Chapter: Security in Computing : Privacy in Computing

Spyware

Cookies are tracking objects, little notes that show where a person has been or what a person has done. The only information they can gather is what you give them by entering data or selecting an object on a web page. As we see in the next section, spyware is far more powerfuland potentially dangerous.

Spyware

 

Cookies are tracking objects, little notes that show where a person has been or what a person has done. The only information they can gather is what you give them by entering data or selecting an object on a web page. As we see in the next section, spyware is far more powerfuland potentially dangerous.

 

Cookies are passive files and, as we have seen, the data they can capture is limited. They cannot, for example, read a computer's registry, peruse an e-mail outbox, or capture the file directory structure. Spyware is active code that can do all these things that cookies cannot, generally anything a program can do because that is what they are: programs.

 

Obviously for sensitive information, such as credit card number or even name and address, the site should encrypt or otherwise protect the data in the cookie. It is up to the site what kind of protection it wants to apply to its cookies. The user never knows if or how data are protected.

 

The path and domain fields protect against one site's being able to access another's cookies. Almost. As we show in the next section, one company can cooperate with another to share the data in its cookies.

 

Third-Party Cookies

 

When you visit a site, its server asks your browser to save a cookie. When you visit that site again your browser passes that cookie back. The general flow is from a server to your browser and later back to the place from which the cookie came. A web page can also contain cookies for another organization. Because these cookies are for organizations other than the web page's owner, they are called third-party cookies.

 

DoubleClick has built a network of over 1,500 web sites delivering content: news, sports, food, finance, travel, and so forth. These companies agree to share data with DoubleClick. Web servers contain pages with invisible ads from DoubleClick, so whenever that page is loaded, DoubleClick is invoked, receives the full invoking URL (which may also indicate other ads to be loaded), and is allowed to read and set cookies for itself. So, in essence, DoubleClick knows where you have been, where you are going, and what other ads are placed. But because it gets to read and write its cookies, it can record all this information for future use.

 

Here are some examples of things a third-party cookie can do.

 

Count the number of times this browser has viewed a particular web page.

 

Track the pages a visitor views, within a site or across different sites.

 

Count the number of times a particular ad has appeared.

 

Match visits to a site with displays of an ad for that site.

 

Match a purchase to an ad a person viewed before making the purchase.

 

Record and report search strings from a search engine.

 

Of course, all these counting and matching activities produce statistics that the cookie's site can also send back to the central site any time the bug is activated. And these collected data are also available to send to any other partners of the cookie.

 

Let us assume you are going to a personal investing page which, being financed by ads, contains spaces for ads from four stockbrokers. Let us also assume eight possible brokers could fill these four ad slots. When the page is loaded, DoubleClick retrieves its cookie, sees that you have been to that page before, and also sees that you clicked on broker B5 sometime in the past; then DoubleClick will probably engineer it so that B5 is one of the four brokers displayed to you this time. Also assume DoubleClick sees that you have previously looked at ads for very expensive cars and jewelry. Then full-priced brokers, not discount brokerages, are likely to be chosen for the other three slots. DoubleClick says that part of its service is to present ads that are the most likely to be of interest to the customer, which is in everybody's best interest.

 

But this strategy also lets DoubleClick build a rich dossier of your web surfing habits. If you visit online gambling sites and then visit a money-lending site, DoubleClick knows. If you purchase herbal remedies for high blood pressure and then visit a health insurance site, DoubleClick knows. DoubleClick knows what personal information you have previously supplied on web forms, such as political affiliation, sexual matters, religion, financial or medical status, or identity information. Even without your supplying private data, merely opening a web page for one political party could put you on that party's solicitation list and the other parties' enemies lists. All this activity goes under the general name of online profiling. Each of these pieces of data is available to the individual firm presenting the web page; DoubleClick collects and redistributes these separate data items as a package.

 

Presumably all browsing is anonymous. But as we have shown previously, login IDs, e-mail addresses, and retained shipping or billing details can all lead to matching a person with this dossier, so it is no longer an unnamed string of cookies. In 1999, DoubleClick bought Abacus, another company maintaining a marketing database. Abacus collects personal shopping data from catalog merchants, so with that acquisition, DoubleClick gained a way to link personal names and addresses that had previously been only patterns of a machine, not a person.

