Archaic.md

Archaic

Description

The archaeological team at ångstromCTF has uncovered an archive from over 100 years ago! Can you read the contents?

Access the file at /problems/2021/archaic/archive.tar.gz on the shell server.

Author: kmh

Hint

What is a .tar.gz file?

Approach

I connected to the shell server to download the file locally using:

ssh shell.actf.co -l <teamname> cat "/problems/2021/archaic/archive.tar.gz" > archive.tar.gz

It prompted for the team password (which is found in the profile).

The hint suggests the file is actually a .tar.gz file but I decided to check anyways.

file archive.tar.gz

gave

archive.tar.gz: gzip compressed data, from Unix, original size modulo 2^32 10240

I used

gzip -d archive.tar.gz

which recovered the archive.tar file.

For whatever reason I was unable to untar the file in terminal (probably I'm just bad but shhhh). I used 7-Zip to open archive.tar which contains flag.txt.

Alternatively, Python could also have been used (make sure script is in the same directory):

import tarfile
tar = tarfile.open("archive.tar.gz")
tar.extractall()
tar.close()

Flag

actf{thou_hast_uncovered_ye_ol_fleg}