Source: cna@vuldb.com
A flaw has been found in Vaelsys 4.1.0. This vulnerability affects unknown code of the file /tree/tree_server.php of the component HTTP POST Request Handler. This manipulation of the argument xajaxargs causes os command injection. The attack is possible to be carried out remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Vaelsys 4.1.0 is vulnerable to a critical remote command injection flaw. Successful exploitation allows attackers to execute arbitrary operating system commands on the server, potentially leading to complete system compromise and data exfiltration. The vendor has not addressed the vulnerability, increasing the risk of widespread exploitation.
Step 1: Payload Delivery: The attacker crafts a malicious HTTP POST request to /tree/tree_server.php.
Step 2: Parameter Injection: The attacker injects a malicious command (e.g., whoami, cat /etc/passwd) into the xajaxargs parameter of the POST request.
Step 3: Request Processing: The tree_server.php script receives the POST request and processes the xajaxargs parameter without proper sanitization.
Step 4: Command Execution: The injected command is passed to an operating system command execution function (e.g., exec(), system(), shell_exec()) without escaping or filtering.
Step 5: Command Execution and Response: The malicious command is executed on the server, and the results (e.g., user information, password file contents) are potentially returned to the attacker or used to further compromise the system.
The vulnerability lies within the /tree/tree_server.php file, specifically in how it handles the xajaxargs parameter within an HTTP POST request. The application fails to properly sanitize or validate user-supplied input within this parameter before passing it to a function that executes operating system commands. This lack of input validation allows an attacker to inject malicious commands into the xajaxargs parameter. When the server processes this input, the injected commands are executed with the privileges of the web server user, enabling full system control. The root cause is a missing or inadequate input validation mechanism, allowing for command injection.
Due to the ease of exploitation and the lack of vendor response, this vulnerability is likely to be targeted by a wide range of threat actors, including opportunistic attackers and potentially more sophisticated groups. There is no specific APT attribution available at this time. CISA KEV status: Not Applicable (as of this report).
Network traffic analysis: Monitor for unusual HTTP POST requests to /tree/tree_server.php with suspicious content in the xajaxargs parameter. Look for command injection attempts (e.g., use of semicolons, pipes, backticks, or other command separators).
Web server logs: Analyze web server access logs for POST requests to /tree/tree_server.php with unusually long or complex xajaxargs values. Examine error logs for signs of command execution failures or unexpected behavior.
Intrusion Detection/Prevention Systems (IDS/IPS): Deploy and configure IDS/IPS rules to detect command injection attempts based on known attack patterns and signatures.
File Integrity Monitoring (FIM): Monitor the /tree/tree_server.php file for unauthorized modifications.
Endpoint Detection and Response (EDR): Monitor server processes for suspicious command executions, especially those initiated by the web server user.
Input Validation: Implement strict input validation and sanitization for the xajaxargs parameter. This includes whitelisting allowed characters, escaping special characters, and limiting the length of the input.
Output Encoding: Properly encode output to prevent cross-site scripting (XSS) vulnerabilities if the application displays user-supplied data.
Least Privilege: Run the web server with the least privileges necessary to perform its functions. This limits the impact of a successful command injection attack.
Web Application Firewall (WAF): Deploy a WAF to filter malicious requests and block command injection attempts.
Regular Security Audits: Conduct regular security audits and penetration testing to identify and address vulnerabilities.
Patching: Although the vendor has not responded, if possible, attempt to patch the vulnerable code. If patching is not possible, consider removing the vulnerable component or disabling the functionality that uses the vulnerable code.