Event is leaking attendees Personal information.

FirstBlood-#234 — Event is leaking attendees Personal information.
This issue was discovered on FirstBlood v1

This report has been reviewed and accepted as a valid vulnerability on FirstBlood!

On 2021-05-14, th4nu0x0 Level 2 reported:


        Summary:
On /hackerback.html there's a endpoint mentioned on the page source /attendees/event.php?q=560720 which seems to do nothing when we just visit the endpoint normally but by adding the header x-site-req: permitted the endpoint reveals the PII of the attendees like email, name, contact number and last 4 digit of CC.
Steps To Reproduce:

Visit http://firstbloodhackers.com/attendees/event.php?q=560700 you'll just encounter 200 OK with nothing in response.
Now visit the same URL and intercept the request and add this header to the request x-site-req: permitted

Without Header:

With Header:

Impact:
Disclosure of PII of Event attendees.

This report has been publicly disclosed for everyone to view

P1 CRITICAL

Endpoint: /attendees/event.php?

Parameter: q

Payload: x-site-req: permitted

FirstBlood ID: 13
Vulnerability Type: Information leak/disclosure

/attendees/event can be seen on the HackerBack.html page but has a blank response. Upon further inspection and from making use of the web app, you will notice you can add certain headers in order to interact with this endpoint. An old event ID leaks PII information about attendees.

BugBountyHunter

Summary:

Steps To Reproduce:

Without Header:

With Header:

Impact: