A: Viruses can come into a system through many means: as a file, an attachment, a download from a website, encrypted, in a ZIP file, and in many other combinations. So how can you be sure your antivirus solution is able to catch them all?
You can test it. The security organization
EICAR maintains a test file that’s recognized by most antivirus applications as a test virus and is detected and stopped.
At EICAR’s download site you'll find that this test virus can be downloaded in various forms, such as over HTTP, over HTTPS, and in a ZIP file. It’s a great way to test your antivirus solution and its ability to detect viruses arriving through different means.