![Description](/auctf2020/img/description.png)
Clicking the link took me to the default apache page, so I decided to go straight into gobuster to find other pages.
![Gobuster](/auctf2020/img/gobuster.png)
First time I ran it the /cgi-bin/ directory stood out to me, so I ran it again on that directory and discovered the scriptlet file located within.
![Scriptlet](/auctf2020/img/whoami.png)
This appears to be a bash script that just runs whoami. Since this is bash, let's try exploiting shellshock. (cgi-bin + ctf - user input = shellshock)
To begin, I intercepted the request firefox was making to the script in burpsuite
![Burp1](/auctf2020/img/burp1.png)
And then hitting ctrl + R to send it to the repeater to make things eaiser.![Burp2](/auctf2020/img/burp2.png)
To test for shellshock, we can replace the user agent string with `() { :;}; echo; echo vulnerable` . If the response from the server contains the word `vulnerable`, we have a hit.
And it did.![Burp3](/auctf2020/img/burp3.png)
My home network wouldn't allow me to catch a reverse shell, but burpsuite is all the shell I need at this point. After some poking around, I found something interesting at / (full path for ls was required)
![Burp3](/auctf2020/img/binls.png)
catting the file revealed hex data![Burp3](/auctf2020/img/bincat.png)
So I threw that into cyberchef and decoded from hex. After decoding that cyberchef was nice enough to point out that this was gzipped data and just handed me the flag.![Burp3](/auctf2020/img/cyberchef.png)
Success! This was a really fun challenge.
