macOS 11.3 Patches Security Vulnerability That Bypassed Built-In Malware Protections

Apple today confirmed to TechCrunch that the just-released macOS 11.3 software update patches a security vulnerability that reportedly could have allowed a hacker to remotely access a user's sensitive data by tricking a user into opening a spoofed document.

apple security banner
"All the user would need to do is double click — and no macOS prompts or warnings are generated," said security researcher Cedric Owens, who discovered the vulnerability in mid-March, according to the report. Owens developed a proof-of-concept app masquerading as a harmless document that exploits the bug to launch the Calculator app, but he said the vulnerability could be exploited for more nefarious purposes.

According to security researcher Patrick Wardle, the vulnerability was the result of a logic bug in macOS's underlying code.

"In simple terms, macOS apps aren't a single file but a bundle of different files that the app needs to work, including a property list file that tells the application where the files it depends on are located," explains TechCrunch. "But Owens found that taking out this property file and building the bundle with a particular structure could trick macOS into opening the bundle — and running the code inside — without triggering any warnings."

In addition to fixing the bug in macOS 11.3, Apple told TechCrunch it patched earlier macOS versions to prevent abuse, and updated macOS's built-in anti-malware system XProtect to block malware from exploiting the vulnerability. The report says the bug was exploited for months, but it's unclear how many users were impacted.

Related Forum: macOS Big Sur

Popular Stories

apple store down feature

Here's Why the Apple Store is Going Down

Thursday November 27, 2025 1:01 pm PST by
Apple's online store is going down for a few hours on a rolling country-by-country basis right now, but do not get your hopes up for new products. Apple takes its online store down for a few hours ahead of Black Friday every year to tease/prepare for its annual gift card offer with the purchase of select products. The store already went down and came back online in Australia and New Zealand, ...
iPhone Pocket Short

iPhone Pocket is Now Completely Sold Out Worldwide

Tuesday November 25, 2025 7:16 am PST by
Apple recently teamed up with Japanese fashion brand ISSEY MIYAKE to create the iPhone Pocket, a limited-edition knitted accessory designed to carry an iPhone. However, it is now completely sold out in all countries where it was released. iPhone Pocket became available to order on Apple's online store starting Friday, November 14, in the United States, France, China, Italy, Japan, Singapore, ...
streaming black friday 2025

Best Black Friday Streaming Deals - Save Big on Apple TV, Disney+, Hulu, and More

Thursday November 27, 2025 1:14 pm PST by
We've been focusing on deals on physical products over the past few weeks, but Black Friday is also a great time of year to purchase a streaming membership. Some of the biggest services have great discounts for new and select returning members this week, including Apple TV, Disney+, Hulu, Paramount+, Peacock, and more. Note: MacRumors is an affiliate partner with some of these vendors. When...
New Intel Logo

Apple and Intel Rumored to Partner on Mac Chips Again in a New Way

Friday November 28, 2025 7:33 am PST by
While all Macs are now powered by Apple's custom-designed chips, a new rumor claims that Apple may rekindle its partnership with Intel, albeit in a new and limited way. Apple supply chain analyst Ming-Chi Kuo today said Intel is expected to begin shipping Apple's lowest-end M-series chip as early as mid-2027. Kuo said Apple plans to utilize Intel's 18A process, which is the "earliest...
Apple Foldable Thumb

Foldable iPhone to Debut These Three Breakthrough Features

Tuesday November 25, 2025 7:09 am PST by
Apple's first foldable iPhone is expected to launch alongside the iPhone 18 Pro models in fall 2026, and it's shaping up to include three standout features that could set it apart from the competition. The book-style foldable will reportedly feature an industry-first 24-megapixel under-display camera built into the inner display, according to a recent JP Morgan equity research report. That...
iphone air camera

iPhone Air Flop Sparks Industry Retreat From Ultra-Thin Phones

Thursday November 27, 2025 3:14 am PST by
Apple's disappointing iPhone Air sales are causing major Chinese mobile vendors to scrap or freeze their own ultra-thin phone projects, according to reports coming out of Asia. Since the ‌iPhone Air‌ launched in September, there have been reports of poor sales and manufacturing cuts, while Apple's supply chain has scaled back shipments and production. Apple supplier Foxconn has...
streaming black friday 2025

Black Friday Streaming Deals Include Big Savings on Disney+, Hulu, Apple TV, and More

Monday November 24, 2025 8:03 am PST by
We've been focusing on deals on physical products over the past few weeks, but Black Friday is also a great time of year to purchase a streaming membership. Some of the biggest services have great discounts for new and select returning members this week, including Disney+, Hulu, Paramount+, Peacock, and more. Note: MacRumors is an affiliate partner with some of these vendors. When you click a...
iphone black friday gold

The Best Black Friday iPhone Deals Still Available

Friday November 28, 2025 6:24 am PST by
Cellular carriers have always offered big savings on the newest iPhone models during the holidays, and Black Friday 2025 sales have kicked off at AT&T, Verizon, T-Mobile, and more. Right now we're tracking notable offers on the iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max, and iPhone Air. For even more savings, keep an eye on older models during the holiday shopping season. Note: MacRumors is...

Top Rated Comments

LV426 Avatar
60 months ago

Apple is definitely protecting the consumers.
Well, Apple definitely wasn’t protecting customers when they introduced this vulnerability.

There‘s a good write up of the disastrous security flaw here ('https://objective-see.com/blog/blog_0x64.html').
Score: 3 Votes (Like | Disagree)
TheYayAreaLiving ?️ Avatar
60 months ago
Apple is definitely protecting the consumers.
Score: 3 Votes (Like | Disagree)
Ethosik Avatar
60 months ago

This is why the Mac App Store should remain closed, walled and protected... oh, wait...
And the solution is to......remove the store and protected systems in place? There will always be bad things that slip through. The only....ONLY way to achieve 100% secure system is if the Apple App Review process takes months. Have Apple developers look through your code and REALLY test it. But would developers like this?

There are still murders, robberies, other criminal acts. Does that mean the police does nothing?
Score: 3 Votes (Like | Disagree)
RedTheReader Avatar
60 months ago

In simple terms, macOS apps aren't a single file but a bundle of different files that the app needs to work,
Everything Is a File™
Score: 2 Votes (Like | Disagree)
MauiPa Avatar
60 months ago
"The report says the bug was exploited for months, but it's unclear how many users were impacted." What report? A report is not mentioned in the article.
Score: 2 Votes (Like | Disagree)
lkrupp Avatar
60 months ago
Security updates for Mojave and Catalina out now that patch the same security issues.
Score: 2 Votes (Like | Disagree)