COS 109 Lab 8: Privacy and Security     (Last one!)

Sat Nov 4 11:31:11 EDT 2023

Due midnight Sunday November 19

This is the last lab. Have fun.

Privacy is much in the news of late, with concerns ranging from identity theft through government surveillance to commercial exploitation of information about our purchases, our interests, our activities, our friends, and everything else. This lab will explore some issues of privacy and access to information.

This is a comparatively open-ended lab, so you may well find ambiguities and fuzzy bits. Don't worry about them, since this is meant to be for exploration rather than precise answers. But please make suggestions to help us improve the lab for next time.

This lab is intended to be more than a Google and Wikipedia exercise; you must cast your net more widely, by using other search engines and other information sources. You will be graded partly on how well you do this, so tell us for each thing what tools you used and how well they worked. Among the alternative search engines you might try are (in alphabetical order): Bing, Brave, Dogpile, DuckDuckGo, Yahoo, and Yandex. You can also try Baidu; it's in Chinese but there are sites that let you use it in in English. Anything else is fine too.

There are also sites that do telephone number and address lookup or that maintain public records; financial sites like Yahoo finance and Google finance provide access to holdings and trading by insiders (which is legal under some circumstances); and of course social networks like Facebook, Instagram and LinkedIn reveal a lot about their users. Explore; that's part of the exercise. You might find it more productive to spread the lab over a couple of days so you have time to think about possibilities.

As you go along, we want you to collect your observations and comments in a Google Doc. When you're done, save it as a PDF file and upload it to Gradescope.

Use this Google Doc template so we have some uniformity among the submissions.

Access this doc now and begin to edit it. In the following, when we ask you to "report," we're looking for a reasonably organized but not too long description. The questions in the text are meant to start you thinking, but need not be answered literally.

We're not going to grade your writing, but you'll leave a better impression if there aren't too many spelling mistakes, flagrant grammar errors, random formatting, and so on. It's ok to summarize with lists rather than complete sentences, but try to distill the essence of what you've seen rather than just copying and pasting.

You can do this lab anywhere. Some threats primarily affect PCs running Windows, but you should always be cautious, no matter what system you are running. And of course the risks are similar for cellphones, which we're not discussing here. Keep that in mind.

Part 1: Personal Information

For this section, you should use at least three sources, not just Google.

How much can you learn about someone just by searching online information? For yourself or a member of your family or someone else close to you, see how much you can discover about that person online. Examples of the kind of information you might look for include home address, telephone number, age, birthday, education, employment, political contributions, voter registration, sports and hobbies, organizations and memberships, price of their home, names of other family members (like mother's maiden name, for example), activities and interests. Can you find a picture? Was it one that you knew about?

It might be possible to get information by searching for a phone number or street address or social security number. (It's a bad idea to search for your own SSN!) Do phone numbers or addresses reveal family names? Is information always consistent?

Can you find a good picture of your home (or a friend's) with maps from Google, Microsoft or Apple? Which one of these gives the best image? Can you make out your car or some other possession? How much might the house be worth? See, for example, Zillow. If you visit Zillow, what kinds of addresses does it show you without being asked? How does Zillow compare to Trulia? Which one appears to reveal more information, or are they about the same?

What does your Facebook page reveal about you that you find surprising or worth thinking about?

There's no need to go overboard on this; the goal is definitely not to invade anyone's privacy, but to get a sense of the accessibility of ostensibly private information.

  • Who said "If you have something that you don't want anyone to know, maybe you shouldn't be doing it in the first place,"" and in what setting? (You might think about whether this is taken out of context?)
  • Who said "You have control over every single thing that you've shared on Facebook" and in what setting? (You might think about whether it's true.)
  • Which of the search engines listed above appear to be using results from some other search engine?
  • List the information that you were able to find about your chosen individual and what tools you used to find it. Don't include actual phone numbers or street addresses in your report; other information like city of residence, political affiliation and contributions, memberships, and so on is fair game.
  • Part 2: What Else Do They Know About You?

    As we saw in class, the mere act of visiting a web site reveals information about you. There are a variety of sites that report back to you about what information your visit reveals, or about what vulnerabilities your system appears to have. Visit some of these and see what they tell you.

    Search for some service or store with several search engines and see how accurately they geo-locate you. Look for significant differences in apparent accuracy among Google, Bing and other search engines.

    The specific combination of which browser you use, what fonts you have available, and a dozen other bits of information can identify you uniquely, or almost so, to a surprising degree. Visit Cover Your Tracks and Am I Unique? How unique are you? Try it with two different browsers.

  • What did you learn about geographical location data? List three sites that you found that appeared to guess your location and report how precisely they had you located.
  • What did CoverYourTracks and AmIUnique say? List the two browsers and the number of bits of identifying information reported by CoverYourTracks, and other interesting or useful insight from AmIUnique.
  • Part 3: Cookie Crumbs

    We've talked about how cookies can be used to track what web sites you visit, especially "third-party" cookies (that is, cookies that come from someone other than the web site you accessed directly) that aggregate and correlate information about your visits to apparently unrelated sites.

    First, how many cookies do you currently have? Record the rough count, and whether this is before or after you removed cookies after the lecture about them. The easiest way to find cookies is to use the browser. In Firefox on a Mac, use Preferences and the Privacy & Security tab. In Safari, Preferences / Privacy. In Chrome, Preferences / Privacy and Security / Cookies and other site data / See all cookies and site data.

    Now remove all cookies. Set your browser preferences to allow all cookies, then visit half a dozen major sites (media, sports and e-commerce sites are good for this, as are search engines and even universities). Check how many cookies a typical visit deposits.

