CVE-2019-13151 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 action set_sta_enrollee_pin_5g and the key wps_sta_enrollee_pin.
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Analysis
by VulDB Data Team • 10/15/2023
The vulnerability CVE-2019-13151 represents a critical command injection flaw in the TRENDnet TEW-827DRU wireless router firmware versions prior to 2.05B11. This issue resides within the apply.cgi web interface component that handles wireless configuration parameters. The vulnerability specifically targets the WPS (Wi-Fi Protected Setup) functionality where the router processes the action set_sta_enrollee_pin_5g and the key wps_sta_enrollee_pin parameters. The flaw allows authenticated attackers to inject arbitrary commands into the router's command execution pipeline, potentially enabling full system compromise.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the web application layer of the router's firmware. When the apply.cgi script processes the WPS-related parameters, it fails to properly escape or filter user-supplied input before incorporating it into system commands. This creates a classic command injection vector where malicious input can be interpreted by the underlying shell as executable commands rather than data. The vulnerability requires authentication since the affected CGI script only accepts requests from authenticated users, but once authenticated, an attacker can leverage this flaw to execute arbitrary commands with the privileges of the web server process.
From an operational impact perspective, this vulnerability presents a significant risk to network security as it allows attackers who have gained access to the router's web interface to execute commands on the underlying operating system. The compromised router could serve as a foothold for further network infiltration, enabling attackers to establish persistent backdoors, redirect traffic, or use the device as a launching point for attacks against other networked systems. The WPS functionality is particularly concerning since it's often enabled by default on many routers, making the attack surface broader than typical command injection vulnerabilities that require more specific conditions. This vulnerability aligns with CWE-77 and CWE-78 categories, specifically addressing command injection flaws where untrusted data is directly incorporated into command execution contexts.
The exploitation of this vulnerability follows patterns consistent with ATT&CK technique T1059.001 for command and scripting interpreter, where attackers leverage web application interfaces to execute system commands. Network defenders should recognize this as a critical vulnerability requiring immediate remediation, particularly in environments where wireless infrastructure is not properly segmented from critical network resources. The vulnerability demonstrates the importance of implementing proper input validation and output encoding in web applications, as well as the necessity of keeping firmware updated to address known security flaws. Organizations should prioritize patching affected devices and consider implementing network monitoring to detect anomalous command execution patterns that may indicate exploitation attempts.
The remediation approach for CVE-2019-13151 involves upgrading the firmware to version 2.05B11 or later, which contains the necessary patches to address the command injection vulnerability. Additionally, network administrators should implement network segmentation to limit access to router management interfaces, enforce strong authentication mechanisms, and regularly audit router configurations to ensure WPS functionality is disabled when not required. The vulnerability serves as a reminder of the critical importance of firmware security in IoT and networking devices, where outdated software can provide attackers with persistent access to network infrastructure.