Lab: Exploiting NoSQL injection to extract data

The password only uses lowercase letters.

1. In Burp's browser, access the lab and log in to the application using the credentials wiener:peter.

2. In Burp, go to Proxy > HTTP history. Right-click the GET /user/lookup?user=wiener request and select Send to Repeater.

3. In Repeater, submit a ' character in the user parameter. Notice that this causes an error. This may indicate that the user input was not filtered or sanitized correctly.

4. Submit a valid JavaScript payload in the user parameter. For example, you could use wiener'+'

   Make sure to URL-encode the payload by highlighting it and using the hotkey Ctrl-U. Notice that it retrieves the account details for the wiener user, which indicates that a form of server-side injection may be occurring.

5. Identify whether you can inject boolean conditions to change the response:

   1. Submit a false condition in the user parameter. For example: wiener' && '1'=='2

      Make sure to URL-encode the payload. Notice that it retrieves the message Could not find user.

   2. Submit a true condition in the user parameter. For example: wiener' && '1'=='1

      Make sure to URL-encode the payload. Notice that it no longer causes an error. Instead, it retrieves the account details for the wiener user. This demonstrates that you can trigger different responses for true and false conditions.

6. Identify the password length:

   1. Change the user parameter to administrator' && this.password.length < 30 || 'a'=='b, then send the request.

      Make sure to URL-encode the payload. Notice that the response retrieves the account details for the administrator user. This indicates that the condition is true because the password is less than 30 characters.

   2. Reduce the password length in the payload, then resend the request.
   3. Continue to try different lengths.
   4. Notice that when you submit the value 9, you retrieve the account details for the administrator user, but when you submit the value 8, you receive an error message because the condition is false. This indicates that the password is 8 characters long.

7. Right-click the request and select Send to Intruder.

8. In Intruder, enumerate the password:

   1. Change the user parameter to administrator' && this.password[§0§]=='§a§. This includes two payload positions. Make sure to URL-encode the payload.
   2. Set the attack type to Cluster bomb.
   3. In the Payloads tab, make sure that Payload set 1 is selected, then add numbers from 0 to 7 for each character of the password.
   4. Select Payload set 2, then add lowercase letters from a to z. If you're using Burp Suite Professional, you can use the built-in a-z list.
   5. Click Start attack.
   6. Sort the attack results by Payload 1, then Length. Notice that one request for each character position (0 to 7) has evaluated to true and retrieved the details for the administrator user. Note the letters from the Payload 2 column down.

9. In Burp's browser, log in as the administrator user using the enumerated password. The lab is solved.

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