Want your antivirus software to swallow your computer whole? It’s easy. Use a decompression bomb.

Decompression bombs are hidden in compressed attachments, like ZIPs, PNGs and GIFs. Antivirus software that opens a file hiding a bomb gets the computer version of Prader-Willi disease. It’s forcefed to the bursting point. Gobbles up all your memory or disk space till your system upchucks.

Lots of antivirus makers are at risk. So far, AERAsec has discovered problems in releases by AMaViS, FRISK, H+BEDV, Kaspersky Labs, Network Associates, SOFTWIN, Sophos and Trend Micro. Others are yet to be tested.

So if you can’t trust the a/v software, what can you do? Best practice indicates that you should strip all files capable of unleashing trouble. It’s a pretty long list, but worth the effort.

If you must allow certain file types, feed email through a carefully designed spam and content appliance before submitting it to the antiviral stuff. That way the content filter will get a crack at cleaning up problems first… So they won’t hurt your antivirus software.