The Battle Against Phishing: Dynamic Security Skins

1. The Battle Against Phishing:Dynamic Security Skins Rachna Dhamija and J.D. Tygar U.C. Berkeley

2. Security Properties for Usability • Limited human skills property • Unmotivated users property • General purpose graphics property • Golden arches property • Barn door property

3. Security Properties for Usability • Limited human skills property • Unmotivated users property • General purpose graphics property • Golden arches property • Barn door property

4. Limited Human Skills Property • Limited password recall • Hard to parse domain names

5. Security Properties for Usability • Limited human skills property • Unmotivated users property • Security is often the secondary goal • General purpose graphics property • Golden arches property • Barn door property

6. Users Don’t Check Certificates

7. Security Properties for Usability • Limited human skills property • Unmotivated users property • General purpose graphics property • Golden arches property • Barn door property

8. Firefox Browser: 4 SSL indicators

9. Firefox browser - No unsecure indicators

10. Security Properties for Usability • Limited human skills property • Unmotivated users property • General purpose graphics property • Golden arches property • Train users not to automatically trust a logo or brand • Barn door property

11. The golden arches property

12. Security Properties for Usability • Limited human skills property • Unmotivated users property • General purpose graphics property • Golden arches property • Barn door property

13. Strong Password Protocols • Stanford Web PwdHash • Password Authenticated Key Agreement • EKE, SPEKE, SNAPI, AuthA, PAK, SRP, etc… • Password • H(password, siteID) • Protocol • Password

14. Password Authenticated Key Agreement • Advantages: • preserve familiar use of passwords • user doesn’t need a trusted device • secret stored in memory of the user • server doesn’t store password • no passwords sent over the network • user authentication (& mutual authentication) • But how to enter the password?

15. Our Solution: Usability Goals • User must be able to verify password prompt, before entering password • Rely on human skills • To login, recognize 1 image & recall 1 password • To verify server, compare 2 images • Hard to spoof security indicators

16. Trusted Password Window • Dedicated window • Trusted path  customization • Random photo assigned or chosen • Image stored in browser, do not have to go through server • Image overlaid across window • User recognizes image first • then enters password • Password not sent to server

17. Security Indicators • How can user distinguish secure windows? • Static indicators (SSL) • Can be spoofed • User do not really examine it • User customized indicators (Passmark/Petnames) • Require extra efforts from the user • Automated customized indicators

18. Our Solution: Dynamic Security Skins • Automatically customize secure windows • Visual hashes • Random Art - visual hash algorithm • Generate unique abstract image for each authentication • Use the image to “skin” windows or web content • Browser generated or server generated

19. Browser Generated Images • Browser chooses random number and generates image • Can be used to modify border or web elements

20. Server Generated Images • Server & browser independently generate same image • Server can customize its own page

21. Conclusions • Benefits: • Achieves mutual authentication • Resistant to phishing and spoofing • Relies on human skills • Weaknesses: • Users must check images • easier than checking a cert • Local storage of personal image reduces portability, requires security • Doesn’t address spyware, keyloggers

22. Status and Future Work • Iterative design & “lo-fi” testing of interface • Formal user study • DSS Mozilla extension

24. Customized Indicators: Petname Toolbar

25. Automated Indicators:Secure Random Dynamic Boundaries