This issue has been fixed as of version 5.73! This document applies to installations with version 5.72 and below.
The malware scanner in Security Ninja contains a few small snippets of malware and virus. These snippets are harmless and are just a tiny fraction of the malicious code where they were taken from.
The plugin uses these snippets to help scan for and identify malicious code on your website.
Unfortunately, these snippets trigger other virus scanners that will either warn or completely block the whole plugin.
Future versions of Security Ninja will include these snippets in a different way that prevents the virus scanners from detecting the snippets.
For now, if you are stuck with this problem, please create a support ticket and we can send you a .zip of the plugin without the snippets that you can install.
A sample from VirusTotal that was detected