CVE-2014-0242 in mod_wsgi
Summary
by MITRE
mod_wsgi module before 3.4 for Apache, when used in embedded mode, might allow remote attackers to obtain sensitive information via the Content-Type header which is generated from memory that may have been freed and then overwritten by a separate thread.
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Analysis
by VulDB Data Team • 12/22/2024
The vulnerability identified as CVE-2014-0242 affects the mod_wsgi module version 3.4 and earlier when operating in embedded mode within the Apache web server environment. This issue represents a classic memory safety problem that can lead to information disclosure, where attackers can potentially extract sensitive data from memory locations that have been freed and subsequently overwritten by concurrent thread operations. The vulnerability specifically manifests through manipulation of the Content-Type header, which is generated using memory that may contain remnants of previously freed data structures.
The technical flaw stems from improper memory management practices within the mod_wsgi module's embedded execution context. When the module processes requests in embedded mode, it maintains memory structures that are allocated and deallocated during the request lifecycle. However, in multi-threaded environments where separate threads may overwrite freed memory locations, the Content-Type header generation process can inadvertently include data from these overwritten memory areas. This occurs because the module does not properly sanitize or validate the memory content before incorporating it into the HTTP response headers, creating a scenario where sensitive information from other processes or previously processed requests could be exposed.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially expose confidential data that was previously stored in the freed memory regions. Attackers can exploit this weakness by crafting specific requests that trigger the generation of Content-Type headers, thereby accessing memory that contains remnants of other sensitive data such as authentication tokens, session information, or application-specific variables. The vulnerability is particularly concerning in environments where mod_wsgi handles sensitive web applications, as it could enable attackers to reconstruct portions of confidential data that should no longer be accessible. This type of vulnerability aligns with CWE-248, which addresses "Uncaught Exception" scenarios where memory management errors can lead to information exposure, and it maps to ATT&CK technique T1552.001 for "Unsecured Credentials" through the potential exposure of authentication-related data.
Mitigation strategies for CVE-2014-0242 primarily involve upgrading to mod_wsgi version 3.4 or later, which includes proper memory management fixes that prevent the reuse of freed memory in header generation. Organizations should also implement comprehensive monitoring of their web server environments to detect unusual Content-Type header values that might indicate exploitation attempts. Additionally, system administrators should consider implementing thread isolation mechanisms or restricting the use of embedded mode in security-critical applications where the risk of memory corruption is elevated. The vulnerability demonstrates the importance of proper memory lifecycle management in multi-threaded web server modules and highlights the necessity of thorough testing in concurrent execution environments to prevent similar issues from manifesting in production systems.