Use of Externally-Controlled Format String Affecting apache2-mod_auth_openidc package, versions <2.3.8-3.15.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.56% (78th percentile)

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  • Snyk IDSNYK-SLES152-APACHE2MODAUTHOPENIDC-2664306
  • published14 Apr 2022
  • disclosed13 Sept 2021

Introduced: 13 Sep 2021

CVE-2021-32785  (opens in a new tab)
CWE-134  (opens in a new tab)

How to fix?

Upgrade SLES:15.2 apache2-mod_auth_openidc to version 2.3.8-3.15.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream apache2-mod_auth_openidc package and not the apache2-mod_auth_openidc package as distributed by SLES. See How to fix? for SLES:15.2 relevant fixed versions and status.

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 Scores

version 3.1