Fighting malware and spam

Zip bomb

Small file that expands dangerously

A zip bomb is a file compressed into some archive format - often, but not necessarily, zip - which expands to an enormous size when uncompressed. Often the bomb is in the form of a loop, with the file inside the archive in fact a link back up to the top level of the archive, which will thus continuously unpack itself until all space and resources on the system are exhausted.

Zip bombs can also cause problems for anti-malware software trying to scan inside them, again using up large amounts of system resources. Scanners should be able to spot a zip bomb attack and stop scanning after a certain level.