Digital Overdose 2022 CTF Vault

Solution

This is a Linux ELF file which when execute ask for key.

To check its inner working lets open it with IDA.

Here we can see a list of character being assigned to side by side memory locations. these characters include curly braces and have all the characters for the flag format

DOCTF{}

And at the end string compare function copying two strings, I gives an idea that user input is being compared to an embedded string.

Lets put a breakpoint at “s1” and start debugging. and let the program arange strings for us.

now program will ask for Password you can provide it with any random one.

when program hits the breakpoint you can hover over the “s1” string and can see the glimpse of the flag

All we have to do now is open the location in new window and convert this data it into ASCII by pressing “a” for shortcut and we have our flag

DOCTF{H4CK3RPR00F}