Challenge Name: The Fav Controversy
Category: Web
Target: http://140.245.25.63:8003/

1. Description

The challenge description mentions: “Every time you search for a ‘controversial’ topic, the site whisks you through a series of hidden doorways before showing you a blank result. The flag isn’t at the destination…it’s scattered across the journey itself.” It also hints at checking the browser history.

2. Analysis

Redirection Chain

When a “controversial” search term (like everything, truth, or admin) is entered into the search bar, the server initiates a chain of HTTP 302 redirects instead of directly serving the results.

By using curl -vL or monitoring the network history, the following redirect locations were observed:

  1. /next-page/id=Q1RGe3JjQ19rNF8=
  2. /next-page/id=ZCE1NV9MbUEwfQ==

These id parameters appeared to be Base64 encoded strings.

3. Solution

Step 1: Identify the Redirects

Sending a search request for a controversial term:

curl -v "http://140.245.25.63:8003/search?q=everything"

The first redirect points to: Location: /next-page/id=Q1RGe3JjQ19rNF8=

Following the first redirect:

curl -v "http://140.245.25.63:8003/next-page/id=Q1RGe3JjQ19rNF8="

The second redirect points to: Location: /next-page/id=ZCE1NV9MbUEwfQ==

Step 2: Decode the Segments

Decoding the Base64 strings found in the URLs:

  • Q1RGe3JjQ19rNF8= -> CTF{rcC_k4_
  • ZCE1NV9MbUEwfQ== -> d!55_LmA0}

Step 3: Assemble the Segments

Combining the segments results in the final flag.

4. Flag

CTF{rcC_k4_d!55_LmA0}