m0leCon 2021 CTF Teaser - m0lang

Challenge

A friend of mine developed this brand new interpreter, do you want to play with it?

chall

Metadata

• Tags: reverse
• Author: matpro
• Points: 406
• Solves: 5

Solution

Solution: help "help"; flag;

The help text of the command help is longer than it seems, and it decrypts the flag too. After it’s decrypted, we have to retrieve it in the same command in order to avoid it being reset in refresh().

./chall 
m0lang 0.1 (May 14 2021, 19:00:00)
Type 'help "<command>"' or 'help <value>' for more information.
m0lang> help "help"; flag;
Really? You need help for help?
This is the flag: ptm{c4n_U_r34lly_1nt3rpret_Thi5_flag?}, now you can submit it!
m0lang> 

The flag is ptm{c4n_U_r34lly_1nt3rpret_Thi5_flag?}.