Entries Tagged "browsers"

Page 1 of 6

Identifying People by Their Browsing Histories

Interesting paper: “Replication: Why We Still Can’t Browse in Peace: On the Uniqueness and Reidentifiability of Web Browsing Histories”:

We examine the threat to individuals’ privacy based on the feasibility of reidentifying users through distinctive profiles of their browsing history visible to websites and third parties. This work replicates and extends the 2012 paper Why Johnny Can’t Browse in Peace: On the Uniqueness of Web Browsing History Patterns[48]. The original work demonstrated that browsing profiles are highly distinctive and stable. We reproduce those results and extend the original work to detail the privacy risk posed by the aggregation of browsing histories. Our dataset consists of two weeks of browsing data from ~52,000 Firefox users. Our work replicates the original paper’s core findings by identifying 48,919 distinct browsing profiles, of which 99% are unique. High uniqueness hold seven when histories are truncated to just 100 top sites. We then find that for users who visited 50 or more distinct domains in the two-week data collection period, ~50% can be reidentified using the top 10k sites. Reidentifiability rose to over 80% for users that browsed 150 or more distinct domains. Finally, we observe numerous third parties pervasive enough to gather web histories sufficient to leverage browsing history as an identifier.

One of the authors of the original study comments on the replication.

Posted on August 25, 2020 at 6:28 AMView Comments

Firefox Enables DNS over HTTPS

This is good news:

Whenever you visit a website — even if it’s HTTPS enabled — the DNS query that converts the web address into an IP address that computers can read is usually unencrypted. DNS-over-HTTPS, or DoH, encrypts the request so that it can’t be intercepted or hijacked in order to send a user to a malicious site.

[…]

But the move is not without controversy. Last year, an internet industry group branded Mozilla an “internet villain” for pressing ahead the security feature. The trade group claimed it would make it harder to spot terrorist materials and child abuse imagery. But even some in the security community are split, amid warnings that it could make incident response and malware detection more difficult.

The move to enable DoH by default will no doubt face resistance, but browser makers have argued it’s not a technology that browser makers have shied away from. Firefox became the first browser to implement DoH — with others, like Chrome, Edge, and Opera — quickly following suit.

I think DoH is a great idea, and long overdue.

Slashdot thread. Tech details here. And here’s a good summary of the criticisms.

Posted on February 25, 2020 at 9:15 AMView Comments

New Ways to Track Internet Browsing

Interesting research on web tracking: “Who Left Open the Cookie Jar? A Comprehensive Evaluation of Third-Party Cookie Policies:

Abstract: Nowadays, cookies are the most prominent mechanism to identify and authenticate users on the Internet. Although protected by the Same Origin Policy, popular browsers include cookies in all requests, even when these are cross-site. Unfortunately, these third-party cookies enable both cross-site attacks and third-party tracking. As a response to these nefarious consequences, various countermeasures have been developed in the form of browser extensions or even protection mechanisms that are built directly into the browser.

In this paper, we evaluate the effectiveness of these defense mechanisms by leveraging a framework that automatically evaluates the enforcement of the policies imposed to third-party requests. By applying our framework, which generates a comprehensive set of test cases covering various web mechanisms, we identify several flaws in the policy implementations of the 7 browsers and 46 browser extensions that were evaluated. We find that even built-in protection mechanisms can be circumvented by multiple novel techniques we discover. Based on these results, we argue that our proposed framework is a much-needed tool to detect bypasses and evaluate solutions to the exposed leaks. Finally, we analyze the origin of the identified bypass techniques, and find that these are due to a variety of implementation, configuration and design flaws.

The researchers discovered many new tracking techniques that work despite all existing anonymous browsing tools. These have not yet been seen in the wild, but that will change soon.

Three news articles. BoingBoing post.

Posted on August 17, 2018 at 5:26 AMView Comments

Google Discloses Details of an Unpatched Microsoft Vulnerability

Google’s Project Zero is serious about releasing the details of security vulnerabilities 90 days after they alert the vendors, even if they’re unpatched. It just exposed a nasty vulnerability in Microsoft’s browsers.

This is the second unpatched Microsoft vulnerability it exposed last week.

I’m a big fan of responsible disclosure. The threat to publish vulnerabilities is what puts pressure on vendors to patch their systems. But I wonder what competitive pressure is on the Google team to find embarrassing vulnerabilities in competitors’ products.

