UTCTF 2025 Writeups

Forensics

Forgotten Footprints

Challenge: I didn’t want anyone to find the flag, so I hid it away. Unfortunately, I seem to have misplaced it.

Author: Caleb

we download the disk and inside it we find hex values we try to find the hex pattern of flag format or decode all the hexes in cyberchef

flag: utflag{d3l3t3d_bu7_n0t_g0n3_4ever}

Finally, an un-strings-able problem

Challenge:I inherited this really cursed disk image recently. All the files seem to be corrupted and I can’t even read some of them. What the heck is going on?

Author: Sasha

we start by sudo mount -o loop disk.img /mnt/chall/

Focusing on the challenge description, we realize that the challenge relates to some encoding of file permissions.

We try the following command to extract and decode permissions from binary:

ls -ltr /mnt/chall | awk '{print $1}' | tr "rwx" "1" | tr "-" "0" | awk '{print substr($0, 2)}' | tr -d "otal" | tr -d "\n" | fold -w8 | while read bin; do printf "\x$(printf '%x' $((2#$bin)))"; done

utflag{3xp3rt_f0r3ns1c_4n4lys1s_:3c}

nice chall !

flag: utflag{3xp3rt_f0r3ns1c_4n4lys1s_:3c}

OSINT

Three Words 1

Challenge: The three words I would use to describe this location are…

Flag format: utflag{word1.word2.word3}

Note: For the OSINT challenges, find the location where the photo was taken.

Author: Sasha

We are given this picture:

We start by analyzing it and observe a title at the bottom of the image: “Hackerman.” We search for “Hackerman building” and find that it is located at the University of Texas.

After locating the building, we determine that the photo was taken using a mirror, so it must be inside the Hackerman building. Using the what3words site, we find the exact location and retrieve the flag.

---

Three Words 2

Challenge: The three words I would use to describe this location are…

Flag format: utflag{word1.word2.word3}

Author: Sasha

We are given this image:

We notice that all three challenges are located at the University of Texas. By following the same approach as the first challenge and focusing on the traffic signs, we locate the place near the History Department.

---

Three Words 3

Challenge: The three words I would use to describe this location are…

Flag format: utflag{word1.word2.word3}

Author: Sasha

Similar to the previous challenges, we are given this picture:

By focusing on the traffic signs with a “K” letter, we locate the place behind the Littlefield House.