CVE-2021-32785

Severity CVSS v4.0:

Pending analysis

Type:

CWE-134 Format String Vulnerability

Publication date:

22/07/2021

Last modified:

30/01/2024

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. 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.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 7.50 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High

Base Score 3.x

7.50

Severity 3.x

HIGH

Vector 2.0

AV:N/AC:M/Au:N/C:N/I:N/A:P CVSS v2.0 Severity and Metrics:

Base Score: 4.30 MEDIUM
Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P

Attack Vector (AV): Network
Attack Complexity (AC): Medium
Authentication (Au): None
Confidentiality (C): None
Integrity (I): None
Availability (A): Physical

Base Score 2.0

4.30

Severity 2.0

MEDIUM

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:openidc:mod_auth_openidc::::::::		2.4.9 (excluding)
cpe:2.3:a:apache:http_server::::::::	2.0.0 (including)	2.4.48 (including)
cpe:2.3:a:netapp:cloud_backup:-:::::::*
cpe:2.3:o:debian:debian_linux:10.0:::::::*

To consult the complete list of CPE names with products and versions, see this page

CVE-2021-32785

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools