fix my pc
500 points
My boss’s computer died recently. We managed to dump some of the drive, but can’t figure out a way to unlock it. Download (233MB) https://cloudstor.aarnet.edu.au/plus/s/lIZ7mV36US93DhA
Solution
We start with rescue.zip with two files within: system.bin and crash.bin
The first one is disk image, the second one looks like memory dump.
I’ve started with mounting the disk.
modprobe nbd max_part=8
qemu-nbd –connect=/dev/nbd0 /<em>tmp</em>/system.bin
But I’ve been stopped by disk encryption.
Ok, let’s try to retrieve the key to decrypt those partitions (/dev/nbd0p1 was boot with nothing
interesting).
I downloaded findaes tool from
https://sourceforge.net/projects/findaes/ and used it to find
the keys in memory dump.
Looks like I’ve been lucky today ;-)
I’ve combined two parts of the key together and saved as binary.
echo 094e2adf58cfb17d85f0f6933f7b44efa00a3cda7bbe01873e09ff4ee7a60539ff98d76761147024ebb0c8d4e1141814214d2a83d7936609377755e5180a3c57 | xxd -r -p > /tmp/key
And then tried to use it.
cryptsetup luksAddKey /dev/nbd0p2 --master-key-file /tmp/key
cryptsetup luksOpen /dev/nbd0p2 rescue
lsblk
mount /<em>dev/mapper/rescue /mnt</em>
On mounted partition there were many files with corrupted names, but the content was ok and gave me the hint where’s the key for 2nd partition.
cryptsetup luksOpen /dev/nbd0p3 crypthome --key-file /mnt/etc/crypttab.d/home.key
Interesting parts were ssh keys and .ash_history
So I’ve used bob’s keys to clone the repo and have a look.
export GIT_SSH_COMMAND="ssh -o IdentitiesOnly=yes -i /mnt2/bob/.ssh/id_rsa"
git clone [email protected]:cornochips/configs
cd configs
Checked the content of files with no luck, then suddenly…
for i in `git log --all --oneline | awk -F ' ' '{print $1, $8}'`; do git diff ${i}; done
DUCTF{aTl3astIhadAB3ck8py4n63xOVX4A}
