CVE-2004-0096 in mod_python
Summary
by MITRE
Unknown vulnerability in mod_python 2.7.9 allows remote attackers to cause a denial of service (httpd crash) via a certain query string, a variant of CAN-2003-0973.
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Analysis
by VulDB Data Team • 09/04/2019
The vulnerability identified as CVE-2004-0096 represents a denial of service flaw within mod_python version 2.7.9, a popular Apache module that enables Python scripting capabilities for web applications. This issue manifests when remote attackers submit specifically crafted query strings that trigger unexpected behavior in the module's processing logic, ultimately leading to the httpd daemon crashing and rendering the affected web service unavailable to legitimate users. The vulnerability is classified as a variant of CAN-2003-0973, indicating a similar pattern of exploitation that has been previously documented in the security community. The flaw demonstrates how seemingly benign input processing can be exploited to disrupt critical web infrastructure components, highlighting the importance of robust input validation and error handling in server-side applications.
The technical root cause of this vulnerability lies in improper handling of malformed query strings within the mod_python module's request processing pipeline. When the module encounters a specially crafted query string, it fails to properly validate or sanitize the input before attempting to process it, leading to memory corruption or stack overflow conditions that cause the httpd process to terminate unexpectedly. This type of vulnerability typically falls under CWE-121, which encompasses buffer overflow conditions, or CWE-122, which addresses buffer overflows in heap-based memory management. The vulnerability's exploitation requires minimal privileges and can be executed remotely, making it particularly dangerous for web servers that are publicly accessible. The specific nature of the query string manipulation suggests that the module's internal parsing logic does not adequately protect against malformed input sequences that could cause the interpreter to behave unpredictably.
The operational impact of CVE-2004-0096 extends beyond simple service disruption, as it represents a potential vector for broader attacks that could be combined with other vulnerabilities to compromise entire web applications. Organizations running affected versions of mod_python face significant risk of service interruption that could affect business operations and user experience, particularly in environments where web applications are critical to business processes. The vulnerability's classification as a denial of service issue means that attackers can repeatedly exploit it to maintain service disruption, potentially causing cascading effects in systems that depend on the affected web services. From an attacker perspective, this vulnerability aligns with ATT&CK technique T1499.004, which involves network denial of service attacks, and demonstrates how legacy web server modules can contain critical security flaws that persist across multiple versions without proper patching.
Mitigation strategies for this vulnerability primarily focus on immediate remediation through software updates and patches provided by the mod_python development community and Apache project. Organizations should prioritize upgrading to patched versions of mod_python that address the specific input validation issues present in version 2.7.9, as well as implementing network-level protections such as web application firewalls that can detect and block suspicious query string patterns. Additionally, system administrators should consider implementing monitoring solutions that can detect httpd process crashes and automatically restart services to minimize downtime. The vulnerability serves as a reminder of the importance of maintaining up-to-date software components and implementing proper input validation practices in web applications, as recommended by security frameworks such as the OWASP Top Ten and NIST guidelines for secure coding practices. Organizations should also conduct thorough vulnerability assessments to identify other potentially affected modules and ensure comprehensive protection against similar attack vectors.