CVE-2016-9682 in Secure Remote Access Server
Summary
by MITRE
The SonicWall Secure Remote Access server (version 8.1.0.2-14sv) is vulnerable to two Remote Command Injection vulnerabilities in its web administrative interface. These vulnerabilities occur in the diagnostics CGI (/cgi-bin/diagnostics) component responsible for emailing out information about the state of the system. The application doesn't properly escape the information passed in the 'tsrDeleteRestartedFile' or 'currentTSREmailTo' variables before making a call to system(), allowing for remote command injection. Exploitation of this vulnerability yields shell access to the remote machine under the nobody user account.
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Analysis
by VulDB Data Team • 07/04/2024
The SonicWall Secure Remote Access server represents a critical network security appliance that provides remote access and firewall capabilities for enterprise environments. This particular vulnerability affects version 8.1.0.2-14sv and demonstrates a fundamental flaw in input validation within the web administrative interface. The diagnostics CGI component serves as a legitimate system management function designed to email diagnostic information about system state, but this functionality becomes a vector for malicious exploitation due to improper sanitization of user-provided data. The vulnerability exists within the communication channel between the administrative web interface and the underlying operating system, creating a pathway for unauthorized code execution that bypasses normal security controls.
The technical implementation of this vulnerability stems from the application's failure to properly escape or validate user input before passing it to the system() function, which is a classic example of a command injection flaw categorized under CWE-77. The specific variables 'tsrDeleteRestartedFile' and 'currentTSREmailTo' serve as entry points where unescaped input directly translates into system commands, allowing attackers to execute arbitrary shell commands with the privileges of the nobody user account. This represents a privilege escalation issue where the attacker gains access to a system account with limited but still potentially dangerous capabilities, as the nobody account typically has minimal system permissions but can still access network services and potentially escalate privileges through additional attacks.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise potential. An attacker with access to the administrative web interface could leverage this vulnerability to gain persistent access to the network infrastructure, potentially leading to data exfiltration, lateral movement within the network, and disruption of critical services. The vulnerability affects organizations that rely on SonicWall appliances for remote access, making it particularly dangerous for companies with distributed workforces or remote access requirements. The fact that exploitation occurs through the web interface means that attackers could potentially leverage this vulnerability from external networks without requiring physical access or prior authentication credentials, making the attack surface significantly broader than typical internal vulnerabilities.
Mitigation strategies should include immediate patching of affected systems to address the command injection vulnerability through proper input validation and sanitization. Organizations should implement network segmentation to limit access to administrative interfaces and consider implementing additional monitoring for unusual email or system command execution patterns. The vulnerability demonstrates the importance of following secure coding practices such as those outlined in the OWASP Top Ten and MITRE ATT&CK framework, particularly in the area of command injection prevention. Network administrators should also consider implementing web application firewalls to detect and block malicious payloads targeting the affected CGI component, while maintaining comprehensive audit logging to detect exploitation attempts. The vulnerability highlights the critical need for regular security assessments and vulnerability management processes to identify and remediate similar issues before they can be exploited by threat actors.