Apple Updates OS X Anti-Malware Definitions to Block 'Yontoo' Adware

Yesterday, word surfaced of new malware targeting major browsers on the Mac platform with adware capable of injecting advertising into users' browsing experiences. The malware, known as "Yontoo", masquerades as a video plug-in or download accelerator in order to trick users into installing the package.

yontoo_xprotect
As noted by security firm Intego, Apple has already updated its "Xprotect" anti-malware system to recognize Yontoo and warn users who attempt to install it on their machines.

Apple has decided the Yontoo Adware has fallen too far on the side of undesirable behavior, as they have released an update to the XProtect.plist definitions file to provide Mac OS X with basic detection for the Yontoo adware as OSX.AdPlugin.i. In testing, it appears this detection is very specific and potentially location-dependent. This extra specificity is likely there so as to catch only the surreptitious installations of this file.

Apple routinely uses its Xprotect anti-malware tools introduced in OS X Snow Leopard to provide rudimentary protection against threats, and has expanded its efforts in OS X Mountain Lion with the introduction of Gatekeeper to allow users to restrict app installation to software from identified developers registered with Apple, or even to only apps installed through the Mac App Store.

Apple has also been using Xprotect to enforce minimum version requirements for plug-ins such as Java and Flash Player, forcing users to upgrade from earlier versions known to have significant security issues.

Popular Stories

iPhone 17 Pro Blue Feature Tighter Crop

iPhone 17 Pro Launching in Three Months With These 12 New Features

Saturday June 21, 2025 2:45 pm PDT by
The iPhone 17 Pro and iPhone 17 Pro Max are around three months away, and there are plenty of rumors about the devices from credible sources. Below, we recap key changes rumored for the iPhone 17 Pro models as of June 2025:Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone X...
iPhone 16 Battery Life Feature

iOS 26's New Battery Life Mode Available Only on These iPhone Models

Saturday June 21, 2025 9:02 am PDT by
Last week, we reported that iOS 26 introduces an opt-in Adaptive Power Mode on the iPhone, alongside the existing Low Power Mode. Apple says that Adaptive Power Mode can make "small performance adjustments" when necessary to extend an iPhone's battery life, including slightly lowering the display brightness or allowing some activities to "take a little longer." The full description of...
All Screen iPhone 2027 Feature 1

iPhone Reportedly Moving to All-Screen Design in Two Stages

Sunday June 22, 2025 3:58 pm PDT by
Apple has long been working towards an iPhone with an all-screen design, and it might finally achieve the feat in a few more years from now. In his Power On newsletter today, Bloomberg's Mark Gurman said that Apple will shrink the size of the Dynamic Island on new iPhone models released next year. A year after that, he expects Apple to release a redesigned 20th-anniversary iPhone model....
iPhone 17 Pro Blue Feature Tighter Crop

iPhone 17 Pro's Alleged Vapor Chamber Cooling System Partly Revealed

Sunday June 22, 2025 6:37 am PDT by
Apple's upcoming iPhone 17 Pro and iPhone 17 Pro Max models are rumored to be equipped with a vapor chamber cooling system, and a leaker known as Majin Bu today shared a photo of an alleged copper thermal plate for the system. Many high-end Android smartphones like Samsung's Galaxy S25 Ultra are equipped with a vapor chamber cooling system, which can manage heat dissipation inside the...
Wi Fi WiFi General Feature

iOS 26 Adding Two New Wi-Fi Features, Allows AirDrop and AirPlay Alternatives

Saturday June 21, 2025 7:02 am PDT by
iOS 26 is gaining two new Wi-Fi features, including Captive Assist and Wi-Fi Aware. MacRumors contributor Aaron Perris discovered a reference to Captive Assist within the code for the first iOS 26 developer beta, but Apple has yet to enable the feature. It should be available by the time the software update is released later this year. In his Power On newsletter last month, Bloomberg's...
ios 26 control center b2

iOS 26 Beta 2 Fixes Control Center Design

Monday June 23, 2025 10:58 am PDT by
With the second beta of iOS 26 that Apple provided to developers today, Apple addressed one of the major complaints that people have had with Liquid Glass. iOS 26 beta 1 on left, iOS 26 beta 2 on right The Control Center buttons are now slightly more opaque, making it easier to see the different control options even on a multicolored background. The new, more opaque look is apparent with the ...
iOS 26 on Three iPhones

iOS 26 Includes These Five Smaller Features You Might Have Missed

Saturday June 21, 2025 11:18 am PDT by
While the dust is beginning to settle on the first iOS 26 beta, we continue to take a closer look at new features coming with the update. Below, we recap five smaller changes that you might have missed. Emoji Game Apple News+ subscribers in the U.S. and Canada can play a new Emoji Game, which tasks players with completing words and phrases with emoji. This is the fifth game that is...
airpods 4 blue

Apple Offering Free AirPods — Here's How to Get Them

Tuesday June 17, 2025 6:33 am PDT by
Apple is running a new promotion that offers free AirPods to qualifying customers. Now through September 30, college and university students in the U.S., Canada, Mexico, and Singapore can receive free AirPods 4 when they purchase an eligible new Mac or iPad from Apple. AirPods Pro 2 are also available at a discount. If you do not want AirPods, the promotion also offers various other...
iPhone 17 Pro Blue Feature Tighter Crop

iPhone 17 Pro Launching in Three Months With These 12 New Features

Saturday June 14, 2025 5:45 pm PDT by
The iPhone 17 Pro and iPhone 17 Pro Max are three months away, and there are plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models as of June 2025:Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone X through iPhone 14 Pro have a...

Top Rated Comments

anzio Avatar
160 months ago
Great news. Though I've said it before, all software must pass through my built-in antivirus called "common sense." It's updated frequently.

So I'm not too worried.
Score: 18 Votes (Like | Disagree)
camnchar Avatar
160 months ago
But what about my freedom to install adware!
Score: 10 Votes (Like | Disagree)
madsci954 Avatar
160 months ago
But what about my freedom to install adware!

Said no one ever.
Score: 7 Votes (Like | Disagree)
tevion5 Avatar
160 months ago
But what about my freedom to install adware!

Such freedoms should come with free laxative overdoses.
Score: 6 Votes (Like | Disagree)
Mr Fusion Avatar
160 months ago
But what about my freedom to install adware!
You joke now...

... Just wait till OS XI debuts and you'll have to wait for the jailbreak to install third-party apps. ;)
Score: 5 Votes (Like | Disagree)
HenryDJP Avatar
160 months ago
This is a very good thing, not trying to be critical.

But isn't this a slippery slope towards 'microsoft security essentials'? For now xprotect surely uses less system resources, but I'd wager that eventually the day will come for antivirus/antimalware on osx.

Shouldn't matter much to you since you're running Windows 7...
Score: 4 Votes (Like | Disagree)