Bug 2131315 (CVE-2022-39955)

Summary: CVE-2022-39955 mod_security_crs: Multiple charsets defined in Content-Type header
Product: [Other] Security Response Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: vulnerabilityAssignee: Nobody <nobody>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: athmanem, luhliari
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: mod_security_crs 3.2.2, mod_security_crs 3.3.3 Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in the OWASP ModSecurity Core Rule Set. A specially crafted HTTP Content-Type header field allows an encoded payload bypass detection, which may be decoded in the back-end application.
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 2131316, 2131341, 2131342    
Bug Blocks: 2128790    

Description Guilherme de Almeida Suckevicz 2022-09-30 16:52:51 UTC
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.


Comment 1 Guilherme de Almeida Suckevicz 2022-09-30 16:53:05 UTC
Created mod_security_crs tracking bugs for this issue:

Affects: fedora-all [bug 2131316]