HackIM2017 CTF -Web Challenges and solutions (part-3)

Solving Web300 Challenge


There was sudden absence of a hint here! OK!.., so viewed view source. Nothing. Hmm! had an Ominous feeling starting this one ..


Accessed the web page and it appeared to be a command line injection attack. Trying couple of variations with  http:// /? c m d = ls  and no output!. This appears to be blind injection and the tool that can be used to test this kind of vulnerability is commix. I used the default utility in Kali 2.0 and it kept running into “Error Near Syntax” and it either stopped working there or succeeded and  failed to give me a complete result within the “os_shell” prompt. “reverse_tcp” was always another option, but i felt “os_shell” had to work for either to function.


I located the git hub page and cloned it. This version worked quite well, but again hit issues with some other area.  I was not able to retrieve the sets of chars consistently for the flags. Kept getting chars between 4 to 6 and junk data. On inspecting further, noticed there are packet drops on my ISP.


Finally after my ISP issues were sorted, i tried again and got the flags!. web3005


This was indeed a nice flag. Learn’t so much about time based command injection and automation tool to test this effectively. The techniques used by Commix specifically -time-based and file-based are really great to research more on.


Published by Ramnath Shenoy

I work a penetration tester and this blog is just some of my personal notes!

Leave a comment

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: