CVE-2009-2765 in DD-WRT
Summary
by MITRE
httpd.c in httpd in the management GUI in DD-WRT 24 sp1, and other versions before build 12533, allows remote attackers to execute arbitrary commands via shell metacharacters in a request to a cgi-bin/ URI.
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Analysis
by VulDB Data Team • 12/07/2024
The vulnerability identified as CVE-2009-2765 represents a critical command injection flaw within the management graphical user interface of DD-WRT firmware versions prior to build 12533. This issue specifically affects the httpd.c component responsible for handling web requests within the httpd service that serves the administrative web interface. The vulnerability stems from inadequate input validation and sanitization mechanisms within the CGI-bin URI handling functionality, creating an exploitable condition that allows remote attackers to inject and execute arbitrary shell commands on the affected device. The flaw exists in the management GUI implementation where user-supplied input is directly incorporated into shell commands without proper sanitization, making it susceptible to shell metacharacter exploitation.
This vulnerability operates at the intersection of multiple cybersecurity domains and can be classified under CWE-78 as "Improper Neutralization of Special Elements used in an OS Command." The attack vector involves sending specially crafted HTTP requests to the cgi-bin endpoint of the web interface, where the malicious input contains shell metacharacters such as semicolons, pipes, or other command chaining operators. When the httpd service processes these requests, it fails to properly escape or validate the input before passing it to underlying shell execution functions, resulting in unauthorized command execution. The exploitation mechanism leverages the fact that the web interface uses shell commands to process certain operations, creating a direct pathway for attackers to bypass authentication and gain full control over the device's command execution capabilities.
The operational impact of CVE-2009-2765 is severe and multifaceted, as it provides attackers with complete system compromise of affected DD-WRT devices. Once exploited, attackers can execute arbitrary commands with the privileges of the web server process, which typically runs with elevated permissions on the device. This allows for complete network access, modification of device configuration, installation of malicious software, and potential use as a pivot point for attacking other devices within the local network. The vulnerability affects a wide range of DD-WRT firmware versions, making it particularly dangerous as it impacts numerous devices that may be deployed in enterprise and home network environments. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring physical access to the device, significantly increasing the attack surface and potential impact.
Mitigation strategies for this vulnerability require immediate firmware updates to build 12533 or later versions where the command injection flaw has been addressed through proper input validation and sanitization. Network administrators should implement strict access controls and firewall rules to limit access to the management interface to trusted IP addresses only, reducing the exposure window for remote exploitation attempts. Additionally, monitoring network traffic for suspicious patterns and implementing intrusion detection systems can help identify potential exploitation attempts. Organizations should also consider disabling the web management interface when not actively needed, or using alternative secure management protocols such as SSH with proper authentication mechanisms. From an ATT&CK framework perspective, this vulnerability maps to T1059.001 for Command and Scripting Interpreter, and T1021.001 for Remote Services, as it enables both local and remote command execution capabilities that can be leveraged for further lateral movement and privilege escalation within compromised networks.