CVE-2012-10039 in ZEN Load Balancer
Summary
by MITRE • 08/11/2025
ZEN Load Balancer versions 2.0 and 3.0-rc1 contain a command injection vulnerability in content2-2.cgi. The filelog parameter is passed directly into a backtick-delimited exec() call without sanitation. An authenticated attacker can inject arbitrary shell commands, resulting in remote code execution as the root user. ZEN Load Balancer is the predecessor of ZEVENET and SKUDONET. The affected versions (2.0 and 3.0-rc1) are no longer supported. SKUDONET CE is the current community-maintained successor.
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Analysis
by VulDB Data Team • 08/11/2025
The CVE-2012-10039 vulnerability represents a critical command injection flaw in ZEN Load Balancer versions 2.0 and 3.0-rc1 that demonstrates fundamental security weaknesses in web application input validation and shell command execution practices. This vulnerability exists within the content2-2.cgi script where the filelog parameter is processed without proper sanitization before being passed into a backtick-delimited exec() function call. The flaw directly maps to CWE-77 which defines improper neutralization of special elements used in a command, creating an environment where malicious input can be executed as shell commands with the privileges of the web server process.
The technical exploitation of this vulnerability requires an authenticated attacker who can submit malicious input through the filelog parameter, which then gets directly incorporated into shell commands without any form of input validation or sanitization. This creates a remote code execution scenario where the attacker can execute arbitrary shell commands with root privileges, effectively compromising the entire system. The vulnerability is particularly dangerous because it operates at the system level rather than just the application level, allowing for complete system compromise including privilege escalation, data exfiltration, and potential lateral movement within a network.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential denial of service conditions. Attackers could leverage this vulnerability to install backdoors, modify system configurations, steal sensitive data, or use the compromised system as a launching point for attacks against other network resources. The fact that this vulnerability affects versions that are no longer supported means that organizations that have not migrated to current versions like SKUDONET CE remain at significant risk, as these legacy systems often contain other unpatched vulnerabilities that compound the security risk.
Organizations should immediately implement mitigations including immediate migration to supported versions of ZEN Load Balancer's successors such as SKUDONET CE or ZEVENET, which have addressed this and similar vulnerabilities through proper input validation and sanitization practices. Network segmentation and access control measures should be implemented to limit access to administrative interfaces, while regular security audits should be conducted to identify any remaining legacy systems that may be vulnerable to similar command injection flaws. The vulnerability also highlights the importance of following secure coding practices such as those outlined in the OWASP Secure Coding Practices and adheres to ATT&CK technique T1059.001 for Command and Scripting Interpreter, demonstrating how improper input handling can lead to complete system compromise.