Sign In with your
Trend Micro Account
Need Help?
Need More Help?

Create a technical support case if you need further support.

Nessus Vulnerability Scanner machines are getting detected as C&C call back server

    • Updated:
    • 2 Aug 2021
    • Product/Version:
    • Apex One 2019
    • Platform:
    • N/A N/A

Nessus Vulnerability Scanners are falsely being detected by the Apex One agent as C&C callback servers even though these vulnerability scanners are authorized to do the said scanning activities. This article will guide you on how to address Apex One’s C&C false positive alerts triggered by vulnerability scanner tools like Nessus Vulnerability Scanner.


Vulnerability scanning tools (e.g. Nessus vulnerability scanner) normally send network vulnerability-related traffic to check if a machine is susceptible to a vulnerability. This behavior can trigger one of Apex One’s network security protection feature, “Suspicious Connection Service“ which checks for suspicious network packet and flags it as potential C&C callback.

In such scenario, Nessus Vulnerability Scanner can falsely be detected as C&C since it sends vulnerability-related traffic as part of its normal function. The unwanted detection can either trigger unnecessary alerts from trusted source and can also cause disruption of its function if suspicious connection action is set to block.

You can configure suspicious connection setting to either log or block the detected traffic. For more information, you may refer to the KB article on Blocking/Logging C&C IP connection in Apex One.

Here are the recommended steps to address C&C false alarm detection triggered by suspicious connection:

  1. Confirm if the Callback Address is coming from the Vulnerability Scanner Machine.
    If internal machines are being flagged as C&C server but do not have similar function as vulnerability scanning tools, further investigation should be conducted for potential malware infection (e.g. collect suspicious files and system information using ATTK, and submit the result to Trend Micro Technical Support for analysis.).

    Refer to this article on Generating and Exporting Logs in Apex One.


  2. Once Callback Address machine is verified as vulnerability scanner and is authorized to perform such activity, add the machine’s IP address in the Global User-defined IP List Settings under Approved lists. You may refer to this article on configuring global user-defined IP list settings.
Configure; Remove a Malware / Virus
Solution Id:
Did this article help you?

Thank you for your feedback!

*This form is automated system. General questions, technical, sales, and product-related issues submitted through this form will not be answered.

If you need additional help, you may try to contact the support team. Contact Support

To help us improve the quality of this article, please leave your email here so we can clarify further your feedback, if neccessary:
We will not send you spam or share your email address.

*This form is automated system. General questions, technical, sales, and product-related issues submitted through this form will not be answered.