[German]Brief information for blog readers who are still running Windows 7 SP1 and use Firefox as browser. In a few weeks, the change to version 100.x is due, and in order to install the browser then, it is mandatory to have the Windows 7 update KB4474419 installed. Here's a brief overview of why this is required.
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I already caught the topic last week from Martin Brinkmann on ghack.net via the following tweet. But also techdows mentioned it here already on March 30, 2022.das Ganze bereits vorige Woche bei Martin Brinkmann auf über nachfolgenden Tweet mitbekommen.
Currently it affects only people who want to install the nightly builds of the browser, which also still supports Windows 7 SP1, on an unpatched Windows 7 operating system. According to this page, the release of Firefox 100 is scheduled for May 3, 2022 – so there is still some time.
Why is KB4474419 required?
The technical background why the Windows 7 update KB4474419 is required for the Firefox 100 installation is quite simple. The Mozilla developers will sign the installer package with SHA-256 starting in this release.
Beginning in this release, the Firefox installer for Windows is signed with a SHA-256 digest, rather than SHA-1. Update KB4474419 is required for successful installation on a computer running the Microsoft Windows 7 operating system.
Mozilla noted this in the release notes of version 100.0a, from which the above quote was extracted.
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Why might KB4474419 be missing?
Windows 7 SP1 originally came with support for SHA-1 signing only. Then in 2019, support for SHA-256 was retrofitted (see this support article). Meanwhile, Windows 7 SP1 regularly went out of support from Microsoft on January 14, 2020. Only companies that have booked ESU support will still get security updates (and users who work with corresponding tricks).
So if you are still using Windows 7 SP1 without SHA-2 support and Firefox, you have to install the update KB4474419. However, this should only affect very few users, I guess.
Firefox 100 is not the only app out there that requires the Win7 KB4474419 update, guenni
Malwarebytes requires KB4474419 on Win7 as well (or no program nor software updates will be available):
https://forums.malwarebytes.com/topic/273172-a-missing-security-update-is-required-to-update-mb-what-still-updates/
https://forums.malwarebytes.com/topic/276893-malwarebytes-latest-version-requires-a-windows-update/
even nVidia drivers require it as well:
https://nvidia.custhelp.com/app/answers/detail/a_id/5002/~/driver-installation-issues-on-windows-7
and even Norton on Win7:
https://support.norton.com/sp/en/us/home/current/solutions/v138306812
Firefox version 100 officially released May 3, 2022 and as noted on their release notes page for v100:
https://www.mozilla.org/en-US/firefox/100.0/releasenotes/
"Beginning in this release, the Firefox installer for Windows is signed with a SHA-256 digest, rather than SHA-1. Update KB4474419 is required for successful installation on a computer running Microsoft Windows 7. For more details about this update, visit the Microsoft Technical Support website."