The first thing I did after reading the description was use exiftool to see if there was anything interesting in the image’s metadata:
Exiftool
And as we can see, it specifies Poem:Crimson heart, vibrant and bold,.Hearts flutter at your sight..Evenings glow softly red,.Cherries burst with sweet life..Kisses linger with your warmth..Love deep as merlot..Scarlet leaves falling softly,.Bold in every stroke.. Initially, it doesn’t make much sense… but later I noticed that the uppercase letters form the phrase CHECK LSB. So I researched and found that it’s possible, through a steganography technique, to write messages in the LSB (Least Significant Bit). Let’s proceed to the exploitation phase.
🔬 Vulnerability Analysis
Potential Vulnerabilities
LSB Extraction
🎯 Solution Path
Exploitation Steps
Exploitation
The exploitation was quite simple, in fact, I used aperisolve by uploading the image, and I noticed that with zsteg it extracted a .text field containing a base64, so I decided to replicate the same process out of curiosity:
1
zsteg --lsb red.png
Zsteg
I extracted the base64 and decoded it, thus finding the flag.
Flag capture
Manual Flag
🛠️ Exploitation Process
Approach
The automatic exploit extracts the base64 from the LSB and performs the decode.
