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This research proposes a scheme to prevent users from posting confidential data to spoofed websites, defending against phishing attacks. The scheme involves predicting user-expected identity and distinguishing spoofed sites from trusted ones. Experimental results show promising outcomes.
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Anti-Phishing Scheme: Preventing Confidential Data from Posted to Spoofed Site 2006.02.20 Researcher: Hunsuk Choi Presenter: Yuna Kim High Performance Computing Laboratory, POSTECH, Republic of KOREA
Contents • Phishing Attack • Problem Definition • Proposed Scheme • Experiments • Conclusion & Future Works
Introduction • Phishing is a form of social engineering trying to fraudulently acquire confidential information by masquerading as a trustworthy business. • Phishing attacks are becoming more popular because unsuspecting people are divulging personal information to attackers. • So, anti-phishing schemes are required neither to trust nor to qualify users.
1. Register ID = aaaPASSWORD = bbb Phishing Attack Model This is Trusted Site T User-expected identity = T Public trust site T 2. Target 4. Send Mail Target site of phisher P = T Please verify your account User A’s Computer User A Phisher P Victim of phiser P 3. Build 5. Post Spoofed site X of T ID = aaaPASSWORD = bbb
Related Works • Fraud e-mail prevention • (-) easily evaded by the sophisticated phishers. • Browser-based Web-spoofing prevention • (-) web site is easily spoofed by drawing logos. • (-) most users have no knowledge of certificate authorities. • Authenticator prevention • (-) disable to defend against man-in-the-middle attack. • (-) not scalable.
Problem Definition • To prevent a user from posting his confidential information to a spoofed website, while the user does not have explicit knowledge about details of the function of the Web service. Design Requirements • Systematic decision • Infrequent user work • Infrequent interruption
Basic Idea Prevent a user from posting confidential data to a spoofed website. • Determine whether the posted data is confidential data or not. • Distinguish spoofed site from trusted site. • Predict a user-expected identity of the current site based on data typed by user. • Compare a user-expected identity with the real identity of the current site.
Phase 1: Initialization • User registers the domain of trusted sites into the client system as the following record: • Type 1 record : <identity, domain, level> Phase 2: Training • When the user posts data to the trusted sites, the client system stores data as the following record: • To prevent type 2 records from increasing up to a great volume, delete older and smaller-counter records. • Type 2 record: <URL, field_name, H(v), counter, timestamp>
Phase 3: Prediction • When a user posts data to non-trusted site, the client system predicts the user-expected identity. • The user-expected identity infers one of the trusted site whose stored field value is same as the current posted data. Phase 4: Collaboration • If user-expected identity and real-identity are different, • the current site may be a spoofed site or a sister-site of the trusted site. • In order to distinguish them, the client agent queries to the server-agent whether the current site can be authenticated.
Phase 5: Prevention • The client system judges the current site is a spoofed if • Current site is not registered as a trusted site. • None of server agents can authenticate the current site. → User posts the same confidential data as one of the trusted sites, but current site is not sister-site. • The client system rejects the posting user tries, and registers in black list, which the site is spoofed one.
trusted site T1Domain = D1 Spoofed site X of T1 Applied Scenario Server agent of T1 This is Trusted Site T1 8. Query Is X sister-site ? 9. No 3. Store <U1, P/W, 35, 1, 10:00> 1. Register 4. Post <T1, D1, limited> ID = aaaP/W = bbb 2. Fill out User User’s com ID = aaaP/W = bbb 5. Connect the spoofed site X 10. Prevent 7. Predict 6. Fill out User-expected identity = T1 ID = aaaP/W = bbb
Counts Accumulated # of Transactions Experiment • No phishing attack • Interruptions • 2 times • # of type 2 records • stayed in a steady state in spite of internet searching • We want to show that type 2 records are not increasing up to a great volume. • Real world data of 2 users for 5 days # of Type 2 records # of confidential information → We can apply this scheme to real web browser. accumulated # of interruptions
Conclusion & Future Works • We proposed a mechanism that defends against phishing attacks by preventing a user from posting data to a probably spoofed website. • We expect that a proper human-computer interaction which helps a system understands the meaning of a user’s activity will provide a useful defense against not only phishing attacks but also other kinds of attacks targeting users. • As a future work, we are required to implement the proposed mechanism.
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