StealthZapper is a less-detectable log wiper. It attempts to leave wtmp and utmp “cleaner” looking by not simply leaving a blank hole where the offending data was deleted from.
You can download it from the following link: https://packetstormsecurity.com/files/download/36644/szapper.c
Source: https://packetstormsecurity.com/files/36644/szapper.c.html