firefoxlogoMozilla has announced a new security tool for users of its Firefox web browser. Called Firefox Monitor, the website lets visitors check if their accounts have been included in known data breaches and the types of data exposed in each breach.

The security tool is the result of a partnership between Mozilla and HaveIBeenPwned.com (HIBP), a site set up by security researcher Troy Hunt that includes a database of email addresses that are known to have been compromised in data breaches.

Thanks to the partnership, Firefox is able to check email addresses against the HIBP database via a method of anonymized data sharing (full details can be found in Troy Hunt's blog post). The new tool builds on Firefox's existing HIBP integration, which tells users if a site they are visiting was previously exposed in a data breach.

Firefox Monitor Homepage2
In February, password management app 1Password announced its own partnership with HIBP, which lets users check that their passwords haven't been leaked online. Since that time, developers AgileBits have built the Pwned Passwords database list into its 1Password desktop apps. As of today, users can also search HIBP from directly within 1Password via the Watchtower feature in the web version of the product.

Mozilla says it will begin trialling the new integration between HIBP and Firefox to make breach data searchable over the coming weeks.

Firefox Quantum is available for macOS as a free download directly from the Mozilla website.

Top Rated Comments

bLackjackj Avatar
98 months ago
If they are creating a hash of my email it can be reversed engineered back to my email. No thanks.
No it can't,..I don't know where you are making up this information from, but it's wrong.
Score: 4 Votes (Like | Disagree)
mrzz Avatar
98 months ago
I used to like the old pre-Firefox, “Mozilla” browser. Remember that?
I'm fine with speed improvements in FF58+ I
If they are creating a hash of my email it can be reversed engineered back to my email. No thanks.
I recommend you to read something about hashes.
Score: 4 Votes (Like | Disagree)
woodlandtrek Avatar
98 months ago
If they are creating a hash of my email it can be reversed engineered back to my email. No thanks.
Firefox will not only hash your email with SHA-1, it will send only the first 6 characters of that hash to HIBP. That amount of data is useless to try to recreate your email.
Score: 1 Votes (Like | Disagree)
mikes63737 Avatar
98 months ago
Your e-mail could be brute-forced from the hash -- but it cannot be reversed.

Eg, the service could say "I have a hash abf112bacd3489... is this hash equal to a@gmail.com? No? How about b@gmail.com? No?"

However, nobody... NOBODY is going to take the time to brute-force each individual email/hash. It would take way too much time and effort.
Score: 1 Votes (Like | Disagree)
JosephAW Avatar
98 months ago
I'm assuming you can opt out of this "feature" where they send your email to this third party?
Score: 1 Votes (Like | Disagree)
tothsa Avatar
98 months ago
I'm assuming you can opt out of this "feature" where they send your email to this third party?
Did you read the full article? It says Mozilla uses “anonymized data sharing” so your email address won’t be revealed to third parties!
Score: 1 Votes (Like | Disagree)

Popular Stories

top stories 2025 12 20

Top Stories: iOS 26.3 Beta, Major Apple Leaks, and More

Saturday December 20, 2025 6:00 am PST by
You'd think things would be slowing down heading into the holidays, but this week saw a whirlwind of Apple leaks and rumors while Apple started its next cycle of betas following last week's release of iOS 26.2 and related updates. This week also saw the release of a new Apple Music integration with ChatGPT, so read on below for all the details on this week's biggest stories! Top Stories i...
maxresdefault

Where's the New Apple TV?

Monday December 22, 2025 11:30 am PST by
Apple hasn't updated the Apple TV 4K since 2022, and 2025 was supposed to be the year that we got a refresh. There were rumors suggesting Apple would release the new Apple TV before the end of 2025, but it looks like that's not going to happen now. Subscribe to the MacRumors YouTube channel for more videos. Bloomberg's Mark Gurman said several times across 2024 and 2025 that Apple would...
iPhone Top Left Hole Punch Face ID Feature Purple

iPhone 18 Pro Features Leaked in New Report, Including Under-Screen Face ID

Tuesday December 16, 2025 8:44 am PST by
Next year's iPhone 18 Pro and iPhone 18 Pro Max will be equipped with under-screen Face ID, and the front camera will be moved to the top-left corner of the screen, according to a new report from The Information's Wayne Ma and Qianer Liu. As a result of these changes, the report said the iPhone 18 Pro models will not have a pill-shaped Dynamic Island cutout at the top of the screen....
ios 18 security update

Don't Want to Upgrade to iOS 26? Here's How to Stay on iOS 18 [Update: Now Unavailable]

Friday December 19, 2025 10:37 am PST by
Since the beginning of December, Apple has been pushing iPhone users who opted to stay on iOS 18 to install iOS 26 instead. Apple started by making the iOS 18 upgrades less visible, and has now transitioned to making new iOS 18 updates unavailable on any device capable of running iOS 26. If you have an iPhone 11 or later, Apple is no longer offering new versions of iOS 18, even though there...
apple beta 26 lineup

Apple's 2026 and 2027 Product Roadmap: Foldable iPhone, iPhone 18 Pro, M5 Macs, and More

Tuesday December 16, 2025 4:42 pm PST by
There has been a whirlwind of rumors over the last few days, sourced from leaked internal software designed for the iPhone and the Mac, and news sites like The Information. Below, we have a quick recap of everything we've heard this week, which serves as a guide to Apple's product plans in 2026 and beyond. We've organized the info by likely release date, though there are some products that...
iPhone Chips

Apple Clings to Samsung as RAM Prices Soar

Monday December 22, 2025 6:17 am PST by
Apple is significantly increasing its reliance on Samsung for iPhone memory as component prices surge, according to The Korea Economic Daily. Apple is said to be expanding the share of iPhone memory it sources from Samsung due to rapidly rising memory prices. The shift is expected to result in Samsung supplying roughly 60% to 70% of the low-power DRAM used in the iPhone 17, compared with a...
generic tracking prompt orange

Apple Hit With Supersized Fine in Italy Over an iPhone Privacy Feature

Monday December 22, 2025 7:47 am PST by
Italy's Competition Authority (AGCM) has imposed a €98.6 million ($116 million) fine on Apple over its App Tracking Transparency feature. Since the release of iOS 14.5 in April 2021, Apple has required apps to ask for permission before tracking a user's activity across other apps and websites for personalized advertising, as part of a feature named App Tracking Transparency. If a user...