Mozilla Firefox: New defenses to combat fingerprinting

Mozilla is announcing its most ambitious effort yet to enhance user anonymity online and protect against digital fingerprinting . With the release of Firefox 145 , the company is introducing an upgraded set of privacy measures that further reduce websites’ ability to engage in fingerprinting digital — one of the most sophisticated forms of online tracking.

What's new in Firefox 145

The new protections will initially be enabled in Private Browsing Mode and Enhanced Tracking Protection (ETP) Strict mode, before gradually becoming the default across all browser installations. Mozilla plans to evaluate website behavior and optimize the system before fully enabling it to avoid functionality issues.

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Digital identification through “fingerprinting” is based on distinctive system characteristics, such as operating system, screen resolution, graphics card, fonts, and time zone. By combining this data, websites can create a unique profile for each user, capable of recognizing them even without cookies or login.

Protection: From "Phase 1" to "Phase 2"

Mozilla has already taken steps in this direction in recent years. Since 2021, the development team has been implementing measures to limit the most common fingerprinting techniques. The so-called Phase 1 Protections had reduced the probability of identifying a user to about 35%, compared to 65% without any protection.

With the new Phase 2, the system becomes even more “invisible.” Firefox now blocks requests that attempt to reveal details about the device’s hardware, the number of processor cores, multi-touch support, or the dimensions of the taskbar.

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Mozilla: How new defense techniques against fingerprinting work

Mozilla implements a series of smart interventions to reduce the footprint left by users without disrupting the browsing experience:

• Introduction of “noise” in background images: small, invisible changes prevent pixel resolution that could be used for identification.

• Font restriction: the program displays only the basic fonts of the operating system, excluding locally installed ones, except for those required for specific languages ​​such as Japanese, Chinese or Arabic.

• Limited feature reporting: Firefox "declares" to sites that the device has two CPU cores and a standard screen resolution, regardless of the actual features.

• Touch support is listed as 0, 1, or 5.

Thanks to these techniques, Mozilla estimates that only 20% of users remain potentially traceable — a significant improvement over previous versions.

The balance between privacy and functionality

While Mozilla could theoretically tighten defenses even further, it points out that excessive data hiding would lead to usability issues. Many web applications need access to system resources for legitimate functions, such as interface customization or graphics optimization.

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For this reason, users experiencing malfunctions can exclude specific websites from the protection system, maintaining control over their experience.

The release of Firefox 145 and the end of an era

Firefox 145 is available today. Importantly, this release also marks the end of support for 32-bit Linux, a decision driven by reduced demand and increased maintenance costs.

Mozilla's message: "Privacy as a fundamental right"

With the new update, Mozilla reinforces its reputation as one of the last companies to actively defend the right to digital anonymity. In an era where surveillance has become the norm rather than the exception, Firefox 145 is a reminder that technology can—and should—serve the user, not expose them.

Source: www.bleepingcomputer.com