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VAULT_7A
Challenge Name: VAULT_7A
Category: Forensics / Steganography Author: Vishal V Difficulty: Easy
Challenge Description Within the Echo Maze, you discover a flickering hologram capsule labeled “VAULT_7A”. The projection stutters between timeframes, overlaying multiple moments into a single distorted image. Lyra’s voice echoes: “Some memories hide in layers… peel them back carefully.”
Downloads: temporal_fragment.jpg hint.txt
Solution: Initial Analysis Upon downloading the challenge files, I was presented with: A JPEG image file (temporal_fragment.jpg) A hint file (hint.txt)
First, I examined the basic file properties: bash: file temporal_fragment.jpg Output:temporal_fragment.jpg: JPEG image data, JFIF standard 1.01, aspect ratio, density 1x1, segment length 16, baseline, precision 8, 360x360, components 3 No immediate clue was found. From challenge description “…peel them back…” , we can infer it must be something related to steganography.
Tools Used: steghide - JPEG/BMP steganography tool base64 - Base64 decoder (built-in Linux/Mac command) zbarimg - QR code scanner (from zbar-tools package) Online Caesar cipher decoder (or manual decoding) Online QR scanner (https://webqr.com) as alternative
Step-by-Step Solution Step 1: Decode the Passphrase from hint.txt Reading the hint file revealed an encoded passphrase: bash: cat hint.txt
Key information found:
- Encoded passphrase: ALTWVYHS
- Hint: “Time shifts all things forward. To find truth, shift backwards 7 times.”
- Encryption method: TEMPORAL SHIFT PROTOCOL (Caesar/ROT cipher)
The hint indicates a Caesar cipher with shift of 7. To decrypt, I needed to shift each letter backward by 7 positions in the alphabet.
Manual decoding:
A - 7 = T L - 7 = E
T - 7 = M W - 7 = P V - 7 = O Y - 7 = R H - 7 = A S - 7 = L
Result: TEMPORAL Alternatively, using an online ROT decoder or Python: Python code: def rot_decode(text, shift): result = “” for char in text: if char.isalpha(): start = ord(‘A’) if char.isupper() else ord(‘a’) result += chr((ord(char) - start - shift) % 26 + start) else: result += char return result
print(rot_decode(“ALTWVYHS”, 7))
Output: TEMPORAL
Passphrase obtained: temporal Step 2: Check for any hidden images inside the given image: bash: steghide info temporal_fragment.jpg Output: steghide info temporal_fragment.jpg “temporal_fragment.jpg”: format: jpeg capacity: 634.0 Byte Try to get information about embedded data ? (y/n) y Enter passphrase: embedded file “qr_secret.png”: size: 481.0 Byte encrypted: rijndael-128, cbc compressed: yes Found a embedded file qr_secret.png!!
Step 3: Extract Hidden Data Using Steghide With the passphrase decoded, I used steghide to extract hidden data from the image: bash: steghide extract -sf temporal_fragment.jpg -p “temporal”
Output: wrote extracted data to “qr_secret.png” Success! The steghide tool extracted a hidden PNG file.
Step 4: Decode the QR Code Using zbarimg to scan the QR code: bash: zbarimg qr_secret.png ```
Output:
QR-Code:RkxBR3tFQ0hPX1ZBVUVUX01FTU9SWV9GUkFHTUVOVF83QV9SRVNUT1JFRH0= The QR code contained a base64-encoded string.
OR use a online qr decoder.
Step 5: Decode Base64 String The QR output was clearly base64 (ending with = padding). Decoding it: bash: echo “RkxBR3tFQ0hPX1ZBVUVUX01FTU9SWV9GUkFHTUVOVF83QV9SRVNUT1JFRH0=” | base64 -d Output: FLAG{ECHO_VAULT_MEMORY_FRAGMENT_7A_RESTORED}
Alternative Solution Paths Without Knowing the Password If the passphrase wasn’t decoded, players could use stegseek to brute-force it: bash# Install stegseek sudo apt-get install stegseek
Crack with common wordlist
stegseek temporal_fragment.jpg /usr/share/wordlists/rockyou.txt This would find “temporal” in seconds since it’s a common word.
Using Online Tools For players without CLI tools: Use online Caesar decoder: https://cryptii.com/pipes/caesar-cipher Extract with steghide (requires installation) Use online QR scanner: https://webqr.com Use online base64 decoder: https://www.base64decode.org
Flag
FLAG{ECHO_VAULT_MEMORY_FRAGMENT_7A_RESTORED}