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report.lyx
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report.lyx
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#LyX 2.1 created this file. For more info see http://www.lyx.org/
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\pdf_title "Master’s thesis"
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\begin_body
\begin_layout Title
Master’s thesis
\begin_inset Newline newline
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status open
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(Preliminary title)
\end_layout
\end_inset
\begin_inset Newline newline
\end_inset
Swedes Online: You Are More Tracked Than You Think
\end_layout
\begin_layout Author
Joel Purra
\begin_inset Newline newline
\end_inset
\begin_inset CommandInset href
LatexCommand href
target "mig@joelpurra.se"
type "mailto:"
\end_inset
, joepu444
\begin_inset Newline newline
\end_inset
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LatexCommand href
target "http://joelpurra.com/"
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\begin_inset Newline newline
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+46 70 352 1212
\end_layout
\begin_layout Date
\begin_inset ERT
status open
\begin_layout Plain Layout
\backslash
versionandtoday
\end_layout
\end_inset
\end_layout
\begin_layout Abstract
While browsing web sites third-party resources track your online habits,
which can be considered an invasion of privacy.
It was previously unknown how many third-party resources, known trackers
and tracker companies are represented on an average web site.
While downloading over
\begin_inset ERT
status open
\begin_layout Plain Layout
\backslash
numprint{150000}
\end_layout
\end_inset
globally popular as well as random .com/.net/.se/.dk web sites, in-browser
HTTP traffic was recorded and analyzed.
Data shows that known third-party resources including known trackers have
a presence on over 70%
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
70-93%
\end_layout
\end_inset
of sites, that Google has a presence of over 47%
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
47-90%
\end_layout
\end_inset
and that third-party hosted
\emph on
content
\emph default
such as video, scripts and fonts make up a large portion of known trackers.
\end_layout
\begin_layout Chapter*
Introduction
\end_layout
\begin_layout Standard
How many companies are tracking you online, and how much information does
the average Swede leak while using popular .se websites? Many, and a lot
- more than you may think.
Large organizations
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
like A, B and C
\end_layout
\end_inset
are able to connect the dots you leave behind during everyday usage, and
construct a persona that reflects you from their perspective.
Have you told your family, friends or colleagues about your gambling addiction,
your sex toy purchases or your alcoholism?
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Replace with different scary personal information?
\end_layout
\end_inset
Even if you did not tell anyone your deepest secrets, these companies might
conclude that they can put labels on you by looking at everything you do
online.
And now they are selling it as hard facts behind the scenes.
\end_layout
\begin_layout Standard
While browsing the web users are both actively and passively being tracked
by multiple companies, for the purpose of building a persona for targeted
advertising.
Sometimes the data collection is visible, as in social network sites and
questionnaires, but it is most common in the form of different kinds of
external resources which may or may not serve a purpose other than keeping
track of your every click.
Secure connections between server and client help against passive data
collection along the network path, but not against site owners allowing
in-page trackers.
Tracking code is installed on web pages that have adverts as well as those
that do not - the spread and reach of tracking across web pages and domains
of different kinds increases the quality of the user data collected and
inferred, making it more valuable for advertising purposes.
With the extent of the use of trackers and other external resources largely
unknown and ever evolving, what is already known raises privacy concerns
- data considered personal leak without the user's knowledge or explicit
permission and end up in privately owned databases for further distribution.
Data collection is the new wild west, and you are the new cattle.
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Or Klondike and gold?
\end_layout
\end_inset
\end_layout
\begin_layout Standard
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Mention related work?
\end_layout
\end_inset
\end_layout
\begin_layout Standard
This thesis uses large-scale measurements to characterize how different
kinds of domains in Sweden and internationally use web site resources.
Front pages of approximately
\begin_inset ERT
status open
\begin_layout Plain Layout
\backslash
numprint{150000}
\end_layout
\end_inset
random .se, .dk, .com, .net domains and Swedish, Danish and Alexa's top domains
were visited and their resources, including those dynamically loaded, recorded.
Each domain was accessed both with insecure HTTP and secure HTTPS connections
to provide a comparison.
Resources were grouped by mime type, URL protocol, domain, if it matches
the domain the request originated from and compared to lists of known trackers
and organizations.
