// For flags

CVE-2021-32791

Hardcoded static IV and AAD with a reused key in AES GCM encryption in mod_auth_openidc

Severity Score

5.9
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

mod_auth_openidc es un módulo de autenticación/autorización para el servidor HTTP Apache versión 2.x que funciona como OpenID Connect Relying Party, autenticando a usuarios contra un OpenID Connect Provider. En mod_auth_openidc versiones anteriores a 2.4.9, el cifrado AES GCM en mod_auth_openidc usa un IV estático y un AAD. Es importante corregirlo porque esto crea un nonce estático y como aes-gcm es un cifrado de flujo, esto puede conllevar a problemas criptográficos conocidos, ya que se está reutilizando la misma clave. A partir de la versión 2.4.9 esto ha sido parcheado para usar valores dinámicos mediante el uso de rutinas de cifrado AES cjose

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.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
Medium
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-05-12 CVE Reserved
  • 2021-07-26 CVE Published
  • 2024-04-10 EPSS Updated
  • 2024-08-03 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-323: Reusing a Nonce, Key Pair in Encryption
  • CWE-330: Use of Insufficiently Random Values
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Openidc
Search vendor "Openidc"
 Mod Auth Openidc
Search vendor "Openidc" for product "Mod Auth Openidc"
 < 2.4.9
Search vendor "Openidc" for product "Mod Auth Openidc" and version " < 2.4.9"
-
Affected
in Apache
Search vendor "Apache"
 Http Server
Search vendor "Apache" for product "Http Server"
 >= 2.0.0 <= 2.4.48
Search vendor "Apache" for product "Http Server" and version " >= 2.0.0 <= 2.4.48"
-
Safe
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 33
Search vendor "Fedoraproject" for product "Fedora" and version "33"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 34
Search vendor "Fedoraproject" for product "Fedora" and version "34"
-
Affected