CVE-2016-9554 in Web Appliance Remote
Summary
by MITRE
The Sophos Web Appliance Remote / Secure Web Gateway server (version 4.2.1.3) is vulnerable to a Remote Command Injection vulnerability in its web administrative interface. These vulnerabilities occur in MgrDiagnosticTools.php (/controllers/MgrDiagnosticTools.php), in the component responsible for performing diagnostic tests with the UNIX wget utility. The application doesn't properly escape the information passed in the 'url' variable before calling the executeCommand class function ($this->dtObj->executeCommand). This function calls exec() with unsanitized user input allowing for remote command injection. The page that contains the vulnerabilities, /controllers/MgrDiagnosticTools.php, is accessed by a built-in command answered by the administrative interface. The command that calls to that vulnerable page (passed in the 'section' parameter) is: 'configuration'. Exploitation of this vulnerability yields shell access to the remote machine under the 'spiderman' user account.
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Analysis
by VulDB Data Team • 05/16/2026
The vulnerability identified as CVE-2016-9554 affects the Sophos Web Appliance Remote and Secure Web Gateway server version 4.2.1.3, presenting a critical remote command injection flaw within its web administrative interface. This security weakness resides in the MgrDiagnosticTools.php file located at /controllers/MgrDiagnosticTools.php, which handles diagnostic testing functions utilizing the UNIX wget utility. The flaw stems from inadequate input sanitization when processing the 'url' parameter, creating a direct pathway for malicious command execution. The application's failure to properly escape user-supplied data before invoking the executeCommand class function creates an exploitable condition where unsanitized input flows directly into the exec() function, enabling arbitrary command execution on the target system.
The technical implementation of this vulnerability demonstrates a classic command injection flaw that aligns with CWE-77 and CWE-88 categories, specifically manifesting as CWE-78 which addresses improper neutralization of special elements used in OS commands. The attack vector operates through the administrative web interface where the vulnerable page is accessed via the 'section' parameter set to 'configuration'. When an attacker submits malicious input through the 'url' variable, the application processes this input without adequate sanitization or validation, allowing the attacker to inject OS commands that execute with the privileges of the 'spiderman' user account. This user context represents a significant operational risk as it provides access to system resources and potentially enables further privilege escalation or lateral movement within the network infrastructure.
The operational impact of this vulnerability extends beyond simple remote code execution, creating a comprehensive security breach that allows attackers to gain shell access to the affected appliance. The 'spiderman' user account typically possesses administrative privileges within the Sophos appliance environment, providing attackers with elevated access to network traffic monitoring capabilities, configuration changes, and potential access to sensitive data passing through the web gateway. This vulnerability directly maps to ATT&CK technique T1059.001 for command and script interpreter, specifically targeting the execution of malicious commands through the web interface. The implications include complete compromise of the web appliance, potential disruption of network security controls, and exposure of the internal network to further attacks.
Mitigation strategies for CVE-2016-9554 should prioritize immediate patching of the Sophos Web Appliance to version 4.2.1.4 or later, which contains the necessary security fixes. Network segmentation and firewall rules should be implemented to restrict access to the administrative web interface, limiting exposure to trusted administrative networks only. Input validation and sanitization measures must be strengthened throughout the application to prevent similar vulnerabilities in other components. Regular security assessments of web applications should include thorough review of parameter handling and command execution functions to identify potential injection points. The vulnerability also underscores the importance of principle of least privilege implementation, where administrative accounts should have minimal necessary permissions to reduce the impact of credential compromise. Organizations should implement intrusion detection systems to monitor for suspicious activity patterns associated with command injection attempts and maintain comprehensive audit logs for forensic analysis.