 

Cookies associate with a machine, not a user. (For older versions of Windows this is true; for Unix and Windows NT, 2000, and XP, cookies are separated by login ID.) If all members of a family share one machine or if a guest borrows the machine, the apparent connections will be specious. The second problem of the logic concerns the correctness of conclusions drawn: Because the cookies associate actions on a browser, their results are incomplete if a person uses two or more browsers or accounts or machines. As in many other aspects of privacy, when the user does not know what data have been collected, the user cannot know the data's validity.

 

Web Bugs: Is There an Exterminator?

 

The preceding discussion of DoubleClick had a passing reference to an invisible image. Such an image is called a clear GIF, 1 x 1 GIF, or web bug. It is an image file 1 pixel by 1 pixel, so it is far too small to detect by normal sight. To the web browser, an image is an image, regardless of size; the browser will ask for a file from the given address.

 

The distinction between a cookie and a bug is enormous. A cookie is a tracking device, transferred between the user's machine and the server. A web bug is an invisible image that invites or invokes a process. That process can come from any location. A typical advertising web page might have 20 web bugs, inviting 20 other sites to drop images, code, or other bugs onto the user's machine. All this occurs without the user's direct knowledge or certainly control.

 

Unfortunately, extermination is not so simple as prohibiting images smaller than the eye can see, because many web pages use such images innocently to help align content. Or some specialized visual applications may actually use collections of minute images for a valid purpose. The answer is not to restrict the image but to restrict the collection and dissemination of data.

 

Spyware

 

Cookies are tracking objects, little notes that show where a person has been or what a person has done. The only information they can gather is what you give them by entering data or selecting an object on a web page. As we see in the next section, spyware is far more powerfuland potentially dangerous.

 

Cookies are passive files and, as we have seen, the data they can capture is limited. They cannot, for example, read a computer's registry, peruse an e-mail outbox, or capture the file directory structure. Spyware is active code that can do all these things that cookies cannot, generally anything a program can do because that is what they are: programs.

 

Spyware is code designed to spy on a user, collecting data (including anything the user types). In this section we describe different types of spyware.

 

Keystroke Loggers and Spyware

 

We have previously referred to keystroke loggers, programs that reside in a computer and record every key pressed. Sophisticated loggers discriminate, recording only web sites visited or, even more serious, only the keystrokes entered at a particular web site (for example, the login ID and password to a banking site.)

 

A keystroke logger is the computer equivalent of a telephone wiretap. It is a program that records every key typed. As you can well imagine, keystroke loggers can seriously compromise privacy by obtaining passwords, bank account numbers, contact names, and web search arguments.

 

Spyware is the more general term that includes keystroke loggers and also programs that surreptitiously record user activity and system data, although not necessarily at the level of each individual keystroke. A form of spyware, known as adware (to be described shortly) records these data and transmits them to an analysis center to present ads that will be interesting to the user. The objectives of general spyware can extend to identity theft and other criminal activity.

 

In addition to the privacy impact, keystroke loggers and spyware sometimes adversely affect a computing system. Not always written or tested carefully, spyware can interfere with other legitimate programs. Also, machines infected with spyware often have several different pieces of spyware, which can conflict with each other, causing a serious impact on performance.

 

Another common characteristic of many kinds of spyware is the difficulty of removing it. For one spyware product, Altnet, removal involves at least twelve steps, including locating files in numerous system folders [CDT03].

 

Hijackers

 

Another category of spyware is software that hijacks a program installed for a different purpose. For example, file-sharing software is typically used to share copies of music or movie files. Services such as KaZaa and Morpheus allow users to offer part of their stored files to other users. According to the Center for Democracy in Technology [CDT03], when a user installed KaZaa, a second program, Altnet, was also installed. The documentation for Altnet said it would make available unused computing power on the user's machine to unspecified business partners. The license for Altnet grants Altnet the right to access and use unused computing power and storage. An ABC News program in 2006 [ABC06] reports on taxpayers whose tax returns were found on the Internet after the taxpayers used a file-sharing program.

