← Back to CTF Challenges
🖼️ Challenge #2: Hidden in Plain Sight
A threat actor is passing secret messages by hiding them inside innocent-looking images.
MEDIUM
🏆 100 points
Steganography
Image Analysis
LSB Technique
📖 Mission Briefing
Our threat intelligence unit intercepted network traffic containing a PNG image shared in an encrypted chat. On the surface, it looks like a normal landscape photo. However, we have strong reason to believe the sender used steganography to embed a hidden message using the LSB (Least Significant Bit) technique.
Your mission: Download the image, extract the hidden data using steganography tools, and recover the flag.
💡 Hint: Try using
steghide or zsteg to extract hidden data from the image. For steghide, the passphrase might be simpler than you think — try common words related to cybersecurity. You can also try online steganography tools.
🔧 Extra Hint: The passphrase is:
security. Run: steghide extract -sf secret_image.png -p security
📁 Challenge File
Download the image and extract the hidden message:
💻 Recommended tools: steghide, zsteg, Online Stego Decoder
🚩 Submit Your Flag
Found the flag? Enter it below. Format: PlainlySec{...}