\end_layout
\begin_layout Itemize
Software for automated, repeatable retrieval and analysis of large amounts
of web sites was developed, and released as open source (see
\begin_inset CommandInset ref
LatexCommand vref
reference "chap:Software"
\end_inset
).
Datasets based on publicly available domain lists have been released for
scientific scrutinization.
\begin_inset Foot
status open
\begin_layout Plain Layout
\begin_inset CommandInset href
LatexCommand href
target "http://joelpurra.com/projects/masters-thesis/"
\end_inset
\end_layout
\end_inset
The data allows analysis of web sites' HTTP requests including the use
of resources internal versus external to the entry domain, which the most
common confirmed tracker organizations are, what spread they have and how
much the average internet user can expect to be tracked by visiting some
of the most important and popular sites in Sweden, Denmark and worldwide.
\end_layout
\begin_layout Itemize
First, adaption of HTTPS for different domains is characterized from a Swedish
perspective.
The adaption between classes of domains within Sweden, as well as against
popular international domains are compared.
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Highlight some key findings and their implications.
\end_layout
\end_inset
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Write about users' (in-)ability to protect their own privacy using HTTPS.
\end_layout
\end_inset
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Insert reference to results chapter.
\end_layout
\end_inset
\end_layout
\begin_layout Itemize
Second, the use of third-party trackers and other third-party services for
different classes of domains, is analyzed.
Using public lists of potential tracker domains, we analyze and compare
the wide spread adaption of these services across domains within Sweden,
as well as internationally.
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Highlight some key findings and their implications.
\end_layout
\end_inset
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Insert reference to results chapter.
\end_layout
\end_inset
\end_layout
\begin_layout Standard
\begin_inset CommandInset toc
LatexCommand tableofcontents
\end_inset
\end_layout
\begin_layout Standard
\begin_inset FloatList table
\end_inset
\end_layout
\begin_layout Chapter
Background
\end_layout
\begin_layout Standard
In everyday web browsing, browsers routinely access a lot of material from
other domains or services than the one visited
\begin_inset CommandInset citation
LatexCommand cite
key "Feldmann:2004:MEI:1028788.1028833"
\end_inset
.
These external resources vary from content that the user explicitly want
to obtain, to implicitly loaded third-party services, ads, and non-visible
resources with the sole purpose of collecting user data and statistical
material
\begin_inset CommandInset citation
LatexCommand cite
key "Krishnamurthy:2006:CMC:1135777.1135829"
\end_inset
.
All are downloaded on behalf of the user with no or few limitations, and
oftentimes without the user's need, understanding and explicit consent.
These external resources can all be seen as browsing habit trackers, whose
knowledge and power increase with any additional visits to other domains
or services loading the same resources
\begin_inset CommandInset citation
LatexCommand cite
key "Malandrino:2013:PAI:2517840.2517868"
\end_inset
.
While privacy is both hard to define as well as relative to perspective
and context, there is a correlation between trackers and online privacy;
more trackers means it becomes harder to control the flow of personal informati
on and get an overview of where data ends up
\begin_inset CommandInset citation
LatexCommand cite
key "Smith:2011aa,Bylund:2013:978-91-87379-12-3:integritet"
\end_inset
.
\end_layout
\begin_layout Section
Trackers are a commercial choice
\end_layout
\begin_layout Standard
While online privacy has been in the spotlight due to recently uncovered
mass surveillance operations, the focus has been on national government
intelligence agencies collecting information around the globe.
Public worry regarding surveillance in Sweden is low.
Only 9% of Swedes say they worry to some degree about government surveillance,
but at 18% twice as many worry about companies' surveillance
\begin_inset CommandInset citation
LatexCommand cite
key "Ahlgren:2014aa"
\end_inset
.
Governments are able to intercept traffic data and metadata by, among several
techniques,
\emph on
covertly
\emph default
hooking into the internet infrastructure and passively listening.
Basic connection metadata can always be collected, but without secure connectio
ns between client and server, any detail in the contents of each request
can be extracted.
In contrast, external resources are approved by and actively installed
by site and service owners, and presented openly to users with basic technical
skills and tools.
