CVE-2022-39956 Explained : Impact and Mitigation
Learn about CVE-2022-39956 impacting OWASP ModSecurity Core Rule Set, allowing partial rule bypass for HTTP multipart requests using character encoding.
A detailed insight into the CVE-2022-39956 vulnerability affecting OWASP ModSecurity Core Rule Set.
Understanding CVE-2022-39956
This CVE involves a partial rule set bypass in OWASP ModSecurity Core Rule Set for HTTP multipart requests using character encoding in the Content-Type or Content-Transfer-Encoding header.
What is CVE-2022-39956?
The OWASP ModSecurity Core Rule Set (CRS) is impacted by a partial rule set bypass for HTTP multipart requests by submitting a payload that uses a character encoding scheme via the Content-Type or Content-Transfer-Encoding header fields. This payload will bypass detection, allowing potential exploitation on vulnerable backends that support these encoding schemes.
The Impact of CVE-2022-39956
The vulnerability affects legacy CRS versions 3.0.x and 3.1.x, as well as the currently supported versions 3.2.1 and 3.3.2. Users are advised to upgrade to versions 3.2.2 and 3.3.3 to mitigate these vulnerabilities.
Technical Details of CVE-2022-39956
A closer look at the vulnerability's description, affected systems and versions, and exploitation mechanism.
Vulnerability Description
The vulnerability allows a partial rule set bypass in OWASP ModSecurity CRS for multipart HTTP requests, facilitating payload submission with specific character encoding schemes that evade detection.
Affected Systems and Versions
OWASP ModSecurity Core Rule Set versions 3.0.x, 3.1.x, up to 3.2.1, and 3.3.2 are impacted by the vulnerability.
Exploitation Mechanism
By utilizing character encoding in the Content-Type or Content-Transfer-Encoding headers, malicious actors can evade detection and potentially exploit vulnerable backends.
Mitigation and Prevention
Effective steps to address CVE-2022-39956 and prevent potential security risks.
Immediate Steps to Take
Integrators and users are advised to upgrade to OWASP ModSecurity Core Rule Set versions 3.2.2 and 3.3.3 promptly to mitigate the vulnerability.
Long-Term Security Practices
Regularly updating and maintaining the latest ModSecurity versions (v2.9.6 / v3.0.8) can enhance long-term security against potential threats.
Patching and Updates
Stay informed about security updates and patches released by OWASP to address vulnerabilities like CVE-2022-39956.