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Mitigating Online ID Theft: Phishing and Spyware

Students : Blake Ross, Collin Jackson , Nick Miyake, Yuka Teraguchi, Robert Ladesma, Andrew Morrison Faculty : Dan Boneh and John Mitchell Special thanks to the SF-ECTF and SS . Mitigating Online ID Theft: Phishing and Spyware. Sample phishing email. http://202.69.39.30/snkee/.

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Mitigating Online ID Theft: Phishing and Spyware

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  1. Students: Blake Ross, Collin Jackson, Nick Miyake, Yuka Teraguchi, Robert Ladesma, Andrew Morrison Faculty: Dan Boneh and John Mitchell Special thanks to the SF-ECTF and SS. Mitigating Online ID Theft: Phishing and Spyware

  2. Sample phishing email

  3. http://202.69.39.30/snkee/.... Sample phishing site

  4. Magnitude of problem • Fastest growing crime on the Internet. • Trends: keyloggers from phishing sites. http://www.antiphishing.org

  5. What can we do about phishing? • Spam filter: • Phishing starts with email, so stop it there. • Non-trivial: phishing emails look like ordinary email. • Client-side methods: • Anti-phishing using browser plug-ins. • Anti-spyware using Virtual Machine Monitors. • Server-side methods: • Personalized web pages. • Improved user authentication (e.g. tokens or certs).

  6. PORTIA ID Protection Work • Long term effort to develop online ID protection tools. • SpoofGuard:(NDSS ’04) • Alerts user when browser is viewing a spoofed web page. • Uses variety of heuristics to identify spoof pages. • A new type of anomaly detection problem. • PwdHash: (Usenix Sec ’05) • Simple mechanism for strengthening password web auth. • SpyBlock: (under development) • A Virtual Machine (VM) approach to SpyWare defense.

  7. 1. SpoofGuard:Detect Phishing Web Sites http://crypto.stanford.edu/SpoofGuard

  8. SpoofGuard Browser Plug-in • Compute spoof index: • Weighted sum of several spoof measures • Depends on current page and browsing history • Provides two forms of information: • Passive alerts in toolbar. • Active blocking when necessary. • Challenges: • Must be easy for novice users. • Detect malicious pages yet minimize false alarms.

  9. Sample Heuristics • History Check: • Site is assumed OK if in user’s history list. • Domain Check: • Check similarity to domain in history list. • Email Check: • Suspicious if page is reached by following email link • Impact: • Ebay toolbar, Yahoo! toolbar, WholeSecure • Multiple requests for Firefox support.

  10. Current/future work • SpamAssassin extensions: • Download pages that URL’s in incoming email point to. • Run SpoofGuard heuristics on downloaded pages. • Spam archive scanning: • Automatic detection of new phishing sites. • www.spamarchive.org

  11. 2. PwdHash: Improved Pwd Mgmt http://crypto.stanford.edu/PwdHash

  12. Strengthen Web Pwd Auth • Current web auth: cleartext password over SSL • Vulnerable to phishing. • Vulnerable to break-ins at low security sites. • Simple improvement: Browser plug-in that converts a user’s pwd into a unique pwd per site: • Locate all pwd HTML elements on page: • When form is submitted replace all pwd’s by:PRFpwd(domain-name) • Phishing site only sees hash of Ebay password. • The challenge: Extremely hard to implement securelyin a modern browser!

  13. PwdHash Challenges • Javascript attacks • Pwd reset after plug-in install • Dictionary attacks (sol: EKE or SFE for equality test) • What salt to use in hash? • How to encode resulting hash? • Internet Café • Our design goal: transparent to user. • Impact: 1. Google: PhD intern. 2. TIPPI working group: MS, Mozilla, RSA

  14. Javascript attacks • Phishing site can create Javascript to steal user’s unhashed password. • Record all key-strokes sent to page • Change target-domain-name on submit • Mask regular text field as a password field

  15. Javascript attacks (cont.) • Defense 1: Password prefix / Password key • Ask user to start all passwords with “@@” • Plus-in traps all keyboard events to window. • When “@@” detected, replace subseq. keys with ‘%’ • Browser never sees pwd. • On ‘BeforeNavigate2’ event, replace ‘%%%’ in POST data with hashed pwd. • Alert user if “@@” detected in key stream while focus not on pwd field.

  16. Pwd Salting – an old idea • Hash pwd with realm provided by remote site: • HTTP 1.1 Digest Authentication • Kerberos 5 • Hash pwd with network service name: • Gabber, Gibbons, Mattias, Mayer [FC ’97]. Proxy. • Abadi, Bharat, Marais [PTO ’97] • Challenge: implementing securely in a modern browser.

  17. Spyware defense tool Current work SpyBlock

  18. https page https junkdata Junk Keys PwdKey SpyBlock design • Proxy VM keeps sensitive user info away from SpyWare. • User hits pwdkey before and after typing sensitive info. Proxy VM Firefox SpyWare apps Guest OS VMWare ACE Server / Xen

  19. Summary • Long term effort focused on ID protection tools. • Current tools: SpoofGuard, PwdHash, Current/future work: SpyBlock • Strong focus on technology transfer: • Interns help do tech transfer. • Source code available on PORTIA web site. • Close collaboration with SF-ECTF.

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