Bug 1986395 (CVE-2021-32791) - CVE-2021-32791 mod_auth_openidc: hardcoded static IV and AAD with a reused key in AES GCM encryption
Summary: CVE-2021-32791 mod_auth_openidc: hardcoded static IV and AAD with a reused ke...
Alias: CVE-2021-32791
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1986396 1987216 1987217
Blocks: 1986104
TreeView+ depends on / blocked
Reported: 2021-07-27 12:51 UTC by Guilherme de Almeida Suckevicz
Modified: 2022-05-11 02:45 UTC (History)
5 users (show)

Fixed In Version: mod_auth_openidc 2.4.9
Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in mod_auth_openidc. The AES GCM encryption uses a static IV and AAD which could lead to other cryptographic attacks. The highest threat from this liability is to data confidentiality.
Clone Of:
Last Closed: 2022-05-11 02:45:34 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2022:1823 0 None None None 2022-05-10 13:39:59 UTC

Description Guilherme de Almeida Suckevicz 2021-07-27 12:51:45 UTC
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. In mod_auth_openidc before version 2.4.9, the AES GCM encryption in mod_auth_openidc uses a static IV and AAD. It is important to fix because this creates a static nonce and since aes-gcm is a stream cipher, this can lead to known cryptographic issues, since the same key is being reused. From 2.4.9 onwards this has been patched to use dynamic values through usage of cjose AES encryption routines.


Upstream patch:

Comment 1 Guilherme de Almeida Suckevicz 2021-07-27 12:52:12 UTC
Created mod_auth_openidc tracking bugs for this issue:

Affects: fedora-all [bug 1986396]

Comment 3 Riccardo Schirone 2021-08-06 13:01:37 UTC
Attack Complexity set to High (AC:H) because hacving a static IV does not immediately leads to a loss of confidentiality. An attacker needs to intercept some encrypted messages and then perform additional work to recover the original messages.

Comment 4 errata-xmlrpc 2022-05-10 13:39:56 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2022:1823 https://access.redhat.com/errata/RHSA-2022:1823

Comment 5 Product Security DevOps Team 2022-05-11 02:45:33 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


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