Part. 2 - Old md5

Category: WEB - Points: 210 - Solves: Description: Decrypt the user's password. This step is the result of a three-part challenge. It is reset every 30min, so the platform may be unavailable for a few seconds. Link : https://web3.hackday.fr/

Solution: To solve this challenge you need to find a way to control the server and find the flag. The vulnerability was found in the Part. 1 - Uploads so we need to find the password of a special user. To find the special user, we need to analyze the passwd file. There is a (strange) user who can execute bash command : shrek Also, we can see that his home directory is /home/shrek so we decide to go at this directory. In this directory there is the fLaG2.txt file but we can't open it because we don't have permissions. Go back to home and we see that there is a file named important.txt. With a cat important.txt we receive an instruction to execute a program : So before execute him, we prefer to analyze his content by cat /.runme.sh : Oh ! We have the encrypted password for shrek : cf4c2232354952690368f1b3dfdfb24d With just 1 research on internet we find the md5 decrypted password => onion Now we can connect us by SSH with this command : ssh shrek@51.255.172.76 and this password : onion We go back to the home/shrek directory and analyze the fLaG2.txt file and we get the flag :

🚩 FLAG

  HACKDAY{ABVHDBRUshrekSKSDFMLOJFS654}