Lab: Username enumeration via different responses
This lab is vulnerable to username enumeration and password brute-force attacks. It has an account with a predictable username and password, which can be found in the following wordlists:
To solve the lab, enumerate a valid username, brute-force this user's password, then access their "My account" page.
- With Burp running, investigate the login page and submit an invalid username and password.
In Burp, go to "Proxy" > "HTTP history" and find the
POST /loginrequest. Send this to Burp Intruder.
- In Burp Intruder, go to the "Positions" tab. Make sure that the attack type "Sniper" is selected.
Click "Clear" to remove any automatically assigned payload positions. In the
usernameparameter, highlight the value and click "Add" to add a payload position to this parameter. This position will be indicated by two
§symbols, for example:
- Leave the password as any static value for now.
- On the "Payloads" tab, select payload type "Simple list".
- Under "Payload options", paste the list of candidate usernames and click "Start attack". The attack will start in a new window.
- When the attack is finished, on the "Results" tab, examine the "Length" column. Click on the column header to sort the results. Notice that one of the entries is different to the other ones.
Examine this response. Notice that other responses contain the message
Invalid username, but this response says
Incorrect password. Take note of this username.
Close the attack and go back to the "Positions" tab. Click "Clear" again and change the
usernameparameter to the username you just identified. Add a payload position to the
- On the "Payloads" tab, clear the list of usernames and replace it with the list of candidate passwords. Then click "Start attack".
- When the attack is finished, look at the "Status" column. Notice that each request returned a 200 status code, until eventually one returns 302. This suggests that the login attempt was successful. Take note of the password.
- Back in your browser, log in using the username and password that you identified.
- Click "My account" to solve the lab.