Privacy Challenges in Online Targeted Advertising

137 Pages·2017·1.9 MB·English

Privacy Challenges in Online Targeted Advertising
Minh-Dung Tran
To cite this version:
Minh-DungTran. PrivacyChallengesinOnlineTargetedAdvertising. ComputersandSociety[cs.CY].
Université de Grenoble, 2014. English. ￿NNT: 2014GRENM053￿. ￿tel-01555362￿
HAL Id: tel-01555362
https://theses.hal.science/tel-01555362
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THÈSE
Pour obtenir le grade de
DOCTEUR DE L’UNIVERSITÉ DE GRENOBLE
Spécialité : Informatique
Arrêtéministérial:7août2006
Présentéepar
Minh-Dung Tran
Thèse dirigée par Dr. Claude Castelluccia
et codirigée par Dr. Mohamed-Ali Kaafar
préparée au sein de l’INRIA Rhônes-Alpes, équipe Privatics
et de l’École Doctorale Mathématiques, Sciences et Technologies de
l’Information, Informatique
Privacy Challenges in Online Tar-
geted Advertising.
Thèse soutenue publiquement le 13 Novembre 2014,
devant le jury composé de :
Pr. Martin Heusse
GrenobleINP-Ensimag,Président
Dr. Paul Francis
MaxPlanckInstituteforSoftwareSystems,Rapporteur
Dr. Marc-Olivier Killijian
CNRS,Rapporteur
Dr. Vincent Toubiana
CNIL,Examinateur
Dr. Claude Castelluccia
Inria,Directeurdethèse
Dr. Mohamed-Ali Kaafar
Inria,Co-Directeurdethèse

Abstract
In modern online advertising, advertisers tend to track Internet users’ activities and use
these tracking data to personalize ads. Even though this practice - known as targeted
advertising-bringseconomicbenefitstoadvertisingcompanies,itraisesseriousconcerns
aboutpotentialabusesofusers’sensitivedata. Whilesuchprivacyviolations,ifperformed
by trackers, are subject to be regulated by laws and audited by privacy watchdogs, the
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consequencesofdataleakagefromthesetrackerstootherentitiesaremuchmoredi cultto
detectandcontrol. Protectinguserprivacyisnoteasysincepreventingtrackingundermines
thebenefitsoftargetedadvertisingandconsequentlyimpedesthegrowthoffreecontent
and services on the Internet, which are mainly fostered by advertising revenue. While
short-termmeasures,suchasdetectingandfixingprivacyleakagesincurrentsystems,are
necessary,thereneedstobealong-termapproach,suchasprivacy-by-designadmodel,to
protectuserprivacybypreventionratherthancure.
In the first part of this thesis, we study several vulnerabilities in current advertising
systems that leak user data from advertising companies to external entities. First, since
targeted ads are personalized to each user, we present an attack exploiting these ads on
the fly to infer user private information that have been used to select ads. Second, we
investigatecommonadexchangeprotocols,whichallowcompaniestocooperateinserving
ads to users, and show that advertising companies are leaking user private information,
suchaswebbrowsinghistory,tomultiplepartiesparticipatingintheprotocols. Theseweb
browsinghistories aregiventothese entitiesatsurprisingly lowprices,reflecting thefact
thatuserprivacyisextremelyunderestimatedbytheadvertisingindustry.
Inthesecondpartofthethesis,weproposeaprivacy-by-designtargetedadvertising
model which allows personalizing ads to users without the necessity of tracking. This
model is specifically aimed for the two newly emerging ad technologies - retargeting
advertisingandadexchange. Weshowthatthismodelprovidesstrongprotectionforuser
privacywhilestillensuringadtargetingperformanceandbeingpracticallydeployable.
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Idedicatethisthesistomywife,MinhTrang,
andmylittleson,MinhAnh.
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Acknowledgments
Firstandforemost,Iwouldliketothankmyfamilyfortheirunconditionalloveandsupport.
ffi
They have been always beside me to share and to help me overcome the most di cult
momentsinthisjourney.
Second,IwouldliketoexpressmysincereappreciationtomyadvisorClaudeCastel-
luccia,whogavemetheopportunitytoworkinthisinterestingtopic,forhisgreatguidance
andhelpduringmyPhD.Iwouldalsoliketothankmyco-advisor,Mohamed-AliKaafar
forhishelpandadvice,especiallyatthebeginningofmyPhDlife. Iwouldliketothank
GergelyAcsfortheinvaluablediscussionswehadwhichhelpedmesignificantlyadvance
inmywork.
IamverythankfultoallmycolleaguesatINRIAingeneral,andinPrivaticsteamin
particular, for their collaboration and formaking my time at INRIA enjoyable. I extend
manythanksalsotoallmyfriendsfortheirsupportandthegreatmomentswehaveshared
inlife.
Iwouldliketoexpressmygratitudetomydoctoralcommitteefortheirhelpfulcom-
mentsanddiscussions.
Finally, I gratefully acknowledge the financial support of my studies by the French
MinistryofNationalEducation.
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Contents
1 Introduction 1
1.1 PrivacyChallengesinTargetedAdvertising . . . . . . . . . . . . . . . . 1
1.2 IdentifyingTrackers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 PrivacyLeaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 Privacy-EnhancingInitiatives . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4.1 RegulationandSelf-Regulation . . . . . . . . . . . . . . . . . . 6
1.4.2 Blocking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4.3 PrivacyPreservingTargetedAdvertising . . . . . . . . . . . . . . 8
1.5 Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.6 Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Background: OnlineTrackingandPrivacy 11
2.1 TrackingTechnologies . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.1.1 CollectionTechniques . . . . . . . . . . . . . . . . . . . . . . . 12
2.1.2 Identifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.1.3 BehavioralInformation . . . . . . . . . . . . . . . . . . . . . . . 15
2.2 WhatTheyKnow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.3 Identifiability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3.1 PseudonymousIdentityCanBeLinkedwithRealIdentity . . . . 18
2.3.2 DataDe-anonymization . . . . . . . . . . . . . . . . . . . . . . 19
2.4 WhyWeShouldCareaboutOnlinePrivacy . . . . . . . . . . . . . . . . 19
2.4.1 CounterArguments . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.4.2 PotentialRisksofPrivacyViolation . . . . . . . . . . . . . . . . 20
2.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3 RelatedWork 25
3.1 TrackingtheTrackers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.1.1 PrevalenceofTracking . . . . . . . . . . . . . . . . . . . . . . . 26
3.1.2 TrackingTechniques . . . . . . . . . . . . . . . . . . . . . . . . 26
3.2 TrackingProtectionTechniques . . . . . . . . . . . . . . . . . . . . . . 27
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