CVE-2010-3872 in Mod Fcgid
Summary
by MITRE
The fcgid_header_bucket_read function in fcgid_bucket.c in the mod_fcgid module before 2.3.6 for the Apache HTTP Server does not use bytewise pointer arithmetic in certain circumstances, which has unspecified impact and attack vectors related to "untrusted FastCGI applications" and a "stack buffer overwrite."
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Analysis
by VulDB Data Team • 10/05/2021
The vulnerability identified as CVE-2010-3872 resides within the mod_fcgid module of the Apache HTTP Server, specifically in the fcgid_header_bucket_read function located in fcgid_bucket.c. This flaw represents a critical security issue that affects versions prior to 2.3.6, where the module processes FastCGI applications through the Apache server. The vulnerability manifests when the function fails to employ proper bytewise pointer arithmetic during certain operational conditions, creating a dangerous scenario for system integrity and security.
The technical implementation of this vulnerability stems from improper memory handling within the FastCGI processing pipeline. When untrusted FastCGI applications interact with the Apache server through mod_fcgid, the fcgid_header_bucket_read function processes header data without adequate bounds checking or pointer arithmetic validation. This deficiency allows for potential stack buffer overflows when the function attempts to read header information from FastCGI responses, particularly when dealing with malformed or maliciously crafted input from untrusted sources.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it creates potential attack vectors that could be exploited by malicious actors. The unspecified nature of the impact suggests that the vulnerability may enable arbitrary code execution or privilege escalation depending on the specific circumstances of exploitation. Attackers could leverage this weakness by crafting specially designed FastCGI responses that trigger the vulnerable code path, potentially leading to complete system compromise when the Apache server processes these malicious inputs.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of improper pointer arithmetic leading to memory corruption. The ATT&CK framework categorizes this vulnerability under the T1059.007 technique for Command and Scripting Interpreter, as exploitation could enable attackers to execute arbitrary commands through compromised Apache processes. The vulnerability specifically targets the application layer of the OSI model, making it particularly dangerous in web server environments where multiple applications and users interact with the same infrastructure.
Mitigation strategies for CVE-2010-3872 primarily focus on immediate patching of affected Apache installations to version 2.3.6 or later, where the problematic pointer arithmetic has been corrected. Organizations should also implement network segmentation and access controls to limit exposure of vulnerable Apache servers to untrusted FastCGI applications. Additionally, monitoring systems should be configured to detect unusual FastCGI traffic patterns that might indicate exploitation attempts. Security teams should conduct thorough vulnerability assessments of their Apache installations and ensure that all mod_fcgid configurations properly validate input from FastCGI applications. The remediation process should include comprehensive testing to verify that the patch does not introduce compatibility issues with existing FastCGI applications while maintaining the security improvements necessary to prevent stack buffer overflows and related memory corruption attacks.