CVE-2005-1121 in Oops Proxy Server
Summary
by MITRE
Format string vulnerability in the my_xlog function in lib.c for Oops! Proxy Server 1.5.23 and earlier, as called by the auth functions in the passwd_mysql and passwd_pgsql modules, may allow attackers to execute arbitrary code via a URL.
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Analysis
by VulDB Data Team • 07/05/2021
The vulnerability identified as CVE-2005-1121 represents a critical format string flaw within the Oops! Proxy Server software ecosystem, specifically targeting version 1.5.23 and earlier installations. This security weakness exists within the my_xlog function located in the lib.c source file, which serves as a foundational logging component for the proxy server's operational activities. The flaw becomes particularly dangerous when triggered through authentication functions that are part of the passwd_mysql and passwd_pgsql modules, creating a direct attack vector that can be exploited by malicious actors to gain unauthorized system control.
The technical implementation of this vulnerability stems from improper handling of user-supplied input within the format string processing mechanism. When the my_xlog function processes logging information, it fails to properly validate or sanitize input parameters that are intended for format string operations. This oversight allows attackers to craft malicious URLs containing specially formatted input that can manipulate the printf-style function calls within the logging subsystem. The vulnerability manifests as a classic format string vulnerability, where attacker-controlled data can be interpreted as format specifiers, potentially leading to information disclosure, application crashes, or more critically, arbitrary code execution.
The operational impact of this vulnerability extends beyond simple privilege escalation or denial of service scenarios. Attackers can leverage this weakness to execute arbitrary code with the privileges of the proxy server process, potentially compromising the entire server infrastructure. The attack surface is particularly concerning given that the vulnerability is triggered during authentication processes, meaning that any user attempting to access protected resources through the proxy server could inadvertently trigger the exploit. This creates a persistent threat vector that remains active as long as the vulnerable proxy server version is operational, affecting both the confidentiality and integrity of the protected network resources.
The security implications of this vulnerability align with CWE-134, which specifically addresses format string vulnerabilities in software applications. This classification indicates that the flaw falls under the category of improper input validation and processing, where user-controllable data is directly used in format string operations without proper sanitization. The attack pattern closely follows techniques described in the MITRE ATT&CK framework under the T1059.007 sub-technique for command and scripting interpreter, as exploitation would likely involve injecting malicious code through the format string vulnerability. Organizations running affected versions of Oops! Proxy Server face significant risk of unauthorized access to their network resources, as the vulnerability can be exploited remotely without requiring prior authentication to the system itself.
Mitigation strategies for CVE-2005-1121 should prioritize immediate patching of the affected software to version 1.5.24 or later, which contains the necessary fixes for the format string vulnerability. System administrators should implement network segmentation to limit access to proxy server functions and consider implementing additional authentication layers to reduce the attack surface. Regular vulnerability scanning should be conducted to identify any remaining instances of the vulnerable software, while also monitoring for unusual logging patterns that might indicate exploitation attempts. The fix typically involves proper input validation and sanitization of user-supplied data before it is used in any format string operations, ensuring that the application treats all input as literal strings rather than executable format specifiers.