Level 4

Ptrace your way

Pass prints the password for the level you are on. Try to make it print the next level's password.
This time it is not so easy:
/semtex/semtex4: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically linked, for GNU/Linux 2.6.15, stripped

Tip :

Pass uses geteuid() to get its information.
Read man ptrace