This rule is designed to detect potential server-side template injection (SSTI) vulnerabilities specifically within Velocity template rendering engines. The rule identifies exceptions that occur during the parsing and rendering of templates, particularly when user input is dynamically incorporated into templates, which can lead to remote code execution (RCE) vulnerabilities. The detection mechanism is reliant on application error logs, particularly those logged with a severity level of ERROR or above. Key exceptions associated with SSTI are monitored, including ParseErrorException, VelocityException, and TemplateInitException. These types of exceptions are indicative of template parsing failures that often stem from malicious input. To implement this rule effectively, it is critical that the application collects comprehensive error logs as specified in the log source definition. The goal is to preemptively identify and mitigate potential attacks before exploitation occurs.