CVE-2005-2091 in WebSphere Application Server
Summary
by MITRE
IBM WebSphere 5.1 and WebSphere 5.0 allows remote attackers to poison the web cache, bypass web application firewall protection, and conduct XSS attacks via an HTTP request with both a "Transfer-Encoding: chunked" header and a Content-Length header, which causes WebSphere to incorrectly handle and forward the body of the request in a way that causes the receiving server to process it as a separate HTTP request, aka "HTTP Request Smuggling."
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Analysis
by VulDB Data Team • 03/23/2017
The vulnerability described in CVE-2005-2091 represents a critical HTTP request smuggling flaw affecting IBM WebSphere Application Server versions 5.0 and 5.1. This security issue arises from the server's improper handling of HTTP requests that contain both Transfer-Encoding: chunked and Content-Length headers simultaneously. The flaw allows remote attackers to manipulate the HTTP request processing pipeline in a manner that creates confusion between different request boundaries, enabling malicious actors to exploit this behavior for various attack vectors.
The technical implementation of this vulnerability stems from WebSphere's inconsistent interpretation of conflicting HTTP headers. When a request contains both headers, the server fails to properly validate or normalize the request structure, leading to a scenario where the chunked transfer encoding is processed while the Content-Length header is also present. This creates a parsing ambiguity that can be exploited to inject malicious content into the web cache or bypass security mechanisms such as web application firewalls. The vulnerability specifically targets the HTTP request parsing logic within the application server's core processing components.
The operational impact of this vulnerability extends beyond simple cache poisoning to encompass sophisticated attack scenarios including cross-site scripting exploitation and firewall bypass techniques. Attackers can leverage this flaw to inject malicious payloads that get cached by the web server, potentially affecting multiple users who subsequently access the cached content. Additionally, the vulnerability enables attackers to circumvent web application firewall protections by crafting requests that appear legitimate to the firewall but are processed differently by the backend server, effectively allowing malicious requests to slip through security controls undetected.
This vulnerability directly maps to CWE-444, which describes "Inconsistent Interpretation of HTTP Requests" and aligns with ATT&CK technique T1190, "Exploit Public-Facing Application." The flaw demonstrates how HTTP protocol implementation inconsistencies can create attack surfaces that enable multiple security bypasses. Organizations running affected WebSphere versions face significant risk as this vulnerability can be exploited without authentication and can be automated, making it particularly dangerous in production environments where web applications handle sensitive data and user interactions.
The recommended mitigations for this vulnerability include immediate patching of affected WebSphere versions to address the HTTP request parsing logic, implementing proper header validation at the network level, and configuring application firewalls to detect and block requests containing conflicting Transfer-Encoding and Content-Length headers. Organizations should also consider implementing additional monitoring and logging to detect anomalous request patterns that might indicate exploitation attempts. Due to the age of the affected versions, organizations should prioritize migrating to supported WebSphere releases that have addressed this fundamental HTTP processing flaw.