Facebook flaw allows the disclosure of Friends List

This POC demonstrates that exploiting a Facebook flaw it is possible the disclosure of Friends List EVEN WHEN HE HAS BLOCKED ACCESS TO VIEW IT

This is a Proof of Concept made by BHAVESH NAIK

DO YOU WISH TO SEE WHO IS IN YOUR FRIENDS LIST, EVEN WHEN YOUR FRIEND HAS BLOCKED ACCESS TO VIEW HIS FRIENDS LIST?

IF YOUR ANSWER IS ‘YES’, THEN READ THE FOLLOWING PROCEDURE TO VIEW YOUR FRIENDS INACCESSIBLE FRIENDS LIST ON FACEBOOK.

It was JULY 17, 2013 when I discovered this little loophole and I submitted the vulnerability to Facebook but then I wasn’t in the ‘Hall of Fame’ and neither did I receive any sort of acknowledgement or recognition.

Well without wasting much time, I will start with the PoC.

Note : Prior to this you should know your friends email address.

The following screenshot is the victims (your friend) privacy setting , it shows that nobody is allowed to see the friends list:

Now the attack, visit http://facebook.com and select “Forgot your password?”

There you will be prompted to enter the email address. Enter the victims email ID:

You will see the following page:

You will be prompted to enter a new email address. Enter any email ID not associated to facebook.

Press ‘Continue’. You will be asked as to how you want to recover your account.

Click on ‘Recover your account with help from friends’

VOILA ! You see the friends list

I was wondering, “What is the use of such privacy setting when it can be bypassed by abuse of other functionality?”.

Status: Unfixed.

Reported: Yes

BHAVESH NAIK

Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.