Defcon 22 QUALS - Dosfun4u

The challenge's abstract is succinct but quite accurate:

dosfun4u
Welcome to DOS, this is going to suck.

We are given a tar.gz archive containing a bochs configuration file, bochsrc, and a raw disk image, dosfun4u.img.

Defcon 20 QUALS - urandom 300

Connect to the given host and port, with the provided password.

The problem is as follow:

  Here come 100000 uint16_t, please tell me how to sort them into
  ascending order by sending me pairs of indicies to exchange, one
  per line, in the format: <index1>:<index2>
  For example to exchange elements 123 and 9821 you should send:
  123:9821
  Valid indicies are in the range 0..99999 inclusive. Send a blank
  line when you are done. If you correctly sort the array in
  sufficiently few moves I will give you a key!
  You have about 10 seconds to finish, and a 5 minute wait between
  successive connections.

Defcon 20 QUALS - Grab Bag 200

We have a jpeg file and its __MACOSX AppleDouble encoded Macintosh friend:

• 115e0ba3c3d72647fcb9a53ae90e47a6.jpg
• __MACOSX/._115e0ba3c3d72647fcb9a53ae90e47a6.jpg

The second file tells us that the jpeg comes from http://ircimages.com/ircimages/1/1/115e0ba3c3d72647fcb9a53ae90e47a6.jpg

Defcon 20 QUALS - Forensics 400

Execute photorec on the memory dump:
$ photorec for400/memory.dmp
Scan for Intel/Whole Disk/Other

During the recovery, notice some gpg files recovered:
$ find . -name "*.gpg"
./recup_dir.5/f1459128.gpg

$ file ./recup_dir.5/f1459128.gpg
./recup_dir.5/f1459128.gpg: PGP key security ring

This seems very good!

Defcon 17 QUALS - Forensics 300

Question: say my name cuz i got pain when i tried to get gain.

File attached: a powerpoint presentation (this is forensics after all...)

The file contained slides with useless base64 comments and images which also contained useless base64 comments (cf. http://forensic-proof.com/archives/495).

Defcon 16 QUALS - Binary Leetness 400

We are provided with an unknown binary. We are informed that it is running on Kenshoto's server. The goal is to understand what this binary does, and use this knowledge on the Kenshoto FreeBSD 6.x server to get a secret key.