CVE-2024-7158 in A3100R
Summary
by MITRE • 07/28/2024
A vulnerability was found in TOTOLINK A3100R 4.1.2cu.5050_B20200504. It has been declared as critical. This vulnerability affects the function setTelnetCfg of the file /cgi-bin/cstecgi.cgi of the component HTTP POST Request Handler. The manipulation of the argument telnet_enabled leads to command injection. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-272572. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 08/09/2024
This critical vulnerability resides within the TOTOLINK A3100R router firmware version 4.1.2cu.5050_B20200504 and represents a severe command injection flaw in the HTTP POST Request Handler component. The vulnerability manifests through the setTelnetCfg function located in the /cgi-bin/cstecgi.cgi file, where the telnet_enabled parameter serves as the attack vector. The flaw allows remote attackers to execute arbitrary commands on the affected device by manipulating the telnet_enabled argument, effectively bypassing authentication mechanisms and gaining unauthorized control over the network infrastructure.
The technical implementation of this vulnerability follows a classic command injection pattern where user-supplied input is directly incorporated into system commands without proper sanitization or validation. When an attacker sends a specially crafted HTTP POST request to the vulnerable endpoint, the telnet_enabled parameter is processed without adequate input filtering, enabling the execution of malicious commands with the privileges of the web server process. This type of vulnerability falls under CWE-77 according to the Common Weakness Enumeration catalog, which specifically addresses command injection vulnerabilities that occur when a program constructs a system command by concatenating untrusted input from an upstream component without proper validation or sanitization.
The operational impact of this vulnerability is substantial as it provides remote attackers with complete administrative control over the affected router, potentially enabling them to modify network configurations, intercept traffic, establish backdoors, or use the device as a pivot point for attacking other systems within the network. The vulnerability's remote exploitability means that attackers do not require physical access to the device, significantly expanding the attack surface and making it particularly dangerous in enterprise and residential network environments. According to ATT&CK framework category T1059, this vulnerability enables adversaries to execute code through command and script interpreters, while T1021.001 addresses the use of remote services for lateral movement, making this vulnerability a critical threat for network compromise.
Organizations and individuals should immediately implement mitigations including network segmentation to isolate affected devices, disabling unnecessary services such as telnet, and applying firmware updates if available from the vendor despite their lack of response to the disclosure. Network monitoring should be enhanced to detect suspicious HTTP POST requests targeting the vulnerable cgi-bin endpoint, and firewall rules should be configured to restrict access to the affected router's management interfaces. Additionally, regular security audits of network infrastructure should be conducted to identify similar vulnerabilities in other network devices, as this flaw demonstrates a pattern of inadequate input validation in web-based management interfaces that may affect other vendors and products within the same ecosystem.