CVE-2013-4286 in Communications Policy Management
Summary
by MITRE
Apache Tomcat before 6.0.39, 7.x before 7.0.47, and 8.x before 8.0.0-RC3, when an HTTP connector or AJP connector is used, does not properly handle certain inconsistent HTTP request headers, which allows remote attackers to trigger incorrect identification of a request's length and conduct request-smuggling attacks via (1) multiple Content-Length headers or (2) a Content-Length header and a "Transfer-Encoding: chunked" header. NOTE: this vulnerability exists because of an incomplete fix for CVE-2005-2090.
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Analysis
by VulDB Data Team • 09/27/2022
Apache Tomcat versions prior to 6.0.39, 7.x prior to 7.0.47, and 8.x prior to 8.0.0-RC3 contain a critical vulnerability in their HTTP request handling mechanisms that stems from an incomplete remediation of CVE-2005-2090. This vulnerability manifests when either HTTP connectors or AJP connectors process incoming requests with inconsistent header configurations, specifically involving Content-Length and Transfer-Encoding headers. The flaw arises from the server's inability to properly validate and interpret conflicting HTTP request headers, creating opportunities for attackers to manipulate request boundaries and potentially bypass security controls.
The technical implementation of this vulnerability exploits the inconsistent handling of HTTP headers by Tomcat's request parsing logic. When multiple Content-Length headers are present in a request, or when a single Content-Length header is combined with a Transfer-Encoding: chunked header, the server fails to properly resolve these contradictions. This inconsistency allows attackers to craft malicious requests where the server interprets different values for request length, leading to a state where the server processes only part of the request data while treating the remainder as a separate request. This fundamental parsing error creates a condition known as HTTP request smuggling, where attackers can manipulate how the server processes subsequent requests in the same connection.
The operational impact of this vulnerability extends beyond simple request processing errors and represents a significant security risk that can be exploited for various malicious activities. Attackers can leverage this vulnerability to perform request smuggling attacks that may result in cache poisoning, cross-site scripting attacks, or even authentication bypasses. The vulnerability is particularly dangerous because it can be exploited over both HTTP and AJP connectors, providing multiple attack vectors. The incomplete fix for CVE-2005-2090 suggests that previous security measures were insufficient to address all edge cases in header handling, leaving the system vulnerable to sophisticated attacks that exploit these specific header combinations.
This vulnerability maps directly to CWE-1295, which addresses improper handling of HTTP headers, and aligns with ATT&CK technique T1190 for exploiting vulnerabilities in web applications. The attack surface is broad since it affects multiple Tomcat versions and both connector types, making it particularly concerning for organizations running legacy systems. Organizations should prioritize immediate patching of affected versions to address this vulnerability. The mitigation strategy requires updating to patched versions of Tomcat where the header validation has been properly implemented to prevent inconsistent header processing. Additionally, network monitoring should be enhanced to detect unusual header patterns that might indicate exploitation attempts, and security teams should implement proper input validation at multiple layers of the application stack to reduce the attack surface.