Monday, July 29, 2013

MITRE 2013 Writeup : Binary 100

This one was actually broken and unsolvable for some time.  It was a Linux executable that displayed the following:

elliptic@elliptic:~/solved/bin100$ ./hello
Hello, World!
Don't forget the dash

Wow.  Uninformative.  Let's open it in GDB:

elliptic@elliptic:~/solved/bin100$ gdb --quiet hello
Reading symbols from /home/elliptic/solved/bin100/hello...(no debugging symbols found)...done.
(gdb) info fun
All defined functions:

Non-debugging symbols:
0x080482b8  _init
0x080482f0  puts
0x080482f0  puts@plt
0x08048300  __gmon_start__
0x08048300  __gmon_start__@plt
0x08048310  __libc_start_main
0x08048310  __libc_start_main@plt
0x08048320  _start
0x08048350  deregister_tm_clones
0x08048380  register_tm_clones
0x080483c0  __do_global_dtors_aux
0x080483e0  frame_dummy
0x0804840c  main
0x08048428  MCA02076b3d
0x08048450  __libc_csu_fini
0x08048460  __libc_csu_init
0x080484ba  __i686.get_pc_thunk.bx
0x080484c0  _fini

A basic look at the function list gives the key outright.  MCA-02076B3D

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