CVE-2013-4983 in Web Protection Appliance
Summary
by MITRE
The get_referers function in /opt/ws/bin/sblistpack in Sophos Web Appliance before 3.7.9.1 and 3.8 before 3.8.1.1 allows remote attackers to execute arbitrary commands via shell metacharacters in the domain parameter to end-user/index.php.
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Analysis
by VulDB Data Team • 06/30/2024
The vulnerability identified as CVE-2013-4983 represents a critical command injection flaw within the Sophos Web Appliance software ecosystem. This vulnerability specifically targets the get_referers function located in the /opt/ws/bin/sblistpack component of the web appliance. The flaw exists in versions prior to 3.7.9.1 and 3.8 before 3.8.1.1, indicating a widespread issue affecting multiple release branches of the Sophos security appliance software. The vulnerability manifests when the end-user/index.php script processes the domain parameter, which is subsequently passed to the get_referers function without proper input sanitization or validation.
The technical exploitation of this vulnerability occurs through the injection of shell metacharacters within the domain parameter value. When attackers craft malicious input containing special shell characters such as semicolons, ampersands, or backticks, these characters are interpreted by the underlying shell executing the get_referers function. This allows remote attackers to execute arbitrary commands on the affected system with the privileges of the web server process. The vulnerability stems from insufficient input validation and improper sanitization of user-supplied data before it is processed by the system's shell execution mechanisms.
The operational impact of CVE-2013-4983 is severe and potentially catastrophic for organizations relying on Sophos Web Appliances for network security. Successful exploitation enables attackers to gain full command execution capabilities on the appliance, potentially leading to complete system compromise. Attackers could leverage this vulnerability to install backdoors, exfiltrate sensitive data, modify security policies, or use the compromised appliance as a pivot point for attacking internal network resources. The web appliance typically serves as a critical security gateway, making this vulnerability particularly dangerous as it could allow attackers to bypass security controls and gain unauthorized access to protected networks.
This vulnerability aligns with CWE-78, which specifically addresses "Improper Neutralization of Special Elements used in an OS Command" and represents a classic command injection attack vector. The flaw also maps to ATT&CK technique T1059.001, "Command and Scripting Interpreter: PowerShell", although the specific implementation involves shell command execution rather than PowerShell. Organizations should implement immediate mitigations including upgrading to the patched versions 3.7.9.1 and 3.8.1.1, implementing web application firewalls to filter malicious input patterns, and conducting thorough security assessments of the appliance configuration. Network segmentation and monitoring of suspicious command execution patterns should also be implemented as additional defensive measures against potential exploitation attempts.