Ecosyste.ms: Advisories
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Security Advisories: GSA_kwCzR0hTQS05OHB4LTY0ODYtajdxY84AAzr1
Synapse has URL deny list bypass via oEmbed and image URLs when generating previews
Impact
A discovered oEmbed or image URL can bypass the url_preview_url_blacklist setting potentially allowing server side request forgery or bypassing network policies. Impact is limited to IP addresses allowed by the url_preview_ip_range_blacklist setting (by default this only allows public IPs) and by the limited information returned to the client:
- For discovered oEmbed URLs, any non-JSON response or a JSON response which includes non-oEmbed information is discarded.
- For discovered image URLs, any non-image response is discarded.
Systems which have URL preview disabled (via the url_preview_enabled setting) or have not configured a url_preview_url_blacklist are not affected.
Because of the uncommon configuration required, the limited information a malicious user, and the amount of guesses/time the attack would need; the severity is rated as low.
Patches
The issue is fixed by #15601.
Workarounds
The default configuration of the url_preview_ip_range_blacklist should protect against requests being made to internal infrastructure, URL previews of public URLs is expected.
Alternately URL previews could be disabled using the url_preview_enabled setting.
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS05OHB4LTY0ODYtajdxY84AAzr1
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Low
Classification: General
Published: 11 months ago
Updated: 6 months ago
CVSS Score: 3.5
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
Identifiers: GHSA-98px-6486-j7qc, CVE-2023-32683
References:
- https://github.com/matrix-org/synapse/security/advisories/GHSA-98px-6486-j7qc
- https://github.com/matrix-org/synapse/pull/15601
- https://github.com/matrix-org/synapse/releases/tag/v1.85.0
- https://nvd.nist.gov/vuln/detail/CVE-2023-32683
- https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2023-85.yaml
- https://lists.fedoraproject.org/archives/list/[email protected]/message/X6DH5A5YEB5LRIPP32OUW25FCGZFCZU2/
- https://github.com/advisories/GHSA-98px-6486-j7qc
Blast Radius: 5.0
Affected Packages
pypi:matrix-synapse
Dependent packages: 3Dependent repositories: 26
Downloads: 12,228 last month
Affected Version Ranges: < 1.85.0
Fixed in: 1.85.0
All affected versions: 0.33.5, 0.33.6, 0.33.7, 0.33.8, 0.33.9, 0.34.0, 0.99.0, 0.99.1, 0.99.2, 0.99.3, 0.99.4, 0.99.5, 1.0.0, 1.1.0, 1.2.0, 1.2.1, 1.3.0, 1.3.1, 1.4.0, 1.4.1, 1.5.0, 1.5.1, 1.6.0, 1.6.1, 1.7.0, 1.7.1, 1.7.2, 1.7.3, 1.8.0, 1.9.0, 1.9.1, 1.10.0, 1.10.1, 1.11.0, 1.11.1, 1.12.0, 1.12.1, 1.12.2, 1.12.3, 1.12.4, 1.13.0, 1.14.0, 1.15.0, 1.15.1, 1.15.2, 1.16.0, 1.16.1, 1.17.0, 1.18.0, 1.19.0, 1.19.1, 1.19.2, 1.19.3, 1.20.0, 1.20.1, 1.21.0, 1.21.1, 1.21.2, 1.22.0, 1.22.1, 1.23.0, 1.23.1, 1.24.0, 1.25.0, 1.26.0, 1.27.0, 1.28.0, 1.29.0, 1.30.0, 1.30.1, 1.31.0, 1.32.0, 1.32.1, 1.32.2, 1.33.0, 1.33.1, 1.33.2, 1.34.0, 1.35.0, 1.35.1, 1.36.0, 1.37.0, 1.37.1, 1.38.0, 1.38.1, 1.39.0, 1.40.0, 1.41.0, 1.41.1, 1.42.0, 1.43.0, 1.44.0, 1.45.0, 1.45.1, 1.46.0, 1.47.0, 1.47.1, 1.48.0, 1.49.0, 1.49.2, 1.50.0, 1.50.1, 1.50.2, 1.51.0, 1.52.0, 1.53.0, 1.54.0, 1.55.0, 1.55.1, 1.55.2, 1.56.0, 1.57.0, 1.57.1, 1.58.0, 1.58.1, 1.59.0, 1.59.1, 1.60.0, 1.61.0, 1.61.1, 1.62.0, 1.63.0, 1.63.1, 1.64.0, 1.65.0, 1.66.0, 1.67.0, 1.68.0, 1.69.0, 1.70.0, 1.70.1, 1.71.0, 1.72.0, 1.73.0, 1.74.0, 1.75.0, 1.76.0, 1.77.0, 1.78.0, 1.79.0, 1.80.0, 1.81.0, 1.82.0, 1.83.0, 1.84.0, 1.84.1
All unaffected versions: 1.85.0, 1.85.1, 1.85.2, 1.86.0, 1.87.0, 1.88.0, 1.89.0, 1.90.0, 1.91.0, 1.91.1, 1.91.2, 1.92.1, 1.92.2, 1.92.3, 1.93.0, 1.94.0, 1.95.0, 1.95.1, 1.96.1, 1.97.0, 1.98.0, 1.99.0, 1.100.0, 1.101.0, 1.102.0, 1.103.0, 1.104.0, 1.105.0