Top sites (and maybe the NSA) track users with “device fingerprinting”

Close to 1.5 percent of the Internet's top websites track users without their knowledge or consent, even when visitors have enabled their browser's Do Not Track option, according to an academic research paper that raises new questions and concerns about online privacy.

The research, by a team of scientists in Europe, is among the first to expose the real-world practice of "device fingerprinting," a process that collects the screen size, list of available fonts, software versions, and other properties of the visitor's computer or smartphone to create a profile that is often unique to that machine. The researchers scanned select pages of the top 10,000 websites as ranked by Alexa and found that 145 of them deployed code based on Adobe's Flash Player that fingerprinted users surreptitiously. When they expanded their survey to the top one million sites, they found 404 that used JavaScript-based fingerprinting. The researchers said the figures should be taken as the lower bounds since their crawlers weren't able to access pages behind CAPTHCAs and other types of Web forms. Mainstream awareness of fingerprinting first surfaced three years ago following the release of research from the Electronic Frontier Foundation.

Device fingerprinting serves many legitimate purposes, including mitigating the impact of denial-of-service attacks, preventing fraud, protecting against account hijacking, and curbing content scraping, bots, and other automated nuisances. But fingerprinting also has a darker side. For one, few websites that include fingerprinting code in their pages disclose the practice in their terms of service. For another, marketing companies advertise their ability to use fingerprinting to identify user behavior across websites and devices. That suggests device fingerprinting may be used much the way tracking cookies are used to follow people as they browse from site to site, even though fingerprinting isn't covered by most laws governing cookies and websites' Do Not Track policies. And unlike user profiling that relies on "stateful" browser cookies that are usually easy to delete from hard drives, most end users have no idea that their computers are being fingerprinted, and they have few recourses to prevent the practice.

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Turkish ‘Delete Virus’ Targets Facebook Users

Facebook continues to be a favorite target for attackers to spread fake wall-post messages or fake scams. Most of the time these fake messages are involved in fake scams that ask users to respond to surveys. Recently, I discovered a Facebook wall post with a malicious website address that was unknowingly shared by a friend. Once infected with this spam, the malicious wall post will also tag all the friends of an infected Facebook user.  Here is the screenshot of a malicious wall post:


The link from this wall post redirects users to a malicious website that hosts malicious code. This site launches its main attack by identifying browsers with the help of the following code:


The preceding code from the malicious site targets Firefox and Chrome browsers on userAgent strings.


If the malware detects Firefox, it presents the following error message in Turkish:


The Google translation of the this message reads:

Please Refresh button, Firefox Add-Update your. Due to system errors and security bugs that are required by pressing the Reload button. Install Firefox Plug-in Update. As long as you have not updated the site faydalanamayacaksýnýz features.

Once clicked, the site installs the malicious “sosyalag.xpi” (XPI extension archive) file for Firefox (from the malicious site) along with a Chrome application from the Google Chrome store (this app has been removed from the store). Here is the JavaScript function used for the Chrome app:



If the malicious site detects Chrome, it will download the malicious file player.exe from the attacker’s dropbox account without asking the user. After using Chrome to visit the site, a victim will see a fake video page:


The malicious site cleverly shows an arrow pointing to the malicious file for download, even though the file has already  arrived. Player.exe makes Chrome install another malicious application by adding an entry for a .crx file from another malicious site under “\Policies\Google\Chrome\ExtensionInstallForcelist\1: “gagalgomhifgcmeciklindhpaihmecgi;” Once an infected user enters Facebook, the malicious code runs JavaScript in the background, infecting further users.

VirusTotal Detection




The XPI extension file for Firefox contains malicious JavaScript code that targets Facebook. Here is screenshot of one of the files:


The name in the preceding script “Virusü Sil” is Turkish, which in English is “Delete Virus.” Malicious sites hosting the files present user with information in Turkish. This campaign is aimed against Turkish Facebook users, but it’s not limited to them. Once someone is infected with these extensions, a victim can spread the same post by tagging their friends.

Facebook has already removed these malicious messages from the infected users’ wall posts. The malicious apps have also been removed from Google Chrome store.

Social Scams – Part 2: How to Clean Up Your Browser and Facebook Timeline

During recent weeks, I have seen different scams on Facebook attempt to convince users to install Google Chrome extensions. I have noticed some conversations taking place around the scams; people not sure how to get rid of the scammer photos or how to prevent the scams from spreading further. Some users have unfortunately  gone as far as creating new Facebook profiles for themselves. This is not necessary.

If you have been tricked by one of these scams, here is how you can clean up your browser and Facebook timeline:

Remove bad browser extensions

If you have installed the Chrome extension for Facebook Black, Profile Spy ("See Your Profile Viewers"), or Free PS4, you will need to uninstall it from your browser:

  1. Open the Google Chrome browser.
  2. Type chrome://extensions into the browser address bar.
  3. Click the trash can icon to delete bad extensions
  4. Click Remove at the confirmation dialog

The Google Chrome extension page can help you identify any bad extensions that you have installed. In this preceding example you can see both the "Get PS4" and "See Your Profile Viewers" extensions that have been installed.

To delete a bad browser extension, just click the trash can icon and confirm.

