Vulnerability Description
mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. When mod_auth_openidc versions prior to 2.4.9 are configured to use an unencrypted Redis cache (`OIDCCacheEncrypt off`, `OIDCSessionType server-cache`, `OIDCCacheType redis`), `mod_auth_openidc` wrongly performed argument interpolation before passing Redis requests to `hiredis`, which would perform it again and lead to an uncontrolled format string bug. Initial assessment shows that this bug does not appear to allow gaining arbitrary code execution, but can reliably provoke a denial of service by repeatedly crashing the Apache workers. This bug has been corrected in version 2.4.9 by performing argument interpolation only once, using the `hiredis` API. As a workaround, this vulnerability can be mitigated by setting `OIDCCacheEncrypt` to `on`, as cache keys are cryptographically hashed before use when this option is enabled.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Openidc | Mod Auth Openidc | < 2.4.9 |
| Apache | Http Server | >= 2.0.0, <= 2.4.48 |
| Netapp | Cloud Backup | - |
| Debian | Debian Linux | 10.0 |
Related Weaknesses (CWE)
References
- https://github.com/zmartzone/mod_auth_openidc/commit/dc672688dc1f2db7df8ad4abebcPatchThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9Release NotesThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-55r8-6w97MitigationThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/04/msg00034.htmlMailing ListThird Party Advisory
- https://security.netapp.com/advisory/ntap-20210902-0001/Third Party Advisory
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatchThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/commit/dc672688dc1f2db7df8ad4abebcPatchThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9Release NotesThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-55r8-6w97MitigationThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/04/msg00034.htmlMailing ListThird Party Advisory
- https://security.netapp.com/advisory/ntap-20210902-0001/Third Party Advisory
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatchThird Party Advisory
FAQ
What is CVE-2021-32785?
CVE-2021-32785 is a vulnerability with a CVSS score of 5.3 (MEDIUM). mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. Wh...
How severe is CVE-2021-32785?
CVE-2021-32785 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-32785?
Check the references section above for vendor advisories and patch information. Affected products include: Openidc Mod Auth Openidc, Apache Http Server, Netapp Cloud Backup, Debian Debian Linux.