01
May
2012

Plaid CTF 2012 – 80s Thinking

We saw two robots dressed in sweater dresses, leggings and press on nails and decided we had to listen in. But, these robots were speaking an unintelligible language. Can you figure out what they were saying?
Title: 80s Thinking (250)
Category: Practical Packets

In this challenge we received an audio file (80s.wav). Listening to the audio file we got the idea it might be a modem or fax connection, this also fits in with the challenge description.

We tried a lot of approaches including replaying the sound to a fax, however this did not resulting anything except Fax error reports.

After a while we found a tool which claimed to decode fax data from audio files. This tool can be found here: http://www.btt-int.com/products_faxsolutions_en.php.

Sadly enough the tool would not come up with a recovered fax after we let is parse the audio file. After trouble shooting for a while we found (by using audacity) that the file is Mono and 48000Hz. The tool we found did not accept 48000Hz input files so we had to convert the audio file to 8000Hz. After this conversion the tool would parse the audio file as can be seen in the tool screenshot below.

Sadly enough this software would only run in Demo mode and by doing so it would put large banners on top of the recovered fax image. The recovered fax image can be seen below.

With the information we could read from the fax we were able to guess the key for this challenge, which was: BlastFromThePast^_^

Comments are closed.