Stego 100 - Perfect Concealment



Download file stg100.txt.
Notice there are weird uppercase letters in some words. Let's just extract these.

>>> ''.join(__import__('re').findall('\w\w*([A-Z])\w*', open("stg100.txt", "r").read()))
'FLAGISSEXYSTEGOPANDAS'

Flag: sexystegopandas

Stego 200 - Halloween



stg200.png Download file stg200.png

If we change the background color we can clearly see something like this:

..    . .. .  . .. ...  ... .   . ..... ..    . ..  ..  ...  . 
....... ....... ....... ....... ....... ....... ....... .......

..    . .. .  . ..  .   . ..... .. .... ..  ..  . ..... .. ... 
....... ....... ....... ....... ....... ....... ....... .......

.. .... . ..... ..  ... .. .    .. .... ...  .. ... .   ...  ..
....... ....... ....... ....... ....... ....... ....... .......

That's binary, let's extract the password from it:

>>> s="""1100001 1101001 1101110 1110100 1011111 1100001 1100110 1110010
... 1100001 1101001 1100100 1011111 1101111 1100110 1011111 1101110
... 1101111 1011111 1100111 1101000 1101111 1110011 1110100 1110011"""
>>> ''.join(chr(int(i, 2)) for i in s.replace("\n"," ").split(' '))
'aint_afraid_of_no_ghosts'

Flag: aint_afraid_of_no_ghosts

Stego 300 - Go Through the Tunnel



stg300.png Download file stg300.png
The text in the middle of the picture is a lure. THAT'S SO FUNNY.
Let's steganalyse this file more seriously, with StegSolve from Caesum (useful tool, although it's java).
stegsolve_lsb.png
Flag: 4E34B38257200616FB75CD869B8C3CF0