Investigate image metadata

Use command file image.png
Use command exiftool image.png
Use command xxd image.png
Use command strings image.png
Use tool binwalk to search binary images for embedded files and executable code: binwalk image.png
- To extract the file: binwalk -e image.png
Use command: steghide extract -sf image.png
Steganographic Decoder
- Upload the file to it
Bruteforce the password and extract contents of an image:

stegseek -sf image.png /path/to/wordlist
# Then if it extracts something do
file whatever.file # to know what is it

Use command steghide info image.png
Inspect audio files (like .wav files) with Sonic Visualizer
- Click on Layer > Add Spectrogram

Now set the scale to dB^2 and the colour to White on Black

Try with the tool outguess when you have an image
- Also there is this other project (manteined) outguess
- Then, install it with: ./configure && make
- Then, try the command: ./outguess -r /file/to/analyze /path/to/the/output
If you find a corrupted image (checking the file header of the image which should be \x89x50\x4Ex47), the try this command:

printf '\x89\x50\x4E\x47' | dd of=IMAGE.png bs=4 conv=notrunc
printf '\xff\xd8\xff\xe0' | dd of=IMAGE.jpg bs=4 conv=notrunc

If you have two strings in different formats, try this python script:

s1 = "44585d6b2368737c65252166234f20626d"
s2 = "1010101010101010101010101010101010"
h = hex(int(s1, 16) ^ int(s2, 16))[2:]
print(bytes.fromhex(h).decode('utf-8'))

You also have the tool stegsolve
- Install with:

wget http://www.caesum.com/handbook/Stegsolve.jar -O stegsolve.jar
chmod +x stegsolve.jar
mkdir bin
mv stegsolve.jar bin/

Use it with: java -jar stegsolve.jar
You might also need to search for a web in WaybackMachine
Open .pcap files with wireshark and analyze them
If you find a morse code on a .wav, try the tool morsecode decoder
If you find an image and running exiftool image.jpg you find some zip:

Do mv image.jp image.zip
Then unzip image.zip
Use Mnemonic to decode secrets hidden in images
- I put the source code with corrections in Mnemonic