I visited www.webmail.us/testvirus and tried to send some viruses to my server. ClamAV failed to detect some of them, why?
Some messages will get through (24 and 25 ATM), but since they don’t contain any virus there’s nothing to find and therefore nothing to stop. By definition ClamAV only traps malicious code. “testvirus”:testvirus sends some messages which don’t contain any virus string, but only have some malformed MIME tags that can fool Outlook clients. It’s not an antivirus job to detect such messages.