Vulnerability · Published Jul 26, 2021 · Assigned by GitHub_M

CVE-2021-32791Hardcoded static IV and AAD with a reused key in AES GCM encryption in mod_auth_openidc

Medium 5.9

In plain English

A medium-severity weak randomness in mod_auth_openidc from zmartzone. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.5% (higher than 74% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)1.5%top 25.6% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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. 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:8cjose0.6.1-2.module_el8.6.0+2868+44838709ALSA-2022:1823
AlmaLinux:8cjose-devel0.6.1-2.module_el8.6.0+2868+44838709ALSA-2022:1823
AlmaLinux:8mod_auth_openidc2.3.7-11.module_el8.6.0+2868+44838709ALSA-2022:1823
Debian:12libapache2-mod-auth-openidc2.4.9-1DEBIAN-CVE-2021-32791
Debian:13libapache2-mod-auth-openidc2.4.9-1DEBIAN-CVE-2021-32791
Debian:14libapache2-mod-auth-openidc2.4.9-1DEBIAN-CVE-2021-32791
Rocky Linux:8cjose0:0.6.1-2.module+el8.3.0+129+2feafa46RLSA-2022:1823
Rocky Linux:8mod_auth_openidc0:2.3.7-11.module+el8.6.0+840+73eca44eRLSA-2022:1823

Affected products (as reported)

VendorProductVersions
zmartzone mod_auth_openidc < 2.4.9

Weakness: CWE-323, CWE-330 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

References