Source: cve@mitre.org
AnyForm CGI remote execution.
AnyForm CGI is vulnerable to remote code execution, allowing attackers to execute arbitrary commands on the server. This vulnerability, dating back to the late 90s, poses a significant risk of complete system compromise and data exfiltration if unpatched.
Step 1: Target Identification: The attacker identifies a web server running AnyForm CGI.
Step 2: Payload Crafting: The attacker crafts a malicious payload, typically a shell command designed to execute arbitrary code on the server. This payload is often injected into a form field.
Step 3: Payload Delivery: The attacker submits the crafted payload through a specially constructed HTTP request to the AnyForm CGI script.
Step 4: Vulnerability Trigger: The AnyForm CGI script processes the submitted form data. Due to insufficient input validation, the malicious payload is interpreted as a command.
Step 5: Command Execution: The server executes the attacker's injected command, granting the attacker control over the server's resources.
Step 6: Post-Exploitation: The attacker can now execute further commands, potentially leading to data theft, system compromise, or lateral movement within the network.
The root cause lies in the AnyForm CGI script's failure to properly sanitize user-supplied input. Specifically, the script likely processes form data without validating the contents or length of input fields. This allows an attacker to inject malicious commands, such as shell commands, into form fields. When the script processes this data, it executes the attacker's commands on the server, resulting in remote code execution. The vulnerability is likely a form of command injection, where user-controlled data is directly passed to system commands without proper escaping or filtering.
While no specific APT groups are exclusively known for targeting this specific CVE, the ease of exploitation makes it a target for opportunistic attackers and botnets. This vulnerability is a classic example of a vulnerability that could be exploited by any attacker. CISA KEV: Not Listed.
Monitor web server logs for suspicious HTTP requests containing command injection payloads (e.g., shell metacharacters like ';', '|', '&', '$').
Analyze network traffic for unusual patterns, such as unexpected outbound connections from the web server.
Implement file integrity monitoring to detect unauthorized changes to system files.
Use a web application firewall (WAF) to filter malicious requests.
Look for unusual processes running on the server, especially those spawned by the web server user.
Patching: Apply the latest security patches for the AnyForm CGI script or any web server software that includes it. If the software is no longer supported, consider replacing it.
Input Validation: Implement robust input validation to sanitize all user-supplied data. This includes validating the data type, length, and format of all input fields.
Output Encoding: Encode output to prevent cross-site scripting (XSS) vulnerabilities.
Least Privilege: Run the web server with the least privileges necessary to perform its functions.
Web Application Firewall (WAF): Deploy a WAF to filter malicious traffic and block known attack patterns.
Regular Security Audits: Conduct regular security audits and penetration testing to identify and address vulnerabilities.
Disable Unused Features: Disable any unnecessary features or functionalities in the web application.