CMU Usable Privacy and Security Laboratory Phinding Phish: An Evaluation of Anti-Phishing Toolbars Yue Zhang, Serge Egelman, Lorrie Cranor, and Jason Hong

CMU Usable Privacy and Security Laboratory Anti-Phishing Tools 84 Listed on download.com (Sept. ‘06) Included in many browsers Poor usability Many users don’t see indicators Many choose to ignore them But usability is being addressed Are they accurate?

CMU Usable Privacy and Security Laboratory Tools Tested CallingID Cloudmark EarthLink

CMU Usable Privacy and Security Laboratory Tools Tested eBay Firefox

CMU Usable Privacy and Security Laboratory Tools Tested IE7

CMU Usable Privacy and Security Laboratory Tools Tested Netcraft Netscape

CMU Usable Privacy and Security Laboratory Tools Tested SpoofGuard TrustWatch

CMU Usable Privacy and Security Laboratory Source of Phish High volume of fresh phish Sites taken down after a day on average Fresh phish yield blacklist update information Can’t use toolbar blacklists We experimented with several sources APWG - high volume but many duplicates and legitimate URLs included Phishtank.org - lower volume but easier to extract phish Assorted other phish archives - often low volume or not fresh enough

CMU Usable Privacy and Security Laboratory Phishing Feeds Anti-Phishing Working Group ISPs, individuals, etc. >2,000 messages/day Filtering out URLs from messages PhishTank Submitted by public ~48 messages/day Manually verify URLs

CMU Usable Privacy and Security Laboratory Testbed for Anti-Phishing Toolbars Automated testing Aggregate performance statistics Key design issue: Different browsers Different toolbars Different indicator types Solution: Image analysis Compare screenshots with known states

CMU Usable Privacy and Security Laboratory Phish!! Warning!! Image-Based Comparisons Two examples: TrustWatch and Google TrustWatch: Google: ScreenShot Verified Not verified

CMU Usable Privacy and Security Laboratory Testbed System Architecture

CMU Usable Privacy and Security Laboratory Testbed System Architecture Retrieve Potential Phishing Sites

CMU Usable Privacy and Security Laboratory Testbed System Architecture Send URL to Workers

CMU Usable Privacy and Security Laboratory Testbed System Architecture Worker Evaluates Potential Phishing Site

CMU Usable Privacy and Security Laboratory Testbed System Architecture Task Manager Aggregates Results

CMU Usable Privacy and Security Laboratory Experiment Methodology Catch Rate: Given a set of phishing URLs, what percentage of them are correctly labeled as phish by the tool - count block and warning only - taken down sites removed False Positives: Given a set of legitimate URLs, what percentage of them are incorrectly labeled as phish by the tool - count block and warning only - taken down sites removed

CMU Usable Privacy and Security Laboratory Experiment 1 PhishTank feed used Equipment: 1 Notebook as Task Manager 2 Notebooks as Workers 10 Tools Examined: CloudMark Earthlink eBay IE7 Google/Firefox McAfee Netcraft Netscape SpoofGuard TrustWatch

CMU Usable Privacy and Security Laboratory Experiment phishing URLs PhishTank feed Manually verified Re-examined at 1, 2, 12, 24 hour intervals Examined blacklist update rate (except w/SpoofGuard) Examined take-down rate 514 legitimate URLs 416 from 3Sharp report 35 from bank log-in pages 35 from top pages by Alexa 30 random pages

CMU Usable Privacy and Security Laboratory Experiment 2 APWG phishing feed 9 of the same toolbars tested + CallingID Same testing environment

CMU Usable Privacy and Security Laboratory Results of Experiment 1

CMU Usable Privacy and Security Laboratory Results of Experiment 2

CMU Usable Privacy and Security Laboratory False Positives ToolbarFalse Positive SpoofGuard218 (42%) CallingID10 (2%) Cloudmark5 (1%) EarthLink5 (1%) Not a big problem for most of the toolbars

CMU Usable Privacy and Security Laboratory Overall findings No toolbar caught 100% Good performers: SpoofGuard (>90%)  Though 42% false positives IE7 (70%-80%) Netcraft (60%-80%) Firefox (50%-80%) Most performed poorly: Netscape (10%-30%) CallingID (20%-40%)

CMU Usable Privacy and Security Laboratory More findings Performance varied with feed Better with Phishtank:  Cloudmark, Earthlink, Firefox, Netcraft Better with APWG:  eBay, IE7, Netscape Almost the same:  Spoofguard, Trustwatch Different increases over time More increases on APWG Reflects the “freshness” of URLs

CMU Usable Privacy and Security Laboratory CDN Attack Many tools use blacklists Many examine IP addresses (location, etc.) Proxies distort URLs Used Coral CDN Append.nyud.net:8090 to URLs Uses PlanetLab Works on: Cloudmark Google TrustWatch Netcraft Netscape

CMU Usable Privacy and Security Laboratory Page Load Attack Some wait for page to be fully loaded SpoofGuard eBay Insert a web bug taking infinite load time 5 lines of PHP 1x1 GIF Infinite loop spitting out data very slowly Tool stays in previous state Unable to indicate anything

CMU Usable Privacy and Security Laboratory Conclusion Tool Performance No toolbars are perfect No single toolbar will outperform others Heuristics have false positives  Whitelists?  Hybrid approach? Testing Methodology Get fresher URLs Test other than default settings User interfaces Usability is important  Traffic light?  Pop up message?  Re-direct page?

CMU Usable Privacy and Security Laboratory