 

The privacy issue for a service such as Altnet is that even if a user authorizes use of spare computing power or sharing of files or other resources, there may be no control over access to other sensitive data on the user's computer.

 

Adware

 

Adware displays selected ads in pop-up windows or in the main browser window. The ads are selected according to the user's characteristics, which the browser or an added program gathers by monitoring the user's computing use and reporting the information to a home base.

 

Adware is usually installed as part of another piece of software without notice. Buried in the lengthy user's license of the other software is reference to "software x and its extension," so the user arguably gives permission for the installation of the adware. File-sharing software is a common target of adware, but so too are download managers that retrieve large files in several streams at once for faster downloads. And products purporting to be security tools, such as antivirus agents, have been known to harbor adware.

 

Writers of adware software are paid to get their clients' ads in front of users, which they do with pop-up windows, ads that cover a legitimate ad, or ads that occupy the entire screen surface. More subtly, adware can reorder search engine results so that clients' products get higher placement or replace others' products entirely.

 

180Solutions is a company that generates pop-up ads in response to sites visited. It distributes software to be installed on a user's computer to generate the pop-ups and collect data to inform 180Solutions of which ads to display. The user may inadvertently install the software as part of another package; in fact, 180Solutions pays a network of 1,000 third parties for each installation of its software on a user's computer. Some of those third parties may have acted aggressively and installed the software by exploiting a vulnerability on the user's computer [SAN05]. A similar product is Gator or Claria or GAIN from the Gator Corporation. Gator claims its software is installed on some 35 million computers. The software is designed to pop up advertising at times when the user might be receptive, for example, popping up a car rental ad right after the user closed an online travel web site page.

 

There is little analysis of what these applications collect. Rumors have it that they search for name, address, and other personal identification information. The software privacy notice from Gain's web site lists many kinds of information it may collect:

 

Gain Privacy Statement

 

 

             WHAT INFORMATION DOES GAIN COLLECT?

 

GAIN Is Designed to Collect and Use Only Anonymous Information. GAIN collects and stores on its servers anonymous information about your web surfing and computer use. This includes information on how you use the web (including the URL addresses of the web pages you view and how long you view them), non-personally identifiable information you provide on web pages and forms (including the Internet searches you conduct), your response to online ads, what software is on the computer (but no information about the usage or data files associated with the software), system settings, and information about how you use GAIN-Supported Software. For more information about the data we collect, click: www.gainpublishing.com/rdr/73/datause.html.

 

 

"What software is on the computer" and "system settings" seem to cover a wide range of possibilities.

 

Drive-By Installation

 

Few users will voluntarily install malicious code on their machines. Authors of spyware have overcome suspicions to get the user to install their software. We have already discussed dual-purpose software and software installed as part of another installation.

 

A drive -by installation is a means of tricking a user into installing software. We are familiar with the pop-up installation box for a new piece of software, saying "your browser is about to install x from y. Do you accept this installation? Yes / No." In the drive-by installation, a front piece of the software has already been downloaded as part of the web page. The front piece may paste a different image over the installation box, it may intercept the results from the yes / no boxes and convert them to yes, or it may paste a small image over the installation box obliterating "x from y" and replace it with "an important security update from your browser manufacturer." The point is to perform the installation by concealing from the user the real code being installed.

 

38 percent correctly thought it was legal for an online merchant to charge different people different prices at the same time of day.

 

36 percent correctly thought it was legal for a supermarket to sell buying habit data.

 

32 percent correctly thought a price-shopping travel service such as Orbitz or Expedia did not have to present the lowest price found as one of the choices for a trip.

 

29 percent correctly thought a video store was not forbidden to sell information on what videos a customer has rented.

 

A fair market occurs when seller and buyer have complete knowledge: If both can see and agree with the basis for a decision, each knows the other party is playing fairly. The Internet has few rules, however. Loss of Internet privacy causes the balance of knowledge power to shift strongly to the merchant's side.


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