Dealing with the false positive problem of a Webshell Trojan interception system involves balancing security detection accuracy with minimizing legitimate traffic or files being incorrectly flagged as malicious. False positives occur when the system mistakenly identifies benign files or scripts as Webshells, which can disrupt normal website operations and waste administrative resources.
Enhance the detection engine by using more advanced and precise analysis techniques, such as:
Example: A PHP file containing the function eval() might be flagged as suspicious. However, if it's part of a legitimate CMS plugin (e.g., WordPress), it may not be malicious. A better system would analyze how and where eval() is used before triggering an alert.
Maintain a whitelist of trusted files, directories, IP addresses, or users that are known to be safe. This reduces the chance of false positives for known-good content.
Example: If your website uses a third-party library that triggers a Webshell detection rule due to certain function usage, add that library’s file hash or path to the whitelist.
Customize and fine-tune the interception rules based on your specific environment. Avoid overly broad or generic rules that may catch benign behavior.
Example: Instead of blocking all usage of system() function, restrict the rule to only flag its usage in unexpected locations or when combined with other suspicious patterns.
Compare file hashes against known-good versions (e.g., original installation files). If a file hasn’t changed and matches a known-good hash, it’s less likely to be a Webshell.
Example: After deploying a web application, store the hash values of core files. Any modification to those files can then be investigated more carefully instead of triggering an automatic block.
Incorporate a manual review process or alert triage system where security analysts can verify suspicious files before taking action.
Example: When the system detects a potential Webshell, instead of blocking it immediately, quarantine the file and notify the administrator for review.
Log all interception events and use feedback to improve the system. If a false positive is identified, feed that information back into the model or rule set to reduce similar errors in the future.
Example: If a JavaScript file is falsely flagged, tag it as a false positive in the system so the same pattern is less likely to trigger again.
Recommended Tencent Cloud Services:
To enhance your Webshell detection and reduce false positives, consider using Tencent Cloud Web Application Firewall (WAF) and Host Security (Tencent Cloud Host Security, also known as CWP - Cloud Workload Protection).
Tencent Cloud WAF provides advanced protection against Webshells and other web attacks using both signature-based and behavior-based analysis. It allows rule customization and integrates with threat intelligence.
Tencent Cloud Host Security offers real-time monitoring, vulnerability management, and malicious file detection on servers. It uses machine learning to improve detection accuracy and reduce false positives. It can automatically isolate suspicious files and provide detailed forensic data for review.
These services help you respond quickly to real threats while minimizing disruption caused by false alarms.