Category Archives: Privacy

A Taxonomy of Social Networking Data

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In July 2010’s issue of IEEE Security & Privacy, Bruce Schneier in a one-page paper presented his taxonomy. It is extremely interesting. My comments are in italics.

  • 1. Service data is the data used to manage the service such as your name.
    You have control on the creation, although you may be obliged to give sometimes real data.
  • 2. Disclosed data is what you post on your own pages.
    You normally have full control on it.
  • 3. Entrusted data is what you post on other people’s pages.
    You have control on the creation, but lose control on its life.
  • 4. Incidental data is what other people post about you.
    You do not have control on the creation, nor on its life. Of course, your entrusted data are incidental data for other people.
  • 5. Behavioral data is data the site collects about your habits by recording what you do and who you do it with.
    This is the “raison d’être” of many social networks. Never forget that there is no free lunch. Most of the business models are based on “selling/using” your profile. You have no control, excepted that you may try to control your behavior.
  • 6. Derived data is data about you that is derived from all the other data.
    This is where the social networks are polishing your profile and thus increasing its value. The more they know you, the more valuable ads/personalized services they will be able to offer. You have definitively no control.

Category 5 and 6 are the most interesting ones from the privacy point of view. How can you control what the social network provider will infer from your activity on the social network.

The reference of the paper is
B. Schneier, “A Taxonomy of Social Networking Data,” IEEE Security and Privacy, vol. 8, 2010, p. 88.

An analysis of Private Browsing Modes in Modern Browsers

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Tuesday, November 2, 2010

Gaurav AGGARWAL, Elie BURZSTEIN, Collin JACKSON and Dan BONEH published an analysis of the private browsing mode in Internet Explorer, 8, Firefox 3.5, Safari 4, and Chrome 5.

What is private browsing mode? According to Mozilla:

Firefox 3.5 and later provide “Private Browsing,” which allows you to browse the Internet without Firefox saving any data about which sites and pages you have visited.

According to the researchers, all four browsers failed. Don’t panic!

The researchers provided a very drastic definition of private browsing that extends further than Mozilla’s one. For instance, they define four types of persistent state changes:

  • Initiated by the web site without user interaction such as cookie, adding entry in the history file…
  • Initiated by a web site but with user interaction such as generating a client certificate, adding a password to the password database
  • Initiated by the user such as adding a bookmark
  • Installing a patch or updating a blocking list

All browsers do a decent job for the first category. Nevertheless, they are less well-performing for the other categories. For instance, all the four browsers retain a SSL certificate generated while in private browsing mode. The certificate will leak the site address.

Most of the people are only concerned with the first category. Thus, they are safe. More paranoid people should study their browser and act correspondingly.

Interestingly, the paper proposed three goals versus a web attacker:

  • A web site cannot link a user visiting in private mode to the same user visiting in public mode
  • A web site cannot link a user in one private session to the same user in another private session.
  • A web site should not be able to guess if the browser is in private mode

They also highlighted an under evaluated risk. Although the browser supports a private mode, it does not mean that the plug-ins act also in private mode. In other words, while the browser is in private mode, your addons may still leak information  :Happy:

The risk of geo-tagging

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Once more, new technology introduced threats on privacy. FRIEDLAND Gerald and SOMMER Robin, in their paper “Cybercasing the Joint: On the Privacy Implications of Geo-Tagging” clearly highlight the new risks.

Many high end phones, such as iPhones, come with GPS. Undoubtfully, GPS is a great feature. Once you used it, you cannot live anymore without. Nevertheless, the combination of GPS and camera is a problem. Currently, all such devices embed a geo-tag, i.e. the precise location, in the metadata of pictures shot by the camera. And many of such pictures end up on Flicker, Facebook and Craig List. This metadata can be easily extracted through standard tools.

In other words, if you publish on Internet a picture of your house taken with your iPhone, it will be extremely easy for anybody to locate you for instance using Google Street View. The paper presents a very illustrative example.

