CVE-2009-0545 in ZeroShell
Summary
by MITRE
cgi-bin/kerbynet in ZeroShell 1.0beta11 and earlier allows remote attackers to execute arbitrary commands via shell metacharacters in the type parameter in a NoAuthREQ x509List action.
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Analysis
by VulDB Data Team • 11/23/2024
The vulnerability identified as CVE-2009-0545 resides within the ZeroShell 1.0beta11 and earlier versions, specifically affecting the cgi-bin/kerbynet component. This represents a critical command injection flaw that enables remote attackers to execute arbitrary code on the affected system. The vulnerability manifests through the manipulation of the type parameter within the NoAuthREQ x509List action, which processes user input without proper sanitization or validation mechanisms. ZeroShell is a security-oriented Linux distribution designed for network security appliances, making this vulnerability particularly concerning for organizations relying on its network protection capabilities.
The technical exploitation of this vulnerability occurs through shell metacharacters embedded within the type parameter, which are then processed by the vulnerable application without adequate input filtering. This allows attackers to inject malicious shell commands that get executed with the privileges of the web server process. The flaw constitutes a classic command injection vulnerability, which maps to CWE-77 in the Common Weakness Enumeration catalog, specifically categorized as "Improper Neutralization of Special Elements used in a Command ('Command Injection'). The vulnerability exists due to insufficient validation of user-supplied input, creating an attack surface where malicious payloads can be interpreted as shell commands rather than mere data.
The operational impact of this vulnerability is severe and far-reaching for any organization utilizing affected ZeroShell versions. Remote attackers can gain complete control over the affected system, potentially leading to data breaches, system compromise, and unauthorized network access. The NoAuthREQ x509List action suggests this vulnerability affects certificate management functionality, which could allow attackers to manipulate digital certificates and potentially impersonate legitimate entities within the network. This capability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, enabling adversaries to execute malicious commands remotely without authentication. The vulnerability essentially provides a backdoor for attackers to establish persistent access and escalate privileges within the network infrastructure.
Mitigation strategies for CVE-2009-0545 should prioritize immediate patching of affected ZeroShell installations to version 1.0beta12 or later, where the vulnerability has been addressed through proper input validation and sanitization. Organizations should implement network segmentation to limit access to the vulnerable system and monitor for suspicious activities in the web server logs. Additional defensive measures include deploying web application firewalls that can detect and block malicious command injection attempts, implementing strict input validation at multiple layers, and conducting regular security assessments of network appliances. The vulnerability also highlights the importance of secure coding practices and input validation as fundamental security controls, particularly in applications handling user-supplied data in contexts where system commands may be executed. Organizations should also consider implementing principle of least privilege for web server processes to minimize potential damage from successful exploitation.