    For sites that you visit regularly, see whether they deposit third-party cookies. (In the unlikely event that your regular sites don't have third-part cookies, you can try,,, and so on.)

    Experiment to see whether the third-party blocking mechanism of your browser works the way you expect it to, by first allowing such cookies, then removing all, setting up blocking, and revisiting sites.

  • How many cookies were there on your computer when you started the lab? How many cookies does a typical visit deposit? What was the most distant expiration date?
  • Did you find third-party cookies? Are there sites that you don't think you have visited directly?
  • Part 4: Tracking the Trackers

    The site Blacklight is a vivid demonstration of how much tracking goes on at any given website. For example, it reports that it found 34 trackers and 79 cookies at least a dozen different sites at; was similar, with 40 trackers and 105 cookies from over 20 sites, including some that attempt to evade cookie blockers. Unfortunately, Blacklight seems to be permanently broken, at least for me.

    Fou Analytics is analogous, but gives a rather different view of the trackers on a given web page, and sometimes includes actual dollar values for how much an advertiser will pay when you click on one of their links or images. Unfortunately, it seems to work only erratically for me; maybe you will have better luck, but don't waste much time on it.

    Do some exploring with Blacklight, Fou Analytics, and any other tools that you like. and see what kinds of tracking you are potentially vulnerable to. Explore some plausible sites that you do or might visit. (If you turn on defenses like ad blockers, these horror shows won't affect you nearly as much.)

  • What were the two most tracker- and cookie-intensive sites you found.
  • Did you find you find any site that included instances of all seven tracking categories that Blacklight reports?
  • Part 5: Defenses and Countermeasures (1)

    Private Browsing or Incognito Mode in browsers is a partial solution to some tracking problems. An incognito window will delete cookies, history, and most other data that was created while you were browsing with that window, but only from your own computer. If you did anything that could identify you at the various servers you visited, that is still recorded somewhere. And your ISP knows what sites you visited as well. Basically all that incognito mode does is to remove the local record of what you did, so it doesn't make you invisible and unidentifiable, just that there's not much trace of your activities on your own computer (which explains its informal name, "porn mode").

    In an incognito window, visit some sites that will deposit cookies; verify that there are cookies. (News, sports and shopping sites are good.) Delete the window, then open a new incognito window and check to see whether there are any cookies preserved from the last time.

    The Tor browser is one of the best tools for maintaining some anonymity and privacy on the web. Tor is a version of Firefox that uses encryption and a network of relay computers to ensure that the sites that you browse to can not determine your IP address and thus (if you use it properly) are unable to identify you.

    Download and install the Tor browser if you have not already done so; you can find it here.

  • Visit from your regular browser. What location does it provide the weather forecast for?
  • Open a private browsing or incognito window in your regular browser. Visit What location does it provide the weather forecast for?
  • Now visit using Tor. What location does it provide the weather for? Quit Tor, restart it, and repeat the weather experiment several times. What locations are reported? How different are they?
  • Part 6: Defenses and Countermeasures (2)

    As we discussed in class, there are ways to limit your risks and the amount of information that you reveal. Virus checkers are important, but for ordinary browsing there are plenty of others as well.

    Many web sites insist that you provide a working email address before they will let you register or access some service. 10MinuteMail provides a useful service: it gives you an email address that's valid for 10 minutes and shows you whatever mail arrives during that time; that lets you retrieve the registration key or whatever, without giving away a real address. Two alternatives are Mailinator and Yopmail, which lets you invent your own email address, and retains mail for that address for a week. Try a couple of these services. Determine how long it takes for mail to arrive and how long it persists. (I've had the best luck with mailinator but your mileage may vary.)

    Check your own environment. For your regular browser record your default settings for cookies, filename extensions, JavaScript, popups, automatic updates, downloading, software, installation, programs that start automatically, etc. If your mail reader provides a previewer that interprets HTML and thus is subject to web bugs, try sending yourself mail with a reference to an image in your public_html directory, i.e.,, to see whether the image is retrieved and displayed.

    Check what plug-ins and add-ons are already installed in your browser. Among those you might consider adding are AdBlock Plus, uMatrix Origin, NoScript, Privacy Badger, and Ghostery; each reduces your exposure to various kinds of tracking and potentially harmful content. As a bare minimum, you should run Ghostery and Adblock Plus or uMatrix Origin.

    Install Ghostery, which works in most browsers. This extension detects and disables JavaScript trackers, which would otherwise report your page visits and activities to advertising aggregators. Determine how many trackers Ghostery reports that it is blocking. Visit some sites to see how many trackers are in use. Try to find the highest number possible; there might even be a small and worthless prize for the person who finds the worst offender.

    Reconsider your Facebook privacy settings. Bear in mind that most Facebook information is readily available outside your own list of friends and networks; the same goes for other social networks, including Instagram and WhatsApp (owned by Facebook), Snapchat, Twitter, and LinkedIn (owned by Microsoft).

  • What was the result of your experiments with temporary mail services? Which one do you prefer and why?
  • What operating system are you running? What browser do you normally use?
  • What did you learn from Ghostery? What was the largest number of trackers, and at what site?
  • Report on how you have your defenses configured for your most frequently used web browser.
  • Submitting your Work

    Finally, if you saw anything interesting or suspicious that we didn't ask about specifically, or if you have any thoughts on how to improve this lab, we'd like to hear them. There are a couple of wrapup questions in the template that address this:

  • What changes if any did you make to your online settings and behavior as a result of doing this lab?
  • [optional] What changes might we make to the lab to improve it?
  • Thanks.

    When you're all done, convert your Google Doc to lab8.pdf and upload it to Gradescope. No need to put anything on cPanel.