Reasons can be technical, for example because distributing resources among
systems improves performance
\begin_inset CommandInset citation
LatexCommand cite
key "Krishnamurthy:2006:CMC:1135777.1135829,Krishnamurthy:2000:AFI:347319.346248"
\end_inset
.
Other times it is because there are positive network effects in using a
third-party social network to promote content and products.
Ads are installed as a source of income.
More and more commonly, allowing a non-visible tracker to be installed
can also become a source of income - data aggregation companies pay for
access to users' data on the right site with the right quantity and quality
of visitors.
Because these external resources are used on behalf of the service, they
are also loaded when end-to-end encryption with HTTPS is enabled for enhanced
privacy and security.
This encryption bypass gives these private trackers more information than
possible with large-scale passive traffic interception, even when there
is a security nullifying mixture of encrypted and unencrypted connections.
\end_layout
\begin_layout Section
What is known by trackers?
\end_layout
\begin_layout Standard
Depending on what activities a user performs online, different things can
be inferred by trackers on sites where they are installed.
For example, a tracker on a news site can draw conclusions about interests
from content a user reads (or choses
\emph on
not
\emph default
to) by tagging articles with refined keywords and creating an interest
graph
\begin_inset CommandInset citation
LatexCommand cite
key "Kumar:2013:GBT:2522548.2523129"
\end_inset
.
The range of taggable interests of course depend on the content of the
news site.
Private and sensitive information leaked to third-party sites during typical
interaction with some of the most popular sites in the world include personal
identification (full name, date of birth, email, ip address, geolocation)
and sensitive information (sexual orientation, religious beliefs, health
issues)
\begin_inset CommandInset citation
LatexCommand cite
key "Malandrino:2013:PAI:2517840.2517868"
\end_inset
.
Social buttons, allowing users to share links with a simple click, are
tracking users whether they are registered, logged in or not
\begin_inset CommandInset citation
LatexCommand cite
key "Roosendaal:2010:likethis"
\end_inset
.
They are especially powerful when the user is registered and logged in,
combining the full self-provided details of the user with their browsing
habits - all within the bounds of the services' privacy policies agreed
to by the user.
Once a user has provided their personal information, it is no longer just
the individual browser or device being tracked, but the actual person using
it - even after logging out
\begin_inset CommandInset citation
LatexCommand cite
key "Kontaxis:2012:PSP:2362793.2362823,Krishnamurthy:2008:CPO:1397735.1397744"
\end_inset
.
This direct association, as opposed to inferred, to the person also allows
for tracking across devices where there is an overlap of services used.
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Find a reference for cross device tracking.
\end_layout
\end_inset
\end_layout
\begin_layout Section
What is the information used for?
\end_layout
\begin_layout Standard
Publishers reserve areas of their web pages for displaying different kinds
and sizes of advertisements alongside content.
Ads chosen for the site may be aligned with the content but it is more
valuable the more is known about the visitors.
Combining and aggregating information from past visitors means that more
information can be assumed about future visitors, on a statistical basis,
which will define the general audience of the site.
To generate even more revenue per displayed ad, individual users are
\emph on
targeted
\emph default
with personalized ads depending on their specific personal data and browsing
history
\begin_inset CommandInset citation
LatexCommand cite
key "Gill:2013:BPF:2504730.2504768"
\end_inset
.
\end_layout
\begin_layout Standard
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Write about data aggregators selling information for other purposes than
advertising.
\end_layout
\end_inset
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
What kind of data can be collected by trackers, and how can they be aggregated
both per person and per group of people?
\end_layout
\end_inset
\end_layout
\begin_layout Standard
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
How much does the average user know about external resources being trackers?
\end_layout
\end_inset
\end_layout
\begin_layout Chapter
Methodology
\end_layout
\begin_layout Standard
Emphasis for the thesis is on a technical analysis, producing aggregate
numbers regarding domains and external resources.
Social aspects and privacy concerns are considered out of scope.
\end_layout
\begin_layout Standard
For methodology details, see
\begin_inset CommandInset ref
LatexCommand vref
reference "chap:Methodology-details"
\end_inset
.
\end_layout
\begin_layout Section
High level overview
\end_layout
\begin_layout Standard
Based on a list of domains, the front page of each domain is downloaded
and parsed the way a user's browser would.
The URL of each requested resource is extracted, and associated with the
domain it was loaded from.
