CVE-2009-4769 in httpdx
Summary
by MITRE
Multiple format string vulnerabilities in the tolog function in httpdx 1.4, 1.4.5, 1.4.6, 1.4.6b, and 1.5 allow (1) remote attackers to execute arbitrary code via format string specifiers in a GET request to the HTTP server component when logging is enabled, and allow (2) remote authenticated users to execute arbitrary code via format string specifiers in a PWD command to the FTP server component.
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Analysis
by VulDB Data Team • 11/08/2025
The CVE-2009-4769 vulnerability represents a critical format string vulnerability affecting the httpdx web server software across multiple versions including 1.4, 1.4.5, 1.4.6, 1.4.6b, and 1.5. This vulnerability stems from improper handling of user-supplied input within the tolog function, which serves as the primary logging mechanism for both HTTP and FTP server components. The flaw exists when the application processes user-provided data without proper sanitization or validation, creating opportunities for malicious input to be interpreted as format specifiers rather than literal text. The vulnerability manifests in two distinct attack vectors that leverage different server protocols to achieve arbitrary code execution.
The technical implementation of this vulnerability occurs when the tolog function receives input from HTTP GET requests or FTP PWD commands and directly incorporates this data into format string operations without proper escaping or validation. When logging is enabled, the application passes user-supplied strings directly to printf-style functions, allowing attackers to inject format specifiers such as %x, %s, or %n that can read from or write to memory locations. This behavior violates fundamental security principles outlined in CWE-134, which specifically addresses the use of user-supplied format strings in printf functions. The vulnerability enables attackers to manipulate memory layout, potentially leading to stack corruption, information disclosure, or complete system compromise depending on the target environment.
The operational impact of CVE-2009-4769 is severe and multifaceted, affecting both remote unauthenticated and authenticated attack scenarios. Remote attackers can exploit the HTTP component by crafting malicious GET requests that contain format string specifiers, allowing them to execute arbitrary code on the target server without prior authentication. This represents a critical privilege escalation vector that can lead to complete system compromise and unauthorized access to sensitive data. Authenticated users can exploit the FTP component through PWD commands, demonstrating how vulnerabilities can be leveraged across different protocol interfaces within the same application. The vulnerability's impact aligns with ATT&CK technique T1059.007, which covers command and script injection attacks, and T1068, which addresses exploit for privilege escalation.
Mitigation strategies for CVE-2009-4769 must address both the immediate vulnerability and implement comprehensive security controls to prevent similar issues. Organizations should immediately apply patches or upgrades to httpdx versions that contain fixed implementations of the tolog function with proper input validation and sanitization. The recommended approach involves ensuring that all user-supplied input passed to format string functions undergoes proper escaping or is converted to literal strings before processing. Security controls should include implementing proper input validation at all entry points, disabling unnecessary logging features when not required, and monitoring for unusual patterns in log files that might indicate exploitation attempts. Additionally, organizations should implement network segmentation and access controls to limit exposure of vulnerable services, while following ATT&CK framework recommendations for detecting and preventing command injection attacks through network monitoring and intrusion detection systems.