Of course, you can disable the geo-tagging. But, (1) you must be aware of the threat, and then (2) find how to disable it. The solution should be that the manufacturers make this feature as opt-in, i.e. disabled by default. Very unlikely, because manufacturers load the devices with new features ready to work.

If you have a mobile phone with GPS, think about it. Personnaly, I know what I would do.

I publish, I think

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Je publie, je réfléchis (I publish, I think) is the name of a French Internet site which aims at sensitizing people (mainly young audience) on the risks of publishing things on the Net. It is designed by the CNIL (French authority for IT and liberty)

It provides ten good recommendations before publishing, such as:

  • Ask yourself if you would do the same in “real” life
  • read the terms and conditions of social web sites. This is probably the less realistic one. It is a tough job. Did you do it yourself when for instance joining LinkedIn? I confess that I did not 
  • Don’t publish contents that may harm the reputation of somebody else
  • Use a pseudo that you communicate only to your close friends…

Interestingly, the site is linked to a serious game that describes a realistic scenario and gives some hints to avoid the problems. If you have youngsters, send them to this site.

Unfortunately, the site is only in French. Does somebody know an equivalent site in English?

Thanks to OH to have pointed me to the site. 

Updated on 3 Dec 14:  The site is not anymore online

Facebook – Another breach in the wall

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This is the title of a presentation that George Petre gave recently at the MIT spam conference. George is the head of the Threat Intelligence Team of anti-virus company BitDefender.

His team experimented the use of social networks as spam vector. And the results are impressive (frightening?). Social networks are great for spams.

One of the side results of the study is the evaluation of user acceptance of new ”friends”. They created three types of profiles. The first one had the minimal allowed details (without picture), the second one had a picture and some more details and the third one was extremely complete.

Just one hour after starting to add people to each profile, we managed 23 connections with the 1st profile, 47 with the 2nd profile and 53 with the 3rd profile.

Amazing! You don’t even not need to be a social engineer.

And of course, once you are a friend, people have a natural tendency to trust you and accept any of your proposed links.

The full paper is available here. If you are worried about social networks, read this paper and you will be even more worried. The remedy seems simple: accept as friend only people that you know and trust. Unfortunately, this is contrary to the drive to have a high score of friends.

Do people care about privacy? Blippy

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Privacy is a hot topic. Many people fight to preserve our privacy. On the other side, many people build services that destroy this privacy. According to me, social networks are among the natural predators of privacy.

I went through a new site: Blippy. First, I thought it was a joke. But no, it is real. And some serious reviewers (such as techcrunch) appreciated it.

Blippy proposes to display every purchase you will do with one credit card. It provides the details of the transaction: when, where, how much and the details of the purchase. The objective is that people discuss with you about your purchases such as asking for evaluation, tips or giving advices.

Where is the problem? Social Engineering!! Tell me what you buy, and I will have a far better knowledge of who you are, a rough estimate of your incomes… If you purchase travel tickets, I will know when you will not be at home… Are people who subscribe to this site aware of this risk?

Of course, the site has a section about privacy. It is worth reading!

Would you enroll on such sites?

Augmented Identity

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Technologies were around. Social networks become prevalent. People are not aware of risks (or at least they are less paranoid than me 🙂 ). Somebody had to do it.

The Astonishing Tribe (TAT) did shake all the elements together and presented recognizr. Using a mobile phone to capture a picture of the person, recognizr extracts 3D parameters of the face and sends it to a server. The server uses a face recognition software and looks in social networks to identify the person and provide data.

TAT was privacy aware. Thus, the system works on strict opt in. In other words, you must register to the system to be recognized.

TAT is privacy aware, but what prevents another company/agency/group to design a similar software and scout the social networks without the consent of the people? Law enforcement? Well, it uses only public data. The data that you/we posted on the Internet.

This application was inevitable. Everything was available. Nevertheless, it scares me. Once more, be very cautious on what personal data you post on the Internet.