zzuf

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. Its main areas of use are:

quality assurance: use zzuf to test existing software, or integrate it into your own software’s testsuite security: very often, segmentation faults or memory corruption issues mean a potential security hole, zzuf helps exposing some of them code coverage analysis: use zzuf to maximise code coverage

zzuf’s primary target is media players, image viewers and web browsers, because the data they process is inherently insecure, but it was also successfully used to find bugs in system utilities such as objdump.

zzuf is not rocket science: the idea of fuzzing input data is barely new, but zzuf’s main purpose is to make things easier and automated. You can see an old, impressive list of bugs found with zzuf at http://caca.zoy.org/wiki/zzuf/bugs