zzuf is a transparent application input fuzzer. Its purpose is to
find bugs in applications by corrupting their user-contributed data
(which more than often comes from untrusted sources on the Internet).
It works by intercepting file and network operations and changing
random bits in the program's input. zzuf's behaviour is
deterministic, making it easier to reproduce bugs.

WWW:	http://sam.zoy.org/zzuf/