CVE-2019-9161 in WLAN Controller
Summary
by MITRE
WAC on the Sangfor Sundray WLAN Controller version 3.7.4.2 and earlier has a Remote Code Execution issue allowing remote attackers to achieve full access to the system, because shell metacharacters in the nginx_webconsole.php Cookie header can be used to read an etc/config/wac/wns_cfg_admin_detail.xml file containing the admin password. (The password for root is the WebUI admin password concatenated with a static string.)
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Analysis
by VulDB Data Team • 09/04/2023
The vulnerability CVE-2019-9161 represents a critical remote code execution flaw in Sangfor Sundray WLAN Controller versions 3.7.4.2 and earlier, specifically affecting the Web Access Control (WAC) component. This issue stems from inadequate input validation within the nginx_webconsole.php script that processes Cookie headers, creating a path for remote attackers to exploit the system through maliciously crafted cookie values. The vulnerability manifests when shell metacharacters are present in the Cookie header, enabling attackers to manipulate the system's behavior and execute arbitrary commands with elevated privileges. The flaw is particularly dangerous because it provides attackers with full system access capabilities, effectively compromising the entire network infrastructure controlled by the vulnerable device.
The technical exploitation of this vulnerability occurs through the manipulation of the Cookie header in HTTP requests sent to the affected web console interface. When the nginx_webconsole.php script processes these cookies without proper sanitization, attackers can inject shell metacharacters that trigger unintended system behavior. This specific exploitation technique allows attackers to read sensitive configuration files, particularly the etc/config/wac/wns_cfg_admin_detail.xml file which contains administrative credentials. The extracted administrative password then serves as a foothold for further exploitation, as the root password is derived by concatenating the web UI admin password with a static string, making privilege escalation trivial for attackers who obtain the initial administrative credentials.
From an operational impact perspective, this vulnerability creates a severe security risk for organizations deploying Sangfor WLAN controllers in their network infrastructure. The remote code execution capability means attackers can perform complete system compromise without requiring physical access or local network presence, making it particularly attractive for sophisticated threat actors. The vulnerability affects the fundamental security posture of the network by allowing unauthorized individuals to gain administrative control over wireless access points and controllers, potentially enabling them to intercept network traffic, modify access policies, or establish persistent backdoors. Organizations using affected versions face the risk of complete network compromise, data breaches, and unauthorized access to sensitive network resources that the WLAN controller manages.
The vulnerability aligns with CWE-74 and CWE-94 categories from the Common Weakness Enumeration, representing weaknesses in data handling and code execution that allow for command injection attacks. From the MITRE ATT&CK framework perspective, this vulnerability maps to techniques such as T1210 (Exploitation of Remote Services) and T1078 (Valid Accounts) as attackers leverage the administrative credentials to gain persistent access. The attack chain typically begins with reconnaissance to identify vulnerable devices, followed by exploitation using crafted cookie values that trigger the command injection. The static string concatenation approach for root password derivation represents a predictable security flaw that significantly reduces the complexity of post-exploitation activities. Organizations should implement immediate mitigation strategies including patching to the latest software versions, network segmentation to limit access to affected devices, and enhanced monitoring for suspicious cookie header patterns that could indicate exploitation attempts. Additionally, regular security audits and vulnerability assessments should be conducted to identify similar weaknesses in other network infrastructure components and ensure comprehensive protection against similar attack vectors.