FirstBlood-#234Event is leaking attendees Personal information.

On 2021-05-14, th4nu0x0 reported:


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:

  1. Visit you'll just encounter 200 OK with nothing in response.
  2. Now visit the same URL and intercept the request and add this header to the request x-site-req: permitted

Without Header:

With Header:


Disclosure of PII of Event attendees.


Endpoint: /attendees/event.php?

Parameter: q

Payload: x-site-req: permitted

FirstBlood ID: 13
Vulnerability Type: Info leak

/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.

Respect Earnt: 1500000
RESPECT ($RSP) is an experimental cryptocurrency based on the Ethereum blockchain with the mission to show respect to those who deserve it. We are testing it out on our FirstBlood hackevent.