Posted on March 9, 2017 at 6:28 AMView Comments

Firefox Removing Battery Status API

Firefox is removing the battery status API, citing privacy concerns. Here’s the paper that described those concerns:

Abstract. We highlight privacy risks associated with the HTML5 Battery Status API. We put special focus on its implementation in the Firefox browser. Our study shows that websites can discover the capacity of users’ batteries by exploiting the high precision readouts provided by Firefox on Linux. The capacity of the battery, as well as its level, expose a fingerprintable surface that can be used to track web users in short time intervals. Our analysis shows that the risk is much higher for old or used batteries with reduced capacities, as the battery capacity may potentially serve as a tracking identifier. The fingerprintable surface of the API could be drastically reduced without any loss in the API’s functionality by reducing the precision of the readings. We propose minor modifications to Battery Status API and its implementation in the Firefox browser to address the privacy issues presented in the study. Our bug report for Firefox was accepted and a fix is deployed.

W3C is updating the spec. Here’s a battery tracker found in the wild.

Posted on November 7, 2016 at 12:59 PMView Comments

Detecting QUANTUMINSERT

Fox-IT has a blog post (and has published Snort rules) on how to detect man-on-the-side Internet attacks like the NSA’s QUANTUMINSERT.

From a Wired article:

But hidden within another document leaked by Snowden was a slide that provided a few hints about detecting Quantum Insert attacks, which prompted the Fox-IT researchers to test a method that ultimately proved to be successful. They set up a controlled environment and launched a number of Quantum Insert attacks against their own machines to analyze the packets and devise a detection method.

According to the Snowden document, the secret lies in analyzing the first content-carrying packets that come back to a browser in response to its GET request. One of the packets will contain content for the rogue page; the other will be content for the legitimate site sent from a legitimate server. Both packets, however, will have the same sequence number. That, it turns out, is a dead giveaway.

Here’s why: When your browser sends a GET request to pull up a web page, it sends out a packet containing a variety of information, including the source and destination IP address of the browser as well as so-called sequence and acknowledge numbers, or ACK numbers. The responding server sends back a response in the form of a series of packets, each with the same ACK number as well as a sequential number so that the series of packets can be reconstructed by the browser as each packet arrives to render the web page.

But when the NSA or another attacker launches a Quantum Insert attack, the victim’s machine receives duplicate TCP packets with the same sequence number but with a different payload. “The first TCP packet will be the ‘inserted’ one while the other is from the real server, but will be ignored by the [browser],” the researchers note in their blog post. “Of course it could also be the other way around; if the QI failed because it lost the race with the real server response.”

Although it’s possible that in some cases a browser will receive two packets with the same sequence number from a legitimate server, they will still contain the same general content; a Quantum Insert packet, however, will have content with significant differences.

It’s important we develop defenses against these attacks, because everyone is using them.

EDITED TO ADD (5/14): Detection for QI was recently released for Bro, Snort and Suricata.

Posted on May 4, 2015 at 6:17 AMView Comments

Adware Vendors Buy and Abuse Chrome Extensions

This is not a good development:

To make matters worse, ownership of a Chrome extension can be transferred to another party, and users are never informed when an ownership change happens. Malware and adware vendors have caught wind of this and have started showing up at the doors of extension authors, looking to buy their extensions. Once the deal is done and the ownership of the extension is transferred, the new owners can issue an ad-filled update over Chrome’s update service, which sends the adware out to every user of that extension.

[…]

When malicious apps don’t follow Google’s disclosure policy, diagnosing something like this is extremely difficult. When Tweet This Page started spewing ads and malware into my browser, the only initial sign was that ads on the Internet had suddenly become much more intrusive, and many auto-played sound. The extension only started injecting ads a few days after it was installed in an attempt to make it more difficult to detect. After a while, Google search became useless, because every link would redirect to some other webpage. My initial thought was to take an inventory of every program I had installed recently — I never suspected an update would bring in malware. I ran a ton of malware/virus scanners, and they all found nothing. I was only clued into the fact that Chrome was the culprit because the same thing started happening on my Chromebook — if I didn’t notice that, the next step would have probably been a full wipe of my computer.

Posted on January 21, 2014 at 6:33 AMView Comments

The Onion on Browser Security

Wise advice:

At Chase Bank, we recognize the value of online banking­ — it’s quick, convenient, and available any time you need it. Unfortunately, though, the threats posed by malware and identity theft are very real and all too common nowadays. That’s why, when you’re finished with your online banking session, we recommend three simple steps to protect your personal information: log out of your account, close your web browser, and then charter a seafaring vessel to take you 30 miles out into the open ocean and throw your computer overboard.

And while we’re talking about the Onion, they were recently hacked by Syria (either the government or someone on their side). They responded in their own way.

EDITED TO ADD (5/11): How The Onion got hacked.

Posted on May 10, 2013 at 1:49 PMView Comments

1 2 3 6

Sidebar photo of Bruce Schneier by Joe MacInnis.