Lookey here Description Attackers have hidden information in a very large mass of data in the past, maybe they are still doing it. Download the data here. Solving Download File Cat File | grep picoCTF* You also can grep directly with grep -o "picoCTF{.*}" Feel free to use the getflag script. #!/bin/bash echo "Getting flag for you…" grep -o "picoCTF{.*}"
File types Description This file was found among some files marked confidential but my pdf reader cannot read it, maybe yours can. You can download the file from here. Solving The file Flag.pdf isn’t a pdf file If you check it with file Flag.pdf, you’ll see, that it is a shell archive Flag.pdf: shell archive text If you execute this
Vigenere Description Can you decrypt this message? Decrypt this message using this key "CYLAB". Solving Lets use CyberChef for that. Copy the message into the input field and use Vigenère Decode The key is given Key: "CYLAB"
Substitution Challenges Because this challenges are all very similar, we will not describe them in own articles 🙂 . Solving Substitutions cypher replace the 26 letters of an alphabet with other letters (one letter matches only one other). If you can find out which letter was replaced with which letter, then you can crack this cypher relatively easily. The best
transposition-trial Description Our data got corrupted on the way here. Luckily, nothing got replaced, but every block of 3 got scrambled around! The first word seems to be three letters long, maybe you can use that to recover the rest of the message. Download the corrupted message here. Solving Looking into the encrypted message we can see, that the first
rail-fence Description A type of transposition cipher is the rail fence cipher, which is described here. Here is one such cipher encrypted using the rail fence with 4 rails. Can you decrypt it? Download the message here. Put the decoded message in the picoCTF flag format, picoCTF{decoded_message}. Solving So – there is everything we need to know in the challenge
diffie-hellman Description Alice and Bob wanted to exchange information secretly. The two of them agreed to use the Diffie-Hellman key exchange algorithm, using p = 13 and g = 5. They both chose numbers secretly where Alice chose 7 and Bob chose 3. Then, Alice sent Bob some encoded text (with both letters and digits) using the generated key as
morse-code Description Morse code is well known. Can you decrypt this? Download the file here. Wrap your answer with picoCTF{}, put underscores in place of pauses, and use all lowercase. Solving The soundfile is a morse code You could either translate it by your self with the morse alphabet or use this link Change all characters to lowercase and replace
credstuff Description We found a leak of a blackmarket website’s login credentials. Can you find the password of the user cultiris and successfully decrypt it? Download the leak here. The first user in usernames.txt corresponds to the first password in passwords.txt. The second user corresponds to the second password, and so on. Solving We got a tar file – extract
AAAAA AAAAA. That’s all Download AAAAA Okay – first of all, like always I run file on this AAAAA file. This will tell us, that this is a data file. After that, I tried binwalk. BÄM There is an image included. My colleague uses CyberChef for this. There you can import the file and run Extract files on. I just