CVE-2012-0053 in HTTP Server
Summary
by MITRE
protocol.c in the Apache HTTP Server 2.2.x through 2.2.21 does not properly restrict header information during construction of Bad Request (aka 400) error documents, which allows remote attackers to obtain the values of HTTPOnly cookies via vectors involving a (1) long or (2) malformed header in conjunction with crafted web script.
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Analysis
by VulDB Data Team • 06/19/2024
The vulnerability identified as CVE-2012-0053 resides within the Apache HTTP Server version 2.2.x through 2.2.21, specifically in the protocol.c component responsible for handling HTTP protocol operations. This flaw represents a critical information disclosure vulnerability that occurs during the construction of Bad Request error documents when the server encounters malformed or excessively long HTTP headers. The vulnerability exploits a weakness in how the server processes and sanitizes header information before incorporating it into error responses, creating an avenue for attackers to extract sensitive cookie values that should be protected by the HttpOnly flag.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the error handling mechanism of the Apache HTTP Server. When the server receives a request containing either a very long header field or a malformed header structure, it attempts to construct an error response that includes portions of the problematic header data. The protocol.c module fails to properly escape or filter this header information before embedding it into the 400 error document, allowing maliciously crafted header content to be reflected in the server's response. This reflection occurs in a manner that can be exploited by attackers to inject script code that can then access the browser's document.cookie object, thereby retrieving cookies marked with the HttpOnly attribute.
The operational impact of CVE-2012-0053 extends beyond simple information disclosure, as it directly undermines the security protections provided by the HttpOnly flag, which is a fundamental defense mechanism against cross-site scripting attacks. Attackers can leverage this vulnerability by crafting specific HTTP requests with malicious header content that, when processed by the vulnerable Apache server, results in the exposure of sensitive session cookies. This exposure enables attackers to perform session hijacking attacks, potentially gaining unauthorized access to user accounts and compromising the confidentiality of authenticated sessions. The vulnerability affects all versions of Apache HTTP Server 2.2.x through 2.2.21, representing a substantial attack surface across numerous deployed web server instances.
The exploitation of this vulnerability aligns with techniques described in the CWE-116 weakness category, which addresses improper encoding or escaping of output, and demonstrates how inadequate input validation can lead to information disclosure. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 (Phishing via Social Engineering) and T1566.002 (Phishing via Pretexting) as attackers can craft deceptive web content that exploits this vulnerability to obtain session tokens. Organizations should implement immediate mitigations including upgrading to Apache HTTP Server version 2.2.22 or later, which contains the necessary patches to properly sanitize header information during error document construction. Additional protective measures include implementing robust input validation at the network level, configuring web application firewalls to detect and block suspicious header patterns, and conducting regular security assessments to identify potentially vulnerable server configurations. The vulnerability also highlights the importance of proper error handling practices and demonstrates how seemingly innocuous error processing code can become a significant security risk when not properly secured against injection attacks.