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Bandit Level 12 → 13

Shubham
Shubham
Cybersecurity Enthusiast

Login: ssh bandit12@bandit.labs.overthewire.org -p 2220
Password: 7x16WNeHIi5YkIhWsfFIqoognUTyj9Q4

task​

The password for the next level is stored in the file data.txt, which is a hexdump of a file that has been repeatedly compressed. For this level, it is helpful to create a directory under /tmp in which you can work.

theory lil bit​

  1. xxd: A tool that creates a hexdump of a given file or standard input. It can also do the reverse, which is what we need here using the -r flag to turn a hexdump back into a binary file.
  2. file: This command is your best friend here. It determines the file type by looking at the "magic bytes" (header) of the file, telling you if it's a Gzip, Bzip2, or Tar archive.
  3. Decompression Commands:
    • gzip/gunzip: Handles .gz files.
    • bzip2/bunzip2: Handles .bz2 files.
    • tar: Handles .tar files using -xf (extract file).
  4. Workflow: The process is iterative: check the file type with file, rename it to have the correct extension, decompress it, and repeat until you get ASCII text.

solution​

# Create a working directory
bandit12@bandit:~$ mktemp -d
/tmp/tmp.50qnmYRfkb
bandit12@bandit:~$ cd /tmp/tmp.50qnmYRfkb
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ cp ~/data.txt .

# Reverse the hexdump
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ xxd -r data.txt > binary

# Repeated decompression based on 'file' command output
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ file binary
binary: gzip compressed data...
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ mv binary b.gz && gunzip b.gz

bandit12@bandit:/tmp/tmp.50qnmYRfkb$ file b
b: bzip2 compressed data...
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ mv b file.bz2 && bunzip2 file.bz2

bandit12@bandit:/tmp/tmp.50qnmYRfkb$ file file
file: gzip compressed data...
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ mv file file.gz && gunzip file.gz

bandit12@bandit:/tmp/tmp.50qnmYRfkb$ file file
file: POSIX tar archive (GNU)
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ tar -xf file

bandit12@bandit:/tmp/tmp.50qnmYRfkb$ file data5.bin
data5.bin: POSIX tar archive (GNU)
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ tar -xf data5.bin

bandit12@bandit:/tmp/tmp.50qnmYRfkb$ file data6.bin
data6.bin: bzip2 compressed data...
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ mv data6.bin data.bz2 && bunzip2 data.bz2

bandit12@bandit:/tmp/tmp.50qnmYRfkb$ file data
data: POSIX tar archive (GNU)
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ tar -xf data

bandit12@bandit:/tmp/tmp.50qnmYRfkb$ file data8.bin
data8.bin: gzip compressed data...
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ mv data8.bin hello.gz && gunzip hello.gz

# Final Result
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ file hello
hello: ASCII text
bandit12@bandit:/tmp/tmp.50qnmYRfkb$ cat hello
The password is FO5dwFsc0cbaIiH0h8J2eUks2vdTDwAn

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