Rating:
# Autorev, Assemble! (225 solves)
>Clam was trying to make a neural network to automatically do reverse engineering for him, but he made a typo and the neural net ended up making a reverse engineering challenge instead of solving one! Can you get the flag?
>
>Find it on the shell server at /problems/2020/autorev_assemble/ or over tcp at nc shell.actf.co 20203.
>
>Author: aplet123
The main function looks obfuscated...
```c++
int __cdecl main(int argc, const char **argv, const char **envp)
{
puts("PROBLEM CREATION MODE: ON");
puts("VISUAL BASIC GUI: ON");
puts("HACKERMAN: ON");
puts("HOTEL: TRIVAGO");
puts("INPUT: ?");
fgets(z, 256, stdin);
if ( f992(z)
&& f268(z)
&& f723(z)
&& f611(z)
&& f985(z)
&& f45(z)
&& f189(z)
...
... // bunch of calls...
...
&& f915(z) )
{
puts("CHALLENGE: SOLVED");
}
else
{
puts("YOUR SKILL: INSUFFICIENT");
}
return 0;
}
```
Solution:
We use angr to automatically solve challenge for us :)
```python
import angr
import claripy
import sys
def main():
proj = angr.Project('autorev_assemble')
state = proj.factory.entry_state()
simgr = proj.factory.simgr(state)
simgr.explore(
find=0x408953,
avoid=0x408961
)
print(simgr)
if simgr.found:
f = simgr.found[-1]
print(f.posix.dumps(0))
if __name__ == "__main__":
sys.exit(main())
```
```bash
$ python3 solve.py
b'Blockchain big data solutions now with added machine learning. Enjoy! I sincerely hope you actf{wr0t3_4_pr0gr4m_t0_h3lp_y0u_w1th_th1s_df93171eb49e21a3a436e186bc68a5b2d8ed} instead of doing it by hand.'
```
