3.2, 0.3.3, 0.3.4, 0.3.5, 0.3.6, 0.3.7, 1.0.0, 1.0.1, 1.1.1, 1.2.0, 1.2.1, 1.3.0, 1.3.1, 1.3.2, 1.3.3, 1.3.4, 1.3.5, 1.3.6, 1.3.7, 1.4.0, 1.6.0, 1.6.1, 1.7.0, 1.8.0, 1.8.1, 1.9.0, 1.9.1, 1.9.2, 1.10.0, 1.10.1, 1.10.2, 1.10.3, 1.11.0, 1.11.1, 1.12.0, 1.12.1, 1.12.2, 1.13.0, 1.13.1, 1.13.2, 2.0.0, 2.1.0, 2.2.0, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.6.0, 2.6.1, 2.7.0, 3.0.0, 3.1.0, 3.1.1, 3.1.2, 3.2.0, 8.1.2, 9.0.1, 10.0.0, 10.1.0