So any anti-virus software that detects a virus, and then bounces a reply back to the alleged "sender," with a warning about how their product stopped the virus, serves no purpose except to advertise their product.
Such emails are (1) unsolicited and (2) commercial, and are therefore spam.
Example of spam I received from a Sophos product:
The Hays Personnel Services Internet Gateway has detected a virus in an email message that you sent. The email has been quarantined and has not been delivered to its intended recipient(s) .
Please scan and clean all your files and attachments to ensure they are free of viruses and then re-send your message.
For your reference, the details of the message you sent are:
Date: Thu, 12 Feb 2004 11:20:25 +0800
The Virus Detected: Scenarios/Incoming/Incoming Sophos Virus Scan: A virus has been detected: 'W32/MyDoom-A'.
A number of current viruses spoof the senders email address. If this email has been sent to you in error please accept our apologies.
For further information on the virus specified above, please refer to http://www.sophos.com/ virusinfo/
Whoever wrote that software either knew or should have known that MyDoom spoofs the From line. Therefore, the only reason for sending that mail to me was to say "look how great Sophos is at protecting this company from viruses -- maybe it can protect your company too!" Ironically, that company offers anti-spam solutions as well!
I offer a warning to any company thinking about installing an anti-virus email filter -- if you pick a product that responds to viruses by sending spam, your company's mail server may well be blocked by other mail servers around the world. It's not fair, but that's the way the world works now.
To anyone who writes a review of anti-virus email software: warn your readers off any package which spams!
And to anti-virus companies who engage in this sleazy scam: screw you.