A Crawler-based Study of Spyware on the Web Author: Alexander Moshchuk, Tanya Bragin, Steven D.Gribble, Henry M.Levy Presented At: NDSS, 2006 Prepared By: Amit Shrivastava

Overview User visits website Web spyware infects computer Computer is unhappy vs.

Introduction Spyware study Infected 80% of AOL users 93 spyware components (known) Goals Locate spyware on the internet Gather Internet spyware statistics Quantitative analysis of spyware-laden content on the web

Introduction cont. What is spyware? Crawling the web Web executables Drive-by downloads Results Improvements

Definition Spyware – software that collects personal information about users No user knowledge Spyware techniques: Log keystrokes Collect web history Scan documents on hard disk

Types of Spyware Spyware-infected executables Content-type header URL extension Drive-by downloads Malicious web content Produce event triggers

Executable files Finding executables Content-type (HTTP header) contains.exe URL contains.exe,.cab, or.msi Hidden executables Embedded file (.zip) URL hidden in JavaScript Missed executables Hidden URL on dynamic page

Executable files DL, install, run in a clean VM Tool to automate installer framework EULA agreements Radio buttons and check boxes Analyze file Ad-Aware software Log identifies spyware program

Web Crawling Heritrix public domain Web crawler Search 2,500+ web sites Different categories 1) Celebrity sites 2) Games sites 3) Music sites 4) Adult sites 5) Online news sites 6) Wallpaper sites 7) Pirate sites

Changing Spyware Environment 2 separate program crawls May, October 2005 Most recent anti-spyware program used October crawl detect mores vulnerabilities

Executable Results 2 separate program crawls May 2005 – 18 million URLs Oct 2005 – 22 million URLs No appreciable change in spyware

Infected Executables   MAY 2005

Infected Executables October 2005

Web Categories Web categories infected with spyware

Spyware Functions Spyware-infected executables Contain various spyware functions Executables may have multiple functions

Spyware Upgrades Spyware-infected executables May have multiple spyware functions 1,294 infected.exe found in Oct detected 414 new one

Blacklisting Spyware Block clients from accessing listed sites Done by firewall or proxy Blacklisting is ineffective

Drive-by Downloads Spyware from visiting a web page Javascript embedded in HTML Modifies system files Modifies registry entries.

Event Triggers Event occurs that matches a trigger Trigger Conditions Process creation File activity (creation) Suspicious process (file modification) Registry file modified Browser/OS crash

IE Browser Configuration Security-related IE dialog boxes

Drive-by Results 3 web crawls May 2005 – 45,000 URLs Oct 2005 – Same URLs Oct 2005 – New URLs Decrease in infectious URLs Increase in unique spyware programs

Origin of Drive-by DLs Top 6 web categories (IE): Pirate sites Celebrity Music Adult Games Wallpaper

Spyware Top 10 Top 6 web categories (IE): Pirate sites Celebrity Music Adult Games Wallpaper MAY 2005 OCTOBER 2005

Spyware Top 10 May 2005October 2005

Spyware Trends Decline in total # of spyware programs Increase of anti-spyware tools Automated patch installations Lawsuits against spyware distributors

Firefox Security

Strengths Analysis method Studies density of spyware on the Web Produces spyware trends over time Calculated frequency of spyware on web Distinguished security prompts (y/n) Found 14% of spyware is malicious Density of spyware is substantial

Weaknesses  URL hidden in JavaScript, dynamic page  Limited by what Ad-Aware is able to detect  Different anti-spyware programs (May/Oct)  Did not crawl entire web

Improvements Test multiple browsers Additional anti-spyware programs Crawl more URLs

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