Vulnerability Monitor

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CVE-2021-32785

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.

Published

2021-07-22T22:15:08.140

Last Modified

2024-11-21T06:07:44.050

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 5.3 (MEDIUM)

CVSSv2 Vector

AV:N/AC:M/Au:N/C:N/I:N/A:P

  • Access Vector: NETWORK
  • Access Complexity: MEDIUM
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: PARTIAL
Exploitability Score

8.6

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-134
  • Type: Primary
    CWE-134
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application openidc mod_auth_openidc < 2.4.9 Yes
Application apache http_server ≤ 2.4.48 No
Application netapp cloud_backup - Yes
Operating System debian debian_linux 10.0 Yes
References