NotFooter

Description

Wonder how http knows what browser i am using...

url

Solution

• From the description, we can conclude that it is referring to the User-Agent header

• We can see that it is expecting ctfbrowser as the User-Agent. This can be done in 2 ways:

  1. Intercept request using BurpSuite and change the User-Agent header

  2. Using curl

Using BurpSuite

• Intercept the request using BurpSuite and change the User-Agent header to ctfbrowser

burp1

• Forward the request and we get the flag

flag

Using curl

• We can use curl to send a request with a custom User-Agent header

$ curl -A "ctfbrowser" https://isfcr-notfooter.chals.io/                                   
pesu_ec{h34d3r5_4r3_us3ful}
<title>Special agent</title> 

-A: To set the User-Agent header

FLAG:

pesu_ec{h34d3r5_4r3_us3ful}