Source: disclosure@vulncheck.com
Gargoyle router management utility versions 1.5.x contain an authenticated OS command execution vulnerability in /utility/run_commands.sh. The application fails to properly restrict or validate input supplied via the 'commands' parameter, allowing an authenticated attacker to execute arbitrary shell commands on the underlying system. Successful exploitation may result in full compromise of the device, including unauthorized access to system files and execution of attacker-controlled commands.
Gargoyle router management utility versions 1.5.x are vulnerable to authenticated OS command execution, allowing attackers to execute arbitrary commands on the device. This vulnerability, stemming from improper input validation in the /utility/run_commands.sh script, can lead to complete device compromise, including data theft and system control.
Step 1: Authentication: The attacker must first successfully authenticate to the Gargoyle router's management interface. This typically involves providing valid credentials (username and password).
Step 2: Payload Construction: The attacker crafts a malicious payload containing shell commands to be executed on the router. This payload is designed to achieve the attacker's objectives (e.g., reverse shell, data exfiltration, user creation).
Step 3: Payload Delivery: The attacker sends a specially crafted HTTP request to the /utility/run_commands.sh script, including the malicious payload within the 'commands' parameter. This parameter is used to pass commands to the script for execution.
Step 4: Command Execution: The /utility/run_commands.sh script receives the attacker's input and, due to the lack of input validation, directly executes the injected shell commands. The commands are executed with the privileges of the web server process.
Step 5: Post-Exploitation: The attacker's commands are executed, allowing them to gain control of the router. This can include establishing a reverse shell, downloading and executing malware, modifying system files, or gaining access to sensitive information.
The vulnerability lies within the /utility/run_commands.sh script of Gargoyle router management utility versions 1.5.x. The script fails to properly sanitize or validate the input provided through the 'commands' parameter. Specifically, the script likely directly executes the user-supplied input using a shell command execution function (e.g., system(), exec(), or similar). The lack of input validation allows an authenticated attacker to inject arbitrary shell commands. The root cause is a failure to implement proper input validation and output encoding, leading to command injection. The script likely concatenates user-controlled input directly into a shell command without escaping or filtering special characters. This allows an attacker to inject malicious commands, such as those to download and execute malware, exfiltrate data, or modify system configurations.
This vulnerability is attractive to a wide range of attackers, from opportunistic script kiddies to sophisticated threat actors. It could be leveraged by APTs for initial access or persistence. Specific APT groups are difficult to attribute without further information, but any actor seeking to compromise home or small business networks would find this vulnerability valuable. CISA KEV status is highly probable if this vulnerability is actively exploited.
Monitor web server logs for suspicious activity, such as unusual HTTP requests to /utility/run_commands.sh with the 'commands' parameter containing shell metacharacters (e.g., ;, |, &, $).
Analyze network traffic for unusual outbound connections from the router, especially to suspicious IP addresses or domains.
Inspect router configuration files for unauthorized changes or modifications.
Monitor for the creation of new user accounts on the router.
Implement file integrity monitoring to detect changes to critical system files.
Use a network intrusion detection system (NIDS) with signatures specifically designed to detect command injection attempts against Gargoyle routers.
Examine the router's process list for suspicious processes or command executions.
Upgrade to the latest version of Gargoyle router firmware that addresses the vulnerability. Check the manufacturer's website for updates.
If upgrading is not immediately possible, implement a Web Application Firewall (WAF) in front of the router's management interface to filter malicious requests.
Implement strong input validation and output encoding within the /utility/run_commands.sh script. Sanitize the 'commands' parameter to remove or escape any potentially dangerous characters or sequences.
Restrict access to the router's management interface to trusted IP addresses or networks.
Change the default administrator credentials and use strong, unique passwords.
Regularly audit the router's configuration and logs for any suspicious activity.
Consider disabling the 'run_commands.sh' functionality if not essential for router operation.