CVE-2019-13152 in TEW-827DRU
Summary
by MITRE
An issue was discovered in TRENDnet TEW-827DRU firmware before 2.05B11. There is a command injection in apply.cgi (exploitable with authentication) via the IP Address in Add Gaming Rule.
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Analysis
by VulDB Data Team • 10/15/2023
The vulnerability CVE-2019-13152 represents a critical command injection flaw in TRENDnet TEW-827DRU wireless router firmware versions prior to 2.05B11. This issue resides within the apply.cgi web interface component that processes user input for gaming rule configurations. The vulnerability specifically manifests when administrators attempt to add gaming rules to the router's firewall configuration, creating a dangerous pathway for malicious code execution. The flaw allows authenticated attackers to inject arbitrary commands through the IP Address field used in the Add Gaming Rule functionality, effectively bypassing the router's intended security boundaries.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the apply.cgi script. When users enter IP addresses for gaming rule configurations, the firmware fails to properly escape or filter special characters that could be interpreted as shell commands. This weakness falls under CWE-77 which specifically addresses command injection vulnerabilities where untrusted data is incorporated into system commands without proper validation. The vulnerability requires authentication since the apply.cgi interface typically requires administrative login credentials, but once authenticated, an attacker can leverage this flaw to execute arbitrary commands with the privileges of the web server process, which often runs with elevated system permissions.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to gain full control over the affected router's functionality. An authenticated attacker could potentially execute commands to modify firewall rules, redirect traffic, disable security features, or even install malicious firmware. The vulnerability affects the router's core network security functions, allowing attackers to compromise the entire network segment protected by the device. This aligns with ATT&CK technique T1059 which describes the use of command and scripting interpreters for execution, and T1068 which covers privilege escalation through exploitation of software vulnerabilities. The router's role as a network gateway makes this vulnerability particularly dangerous as it provides a potential entry point for lateral movement within corporate networks or for conducting man-in-the-middle attacks.
Mitigation strategies for CVE-2019-13152 primarily focus on firmware updates and network segmentation. TRENDnet released firmware version 2.05B11 to address this vulnerability, making immediate firmware upgrades the most effective defense mechanism. Network administrators should also implement strict access controls and limit administrative access to the router to only trusted personnel. Additional protective measures include disabling unnecessary services, implementing network monitoring to detect anomalous command execution patterns, and regularly reviewing firewall configurations for unauthorized changes. The vulnerability demonstrates the importance of input validation in web applications and highlights the need for robust security testing of embedded firmware systems, particularly those handling user input in privileged contexts. Organizations should also consider implementing network access control measures to prevent unauthorized access to administrative interfaces and maintain regular vulnerability assessments of network infrastructure devices.