Crack IFS Writeup (Dawg CTF 2021)

09 May 2021

D4rkDemian

Type: Forensics

Difficulty: Easy

Prompt: The accounts in this QNX IFS have insecure passwords. Crack them to assemble the flag.

Solution

we were provided an .ifs file which is a file system image of a Blackberry device so we need to dump the image i used this github tool to dump the files dumpifs so i dumped using following command:

./dumpifs ../DawgCTF.ifs -d ../dump -x -b

On searching i found the shadow file in the dump and as from reading the prompt it is clear that the passwords are very weak… So i used John the ripper to crack the hash but firstly we need to create our own wordlist. On enumerating i found that all the passwords are 4 character long so i wrote a script to make a wordlist:

import string
s = string.printable
print(s)
with open("wordlist.txt","w") as f:
    letters = string.printable
    for i in letters:
        for j in letters:
            for k in letters:
                for l in letters:
                    word=i+j+k+l

                    f.write(word + '\n') 

Now i ran john john --rules shadow -w=wordlist.txt

And hence we got our flag!! DawgCTF{un_scramble}