Presentation By :- Krishna Sai Mulpuri An Empirical Evaluation of Security Indicators in Mobile Web Browsers Chaitrali Amrutkar, Patrick Traynow and Paul C. van Oorschot Presentation By :- Krishna Sai Mulpuri

CONTENT Section 1 Introduction Section 2 Terminologies and Guidelines Observations of Results Section 4 Additional Results Section 5 User’s interaction and Possible attacks Section 6 Conclusion

Introduction Mobile platform is very popular in the 21st century, it provides a rich set of features that often rival their desktop counterparts. Mobile platform in combination of strong cryptographic tools including SSL/TLS, allows users to become increasingly reliant upon mobile devices to enable sensitive personal, social and financial exchanges. A 2011 report indicates that mobile users are three times more likely to access phishing websites than desktop users. W3C has set forth some guidelines to convey security for web user interface. Some experiments are performed on browsers of both mobile and desktop.

W3C TERMINOLOGIES User Interface Elements Trust Anchor Root Trusted Root Certificates Pinning Identity Signal Strong TLS Weak TLS Error Messages

W3C GUIDELINES Identity Signal : Availability Certificates : Required Content TLS Indicators Significance of presence Content & Indicator Proximity Availability & Robustness Robustness : Visibility of Indicators Error Messages Interruption Proceeding Options Inhibit Interaction

AUTHORS TEST SETUP

IDENTITY SIGNAL Contains information about website owner and corresponding certificate issuer information

CERTIFICATES MUST provide reasons of TRUST Domain Name Reason of Trust accepted interactively or not self-signed or not presented to user or not

CERTIFICATES

TLS INDICATORS Availability Robustness Significance of Presence Content & Indicator Proximity Availability Robustness

TLS INDICATORS

SOME OBSERVATIONS OF TLS INDICATORS

ROBUSTNESS Web content MUST NOT obscure the security user interface. Some TLS indicators on UI are lock icon, site identity button, https URL prefix. visibility is dependent on screen and its properties.

ERROR MESSAGES Interruption Proceeding Options Inhibit Operation

SOME OBSERVATIONS OF ERROR MESSAGES

ADDITIONAL RESULTS(+ve) SSL version 2 MUST NOT hold strong and after the experiment authors found that None of the browsers in either mobile or tablet support it. The NULL Cipher is one of the most dangerous ciphers as it represents lack of an encrypted communication channel. Authors found that None of the browsers either in mobile or tablet support the null cipher.

ADDITIONAL RESULTS(-ve) Browser supporting weak cipher can enable a network attacker to break the encrypted messages . Authors perform check on DES-CBC-SHA weak cipher. Observations 6 mobile & tablet browsers support weak cipher. Others display error messages conveying absence of encryption protocol with server.

Phishing using compromised CA POSSIBLE ATTACKS Four types of are discussed which are possible due to violation of one or more W3C Guidelines. attacks If W3C Guidelines are not followed then users can be easily misled about the identity of the website or the security of the connection. Phishing without SSL Phishing with SSL Phishing using compromised CA Industrial Espionage

PHISHING WITHOUT SSL Attacker masquerades as a trustworthy entity in the attack as closely imitates the legitimate website’s identity along with lock icon spoofing, launching attack without SSL on browser. Domain name quite similar to legitimate website which provides an impression of correct identity of website. Makes the favicon a lock image which provides an illusion for strong encryption. When rendered in a browser where URL viewing is difficult or doesn’t offer a UI to view identity information of website, then even advance user might get subjected to phishing.

PHISHING WITH SSL Spoofing only lock icon is not adequate for a successful phishing attack. An attacker can buy an inexpensive SSL Certificate for website to increase credibility of attack.

PHISHING USING COMPROMISED CA Attacker obtains rogue certificates for legitimate websites by compromising CA. If a browser trusts a CA then it doesn’t checks if CA is compromised or not. An expert user can verify certificate issuer’s organization in the chain, thus not interacting with malicious website having a rogue certificate. But if browser doesn’t allow user interface to have certificate viewing, then even an expert user can be subjected to phishing attack. PHISHING USING COMPROMISED CA

CONCLUSION Modern mobile browsers enable a wide range of sensitive operations over SSL/TLS connections. They lack behind when compared with desktops, due to the small scree size. small screen size of mobile browsers causes lot of inconsistencies in the presentation of SSL indicators. Addition of EV-SSL certificates make the mobile ecosystem more complex without producing much benefits. Even for expert users, detecting security issues is not easy, which makes the life of average users much harder.

Questions?

THANK YOU