1. All Your Contacts Are Belong to Us: Automated Identity Theft Attacks on Social Networks Reporter : 鄭志欣 Advisor: Hsing-Kuo Pao Date : 2010/12/06 1

2. Conference All your contacts are belong to us : automated identity theft attacks on social networks,Bilge, Leyla;Strufe, Thorsten;Balzarotti, Davide;Kirda, Engin, 18th International World Wide Web Conference, April 20-24, Madrid, Spain (WWW'09) 2

3. Outline  Introduction  iCloner overview  Cloning attacks  Evaluation  Suggestions for improvements in social network site security  Conclusion 3

4. Introduction (cont.)  Social network sites have been increasingly gaining popularity.  Business relationship  XING (5 million registered users,2008)  LinkedIn (80 million registered users,2010)  Friend relationship  Facebook ( 0.5 billion registered users,2010)  StudiVZ (16 million registered users,2010)  MeinVZ  As the Interest for a new technology grows on the Internet, miscreants are attracted as well.  E-mail  Social network (steal personal info.) 4

5. This paper do ….  This paper investigate how easy it would be for a potential attacker to launch this type of impersonation attacks in an automated fashion against a number of popular social networking sites in order to gain access to a large volume of personal user information. 5

6. iCloner  First Attack :  It clone an already existing profile in a social network and send friend requests to the contacts of the victim.  Second Attack :  It is effective and feasible to launch an automated, cross-site profile cloning attack. 6

7. Contributions  It is feasible in to launch automated attacks against five popular social networking sites.  Profile cloning, cross-site profile cloning.  There is significant room for improvement to make these CAPTCHAs more difficult to break.  That most social network users are not cautious when accepting friend requests or clicking on links that are sent to them.  It makes suggestions on how social networking sites can improve their security, and therefore, better protect the privacy of their users. 7

8. An architectural overview of iCloner 8

9. CAPTCHAs  CAPTCHA algorithm is the ability to generate tests that are at the same time easily solvable by humans, but very hard to solve for a computer application.  ImageMagick(Image filter) + Tesseract (OCR) 9

10. Breaking …..  MeinVZ and StudiVZ  Replace the background with white pixels  Isolate the letters (if overlapping,ask new CAPTCHA)  Scale all letters to same size  Tesseract  It can solve the CAPTCHA with 99.8% in one of the three consecutive attempts. 10

11. Breaking …  Facebook (reCAPTCHA)  Unbend the word back to the original shape  Translate pixel column up or down becomes a straight line  Similar to MeinVZ and StudiVZ steps  Compared with English dictionary,or submit the word to Google.  Success rate between 4% and 7%  Botnets and IPs 11

12. Cloning attacks  Profile cloning  Cross-site profile cloning 12

13. Profile cloning  Promise :  profile cloning attack is that social networking users are generally not cautious when accepting friend requests.  Many users will not get suspicious if a friend request comes from someone they know, even if this person is already on their contact list.  The profile cloning attack consists of identifying a victim and creating a new account with his real name and photograph inside the same social network.  Once the cloned account has been created, our system can automatically contact the friends of the victim and send friend requests.  Friend requests + Social engineering 13

14. Cross-site Profile Cloning  Aim :  Identify victims who are registered in one social network, but not in another.  Retrieve as much information as possible form victim original social network account.  Identify the friends of the victim in the original network and check which of them are registered in the target network. 14 FieldScore Education2 Company2 City & Country 1

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16. Evaluation  Crawling Experiments  Experiments (Profile Cloning)  Experiments(Cross-site profile cloning) 16

17. Crawling Experiments  StudiVZ and MeinVZ  40.000 profiles/day  5 million public user profiles with contact information and more than 1.2 million profiles with complete user information  Xing  118,000 profiles 17

18. Experiments (Profile Cloning)  1.Wanted to test how willing users would be to accept friendship requests from forged profiles of people who were already on their friendship lists.(in Facebook )  Using iCloner, it duplicated 5 user profiles (same name, arbitrary birth date, same picture, D1,…,D5)  iClone sent requests to all contact for each victim.( 705 users in total) 18

19. Experiments (Profile Cloning)  2.How effective profile cloning is with respect to requests that the contacted users might receive from people that they do not know  These profiles consisted of random names and pictures of arbitrary people.(F1,…,F5)  We contacted the same users from these accounts as with the respective forged profiles. 19

20. Experiments (Profile Cloning)  3How much trust users would have in messages that they would receive from their new contacts. 20

21. Experiments (Profile Cloning) 21

22. Experiments (Profile Cloning) 22

23. Experiments(Cross-site profile cloning)  A profile taken from a social network is cloned to another social network.  XING 30,000 profiles,and found 3,700 also registered in LinkedIn.(12%)  It clone 5 XING account into LinkedIn and iCloner identified 78 out of 443 XING (17.6%)friend contacts were also registered on LinkedIn  In 2008, XING have 5 million registers. This attack Upper bound to 600,000. 23

24. Experiments(Cross-site profile cloning) Of the 78 contact requests that we sent to the users in LinkedIn, 56%, in total 44, were accepted. 24

25. Suggestions for improvements in social network site security  Overlapping the CAPTCHAs symbol  Rate limit  behavior-based anomaly detection 25

26. Conclusion  How easy it would be for a potential attacker to launch automate crawling and identity theft attacks against five popular social network sites.  This paper present two identity automated theft attacks  Social networking sites are useful, we believe it is important to raise awareness among users about the privacy and security risks that are involved. 26