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Blackout Profile
Blackout Profile
Author: Advika
This is a crypto+web-based CTF challenge demonstrating an Insecure Direct Object Reference (IDOR) vulnerability.
Firstly for the Crypto part:
We can use common online tools like Cyberchef to solve the following 3 challenges.
The challenges are basic base64 encoding, caeser cipher (bruteforce), simple xor with the given key.
For the IDOR part: First, we access the login page
The application provides a login form. Use the credentials provided with the previous challenge:
Username: Alice Password: very_secure_pwd
After logging in, the application redirects to:
/idor/profile/1001
Since the profile ID is directly exposed in the URL, we test whether changing it allows access to another user’s profile.
We change the profile value 1001 to 1
The application returns another employee profile, confirming that it does not properly verify whether the authenticated user is authorized to access the requested profile.
The vulnerability is an Insecure Direct Object Reference (IDOR). The application exposes an internal object identifier directly in the URL:
/idor/profile/
The server accepts an arbitrary user_id and retrieves the corresponding profile without checking whether the current user is authorized to access it.
Flag
CYS{idor_is_just_an_object_reference}