Infinity Shell Walkthrough

Challenge Statement#

Solution#

Since the challenge talks about a web application vulnerability, we can directly head to the website’s directory to look for suspicious files.

Going through all the files and folders, we see that there is an images.php file, which s PHP web shell.

The web shell allows us to execute commands on the server by passing them as a base64-encoded query parameter.
Now, we cannot do anything with this information, but we can look at the logs to see the attacker’s actions.

Command I used:

cat other_vhosts_access.log.1 | grep images.php?query=

From these, we can decode the base64 strings and obtain the flag.

Adapted from harishkannan05/THM-HackfinityBattle-Writeup under MIT.