Remove unwanted Facebook pages

The preceding Chrome extensions may be responsible for creating Facebook pages using your profile. Now you should confirm whether or not scammer Facebook pages were created in your account and then remove them:

  1. Click the gear icon at the top right corner of your Facebook profile and select the page you wish to modify.
  2. Once the Facebook page has loaded, click Edit Page at the top.
  3. Select Manage Permissions.
  4. Click Permanently delete [NAME OF PAGE] at the bottom.
  5. Click Delete to permanently remove the Facebook page.

As you can see in this preceding example, a randomly created Facebook page was found being used by scammers. You can prevent friends from being photo-tagged with scammer spam by permanently deleting these scammer Facebook pages.

After page deletion you should arrive back at your main Facebook profile.

Remove scammer posts from your Facebook timeline

In order to keep the scam in circulation, the previously mentioned Chrome extensions have downloaded JavaScript files. These files were responsible for performing scammer activity, including tagging your friends in photos to promote the scam in news feeds.

The last step is to remove the photos the scam extension has posted on your behalf and get a clean Facebook timeline:

  1. Go to your profile timeline.
  2. Scroll through your timeline to check for photos published by the scam.
  3. Hover over the timeline story item and click the pencil icon.
  4. Select Delete Photo.

Deleting the photos left by scammers on your timeline helps stop promotion of the scam.

However, in another scenario, you may be the one who is tagged by a scammer photo in a timeline. In that case, you should report the scam to Facebook:

  1. Hover over the timeline story item and click the pencil icon.
  2. Select Report/Remove Tag.
  3. Check I want to untag myself and I want this photo removed from Facebook and select It’s spam.
  4. Click Continue to confirm.

And now that you have removed bad extensions from your browser, cleaned up your Facebook profile timeline, and reported scammer spam, point your friends to this blog post so that they can clean up their own browsers and Facebook timelines.

Don't forget to stay vigilant

These clean-up instructions will help you remove scams circulating on Facebook that involve Google Chrome extensions. But, as mentioned before, scammers are relentless; they are likely to change their tactics again and again. Proceed with caution on social networks and avoid installing any browser extensions in exchange for free products or special features.

Symantec customers are protected against these types of attacks by our Web Attack: Fake Facebook Application 3 IPS signature.

Social Scams – Part 1: Reusing Old Scams to Push Browser Extensions

Last year, we talked about scams and spam circulating on Facebook in our whitepaper. Social networking scammers often reuse common lures to trick users, such as offering free products or additional features that are not available on their network of choice. What these scammers do differently is find new ways to get more eyeballs to view their specific links. Whether it is likejacking or even convincing users to paste code (an external JavaScript file) into the browser address bar, these scammers are relentless.

Just recently, we published a blog about the Facebook Black scam that has been spreading. While that scam continued to spread, we found two old lures being reused, and also two identical Google Chrome extensions being pushed onto the end user.

"Additional feature" lure

Users of social networks have often requested certain features and wondered whether they would ever be implemented on their favorite sites. One of the most commonly requested features across all social networks has been a way to see who has visited one's profile. This feature has never been available, yet this lure has been used in scams across many of the most popular social networks over the years.


Figure 1. Photo-tagging spam claiming additional feature

In fact, this lure—commonly found on social networks—is identical to the one used in the Facebook Black scam we posted about recently. Users are redirected through an iFrame on a Facebook page and then taken to a website where they are enticed to install a Google Chrome extension.


Figure 2. Browser extension claiming additional feature

Installing the extension does nothing—except present the user with a set of surveys to fill out in order to unlock the additional feature. The feature never gets unlocked. The only thing that happens is the scammers make money off of every survey completed successfully.


Figure 3. Scammer survey

"Get something free" lure

Let’s face it: people like free stuff. But free stuff on social networks is not really free. The newest products are the most valued by users and scammers know this. This is why they continue to reuse this lure.


Figure 4.  Web page claiming to get something free

For instance, in February Sony announced their new video game console, PS4. It is not scheduled to arrive in stores until the year-end holiday season. However, that has not stopped scammers from attempting to trick users by offering a free PS4 test unit that they can keep.


Figure 5. Browser extension claiming to get something free

The Web page for this scam claims that users can get a voucher for a free PS4. In reality, there is no voucher. There is just a browser extension created by scammers.

When users install this browser extension, JavaScript files are downloaded onto the user's computers. These files then perform various actions in the user's Facebook account, like creating a Facebook page with an iFrame and posting a photo the user's friends are subsequently tagged in (see previous Figure 1). And this is how the scam spreads.


Symantec customers are protected against these types of attacks by our Web Attack: Fake Facebook Application 3 IPS signature.

Be cautious when you see offers for free products on social networks, especially products that are highly sought after. Also, if a feature is not currently available on a social network, chances are there is a reason that it is not available. Do not install browser extensions from unverified sources—even if they offer free products or access to an unavailable feature—and be especially suspicious of anything that is promoted aggressively on your social networks.

Google, for their part, removes malicious Chrome extensions as they find them and are improving their automated systems to help them detect items containing malware.

However, in the next post we provide instructions on how to remove these scammer browser extensions yourself, and how to clean up your Facebook timeline from all the spam left by scammers.