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PORTIA Project

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.

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Sample phishing email

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Sample phishing sitehttp://202.69.39.30/snkee/....

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Magnitude of problem

Fastest growing crime on the Internet.

Trends: keyloggers from phishing sites.

http://www.antiphishing.org

2004-5 Mar Feb Jan … July Jan

spoofs/ month

2870 2686 2602 … 1634 113

# targets 78 68 64 … 13 7

March, 05:

80% at 8 brands, average uptime 5.8 days, 81% of targets are financial

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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).

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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.

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PORTIA Project

1. SpoofGuard:Detect Phishing Web Sites

http://crypto.stanford.edu/SpoofGuard

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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.

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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.

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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

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PORTIA Project

2. PwdHash: Improved Pwd Mgmt

http://crypto.stanford.edu/PwdHash

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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:

1. Locate all pwd HTML elements on page:

2. When form is submitted replace all pwd’s by:PRFpwd(domain-name)

3. Phishing site only sees hash of Ebay password.

The challenge: Extremely hard to implement securelyin a modern browser!

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PwdHash Challenges

1. Javascript attacks2. Pwd reset after plug-in install

3. Dictionary attacks (sol: EKE or SFE for equality test)

4. What salt to use in hash?

5. How to encode resulting hash?

6. Internet Café

Our design goal: transparent to user.

Impact: 1. Google: PhD intern.2. TIPPI working group: MS, Mozilla,

RSA

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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

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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.

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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 modernbrowser.

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PORTIA Project

SpyBlock

Spyware defense tool

Current work

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SpyBlock design

Proxy VM keeps sensitive user info away from SpyWare.

User hits pwdkey before and after typing sensitive info.

VMWare ACE Server / Xen

Guest OS

Firefox Proxy VM

SpyW

are

apps

https page

PwdKey

KeysJunk

https

junkdata

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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.