WEB TRANSPARENCY AT PRINCETON PRESENTER Christian Eubank PAPER

WEB TRANSPARENCY AT PRINCETON PRESENTER: Christian Eubank PAPER: Shining the Floodlights on Mobile Web Tracking [E. , Melara, Perez-Botero, Narayanan]

Original Motivation • Mobile tracking knowledge vacuum • Mobile devices are everywhere • Perceived measurement difficulty

Guiding Questions • How do companies track mobile devices differently? • What about tablets? • Physical v. emulated devices?

Our Approach • Data collection via Fourth. Party • FP Database Schema • Mixture of manual/automated analysis

Mobile Java. Script crawler • Originally considered: • Future: desktop crawls with Selenium

Findings: Few Mobile-Only Networks • • • Otherwise, . mobile and m. addresses

Findings: Devices Roughly Similar Desktop Asus Galaxy Phone E. Tab E. Phone 1. 00 0. 77 0. 82 0. 76 0. 75 1. 00 0. 87 0. 83 0. 84 0. 83 Galaxy 1. 00 0. 88 0. 87 Phone 1. 00 0. 86 0. 95 E. Tab 1. 00 0. 86 E. Phone 1. 00

Cookie Expiration Time (days) Findings: Cookie Longevity 7 6 5 4 First Party 3 Third Party 2 1 0 Desktop Asus Galaxy Phone E. Tab E. Phone Device

Growing Cookies: yieldmanager’s bh Cookie Value String Domain EXAMPLE 1 "b!!!!#!!2 -]!!!!#>+YEL" Netflix "b!!!!$!!2 -]!!!!#>+YEL!%HWu!!!!#>+YE]" Cracked "b!!!!%!!2 -]!!!!#>+YEL!%HWu!!!!#>+YE]!%ODP!!!!#>+YF$" Salon EXAMPLE 2 "b!!!!#!%HWu!!!!#>+YG<" Cracked "b!!!!$!%HWu!!!!#>+YG<!%ODP!!!!#>+YGC" Salon "b!!!!%!!2 -]!!!!#>+YGP!%HWu!!!!#>+YG<!%ODP!!!!#>+YGC" Netflix EXAMPLE 3 "b!!!!#!%ODP!!!!#>+YLs" Salon "b!!!!$!!2 -]!!!!#>+YM$!%ODP!!!!#>+YLs" Netflix "b!!!!%!!2 -]!!!!#>+YM$!%HWu!!!!#>+YM, !%ODP!!!!#>+YLs" Cracked Bold text indicates site ID; Underlined text indicates user ID Hwu = cracked. com; 2 -] = netflix. com; ODP = salon. com

Growing Cookies: Takeaways • Third parties storing on client • Placed by 8% of desktop third parties • Possible growing cookie library

Next Steps • Continued Cookie Analysis • Deeper Crawls • Exploring rich data from Fourth. Party • Our data open to other researchers

Automated Framework WWW Controller DATA

Overarching Goals • Keep public informed • Help to shape policy • Promote web transparency • Individual case studies under umbrella of web transparency

Leveraging our infrastructure • Automatic social media interaction • Detecting cookie synchronization

Conclusion • Need for web transparency • Currently building measurement tool • We invite collaboration

QUESTIONS?