Posted by Virus Bulletin on Nov 25, 2002
We examine ViraLock, a product which promises 'Zero Escape For Email Viruses', provided, it seems, the virus plays by their rules.
It's understandable that we greet announcements of 'magic pill' products with a little skepticism here at Virus Bulletin. ViraLock promises 'Zero Escape For Email Viruses' and claims to stop the spread of current and future email-borne viruses.
It seems at first that they may be onto something, but there are a few caveats (see below). The software works by sitting between your mail server and Outlook/Outlook Express, and 'encrypting' email addresses - presumably changing them for a key with which it looks up the real email address in its own database. In this way, even if you do get hit by a virus, all the addresses in your address book and mailbox folders will be these keys, and thus undeliverable, and you will not spread the virus.
However, there are some issues. First, how does the software determine between legitimate mail that the user is sending, and mail that Outlook is being compelled to send by a virus that's manipulating it using MAPI? One would assume it can't, and thus would be kind enough to decrypt the email addresses for the virus.
Secondly, this is the kind of product that will lull users into a false sense of security - people may begin to feel it's a replacement for regularly-updated anti-virus software, and thus get infected and hit with nasty payloads.
Finally, and most importantly, there are some situations in which the product would seem to fail.
Consider also W32/Ska - it works by hijacking WSOCK32.DLL. At the point of interception by the virus, the email address will need to have been decrypted - yet again, the virus isn't inhibited. Both Kakworm and Ska were fairly major viruses - they are both listed in the Top Ten Viruses in 'Computer viruses demystified' (published by a well-known vendor).