This data is then classified in a number of ways, before being boiled down
to statistics about the entire dataset.
These aggregates are then compared between datasets.
\end_layout
\begin_layout Standard
The thesis is primarily written from a Swedish perspective.
This is in part because .SE has access to the full list of Swedish .se domains,
and part because of their previous work with the
\emph on
.SE Health Status
\emph default
reports.
Focus is to analyze .se domains in the reports, as they have already been
deemed important and results can be incorporated in future reports, and
use other TLDs and domain lists for contrast.
The main non-technical grouping is also based on the same reports; government,
media, financial institutions and other nation-wide publicly relevant organizat
ion groups.
\end_layout
\begin_layout Standard
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Previous expected results, methodology and software chapters trimmed down
into a more compact format; refer to appendix for software/script details.
\end_layout
\end_inset
\end_layout
\begin_layout Section
Domain categories
\end_layout
\begin_layout Standard
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Use of domain names and suffix lists.
\end_layout
\end_inset
\end_layout
\begin_layout Section
Capturing tracker requests
\end_layout
\begin_layout Standard
One assumption is that all external resources can act as trackers, even
for static (non-script) resources with no capabilities to dynamically survey
the user's browser, collecting data and tracking users across domains using
for example the
\begin_inset Flex Code
status collapsed
\begin_layout Plain Layout
referer
\end_layout
\end_inset
(sic) HTTP header
\begin_inset CommandInset citation
LatexCommand cite
key "Krishnamurthy:2006:CMC:1135777.1135829"
\end_inset
.
While there are lists of known trackers, used by browser privacy tools,
they are not 100% effective
\begin_inset CommandInset citation
LatexCommand cite
key "Malandrino:2013:PAI:2517840.2517868,Krishnamurthy:2006:CMC:1135777.1135829"
\end_inset
.
Lists are instead used to emphasize those external resources as
\emph on
confirmed
\emph default
and
\emph on
recognized
\emph default
trackers.
\end_layout
\begin_layout Standard
Resources have not been blocked in the browser during web site retrieval,
but have been matched by URL against a third-party list in the analysis
step.
This way trackers dynamically triggering additional requests have also
been recored, which can make a difference if they access another domain
or another organization's trackers in the process.
\end_layout
\begin_layout Standard
The tracker list of choice is the one used in the privacy tool Disconnect.me,
where it is used to block external requests to (most) known tracker domains.
It consists of
\begin_inset ERT
status open
\begin_layout Plain Layout
\backslash
numprint{2149}
\end_layout
\end_inset
domains, each belonging to one of
\begin_inset ERT
status open
\begin_layout Plain Layout
\backslash
numprint{980}
\end_layout
\end_inset
organizations and five categories: advertising, analytics, content, diconnect
and social
\begin_inset CommandInset ref
LatexCommand eqref
reference "sub:Disconnect's-blocking-list"
\end_inset
.
Not all domains in the list are treated the same by Disconnect.me; despite
being listed as known trackers, the content category
\begin_inset CommandInset ref
LatexCommand eqref
reference "sub:Disconnect-Content"
\end_inset
is not blocked by default in order to not disturb the normal user experience
too much.
The domain level blocking fits well with the thesis' internal versus external
resource reasoning.
Because domains are linked to organizations as well as broadly categorized,
blocking aggregate counts and coverage can form a bigger picture.
\end_layout
\begin_layout Standard
While cookies used for tracking have been a concern for many, they are not
necessary in order to identify most users upon return, even uniquely on
a global level
\begin_inset CommandInset citation
LatexCommand cite
key "Eckersley2009unique"
\end_inset
.
Cookies have not been considered to be an indicator of tracking, as it
can be assumed that a combination of other server and client side techniques
can achieve the same goal as a normal tracking cookie
\begin_inset CommandInset citation
LatexCommand cite
key "G.-Acar:persistent:2014aa"
\end_inset
.
\end_layout
\begin_layout Section
Data collection
\end_layout
\begin_layout Standard
\begin_inset Note Greyedout
status open
\begin_layout Plain Layout
Variation of the old retrieving websites and resources chapter, including
parallelization.
\end_layout
\end_inset
\end_layout
\begin_layout Section
Data analysis and validation
\end_layout