CVE-2006-6276 in One Application Server
Summary
by MITRE
HTTP request smuggling vulnerability in Sun Java System Proxy Server before 20061130, when used with Sun Java System Application Server or Sun Java System Web Server, allows remote attackers to bypass HTTP request filtering, hijack web sessions, perform cross-site scripting (XSS), and poison web caches via unspecified attack vectors.
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Analysis
by VulDB Data Team • 09/28/2017
The CVE-2006-6276 vulnerability represents a critical HTTP request smuggling flaw in Sun Java System Proxy Server versions prior to 20061130. This vulnerability specifically manifests when the proxy server operates in conjunction with Sun Java System Application Server or Sun Java System Web Server, creating a dangerous intersection of components that enables sophisticated attack vectors. The flaw stems from improper handling of HTTP requests that traverse the proxy infrastructure, allowing malicious actors to manipulate the request processing flow in ways that were not anticipated by the security design of these enterprise web infrastructure components.
The technical implementation of this vulnerability exploits inconsistencies in how the proxy server interprets and processes HTTP headers and request boundaries. When requests pass through the vulnerable proxy configuration, attackers can craft malicious HTTP requests that appear legitimate to the proxy server but are interpreted differently by the backend web server. This discrepancy creates a fundamental mismatch in request processing that enables attackers to inject arbitrary content or manipulate request parameters. The vulnerability operates at the HTTP protocol level, specifically targeting the way proxy servers handle chunked encoding, content-length headers, and request boundary detection mechanisms. According to CWE standards, this maps to CWE-444, which describes improper handling of HTTP requests, and represents a classic case of HTTP request smuggling as defined in the OWASP Top Ten security risks.
The operational impact of this vulnerability extends far beyond simple data interception or modification. Attackers leveraging this flaw can bypass critical HTTP request filtering mechanisms that are typically implemented to prevent malicious content from reaching backend applications. This bypass capability enables session hijacking attacks where malicious actors can impersonate legitimate users and gain unauthorized access to protected resources. The vulnerability also facilitates cross-site scripting attacks by allowing attackers to inject malicious scripts into web pages that are subsequently served to other users. Additionally, web cache poisoning becomes possible since the proxy server's inconsistent handling of requests can result in malicious content being cached and served to multiple users. The attack surface is particularly dangerous in enterprise environments where these proxy servers often serve as critical gateways between internal networks and external internet traffic, making the potential for widespread impact significant.
Organizations affected by this vulnerability should implement immediate mitigations including upgrading to the patched version of Sun Java System Proxy Server released after November 30, 2006, or applying the relevant security patches provided by Sun Microsystems. Network segmentation and additional monitoring of HTTP traffic patterns can help detect anomalous request behaviors that might indicate exploitation attempts. The implementation of web application firewalls and additional HTTP request validation mechanisms can provide additional layers of defense. From an ATT&CK framework perspective, this vulnerability aligns with techniques such as T1190 (Proxying) and T1566 (Phishing) where attackers leverage proxy infrastructure to establish persistent access points. Organizations should also consider implementing comprehensive logging and monitoring of proxy server activities, particularly focusing on unusual header combinations and request processing anomalies that could indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper HTTP protocol implementation in enterprise security infrastructure and highlights the need for thorough security testing of integrated systems rather than individual components.