CVE-2020-14081 in TEW-827DRU
Summary
by MITRE
TRENDnet TEW-827DRU devices through 2.06B04 contain multiple command injections in apply.cgi via the action send_log_email with the key auth_acname (or auth_passwd), allowing an authenticated user to run arbitrary commands on the device.
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Analysis
by VulDB Data Team • 06/15/2020
The TRENDnet TEW-827DRU wireless router firmware version 2.06B04 and earlier contains critical command injection vulnerabilities that stem from improper input validation within the web interface's apply.cgi script. This vulnerability specifically affects the send_log_email action parameter when processing the auth_acname or auth_passwd keys, creating a pathway for authenticated attackers to execute arbitrary commands on the affected device. The flaw represents a significant security weakness that directly violates the principle of input sanitization and proper parameter handling in web applications.
The technical implementation of this vulnerability occurs through the web-based administration interface where the apply.cgi script fails to properly sanitize user-supplied input values before incorporating them into system commands. When an authenticated user submits data through the send_log_email functionality using either the auth_acname or auth_passwd parameters, the system directly appends these values to command strings without adequate validation or escaping mechanisms. This creates a classic command injection scenario where attacker-controlled input can manipulate the execution flow of system commands, potentially allowing full system compromise. The vulnerability falls under CWE-77 and CWE-94 categories, representing command injection and code injection weaknesses respectively, with the ATT&CK framework mapping this to T1059.001 for command and script injection techniques.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete control over the affected router. An authenticated user can leverage this vulnerability to execute arbitrary system commands with root privileges, potentially leading to persistent backdoor access, network reconnaissance, or further lateral movement within the network. The device becomes a potential pivot point for attackers to compromise other systems on the local network, as routers often serve as central points of connectivity. This vulnerability undermines the device's security posture and represents a critical weakness in the device's web interface security model, particularly concerning session management and input validation.
Organizations should immediately implement multiple layers of mitigation strategies to address this vulnerability. Firmware updates from TRENDnet should be prioritized and deployed across all affected devices, as the vendor has likely released patches to address the command injection flaws. Network segmentation and access control measures should be enforced to limit who can reach the device's web interface, while strict authentication controls and session management should be implemented. The principle of least privilege should be applied to web interface access, ensuring only authorized personnel can reach administrative functions. Additionally, network monitoring should be enhanced to detect suspicious command execution patterns, and regular security assessments should be conducted to identify similar vulnerabilities in other network devices. The vulnerability demonstrates the critical importance of input validation and proper command construction in web applications, particularly in network infrastructure devices where command injection can lead to complete system compromise.