New 'Yontoo' Adware Trojan Targets Major Browsers on OS X

Russian security firm Doctor Web this week highlighted a new trojan (via The Next Web) affecting OS X systems and which installs an adware plug-in capable of injecting ads into users' browsing experience.

As with other trojans, this new Yontoo malware relies on tricking users into installing the package, which in this case masquerades as a movie trailer video plug-in, download accelerator, or other software a user might believe they want or need on their system.

When launched, Trojan.Yontoo.1 displays a dialogue window that asks the user if they want to install Free Twit Tube.

However, after the user presses ‘Continue’, instead of the promised program, the Trojan downloads (from the Internet) and installs the plugin Yontoo for Safari, Chrome and Firefox. These browsers are most popular among Mac OS X users. While a user surfs the web, the plugin transmits information about the loaded pages to a remote server.

In return, it gets a file that enables the Trojan to embed third-party code into pages visited by the user.

As an example of Yontoo's capabilities, Doctor Web shows how ads can be injected into apple.com once the plug-in has been unwittingly installed by the user.

apple_com_adware
Compared to Windows, OS X has long been a relatively unpopular target for malware authors, but attacks targeting Apple customers have been on the rise. Many of the most highly publicized attacks come via trojans that rely on tricking users into granting installation privileges, while third-party platforms such as Java have also frequently been used to inject code into Mac systems.

Apple has been increasing its efforts to fight malware, introducing a rudimentary anti-malware functionality in OS X Snow Leopard and an enhanced Gatekeeper system in OS X Mountain Lion. Apple has also increasingly been blocking vulnerable versions of Java until Oracle is able to release patched versions of its plug-ins.

Popular Stories

Generic iOS 19 Feature Mock Light

iOS 19 Leak Reveals All-New Design

Friday January 17, 2025 2:42 pm PST by
iOS 19 is still around six months away from being announced, but a new leak has allegedly revealed a completely redesigned Camera app. Based on footage it obtained, YouTube channel Front Page Tech shared a video showing what the new Camera app will apparently look like, with the key change being translucent menus for camera controls. Overall, the design of these menus looks similar to...
iPhone 17 Air Size Feature

'iPhone 17 Air' With Rear Camera Bar Allegedly Shown in Leaked Photo

Tuesday January 21, 2025 12:46 pm PST by
A leaker known as "Majin Bu" today shared an alleged image of a component for the rumored, ultra-thin "iPhone 17 Air" model. The blurry, pixelated image shows a pair of rear iPhone shells with a pill-shaped, raised camera bar along the top. On the left side of the bar, there is a circular cutout that appears to be for a single rear camera. On the right side of the bar, there appears to be an ...
2024 App Store Awards

Apple Explains Why It Removed TikTok From the App Store in the U.S.

Sunday January 19, 2025 6:58 am PST by
Apple on late Saturday removed TikTok from the App Store in the U.S., and it has now explained why it was required to take this action. Last year, the U.S. passed a law that required Chinese company ByteDance to divest its ownership of TikTok due to potential national security risks, or else the platform would be banned. That law went into effect today, and companies like Apple and Google...
iPhone SE Dynamic Island Majin Bu

iPhone SE 4 Leak Shows Dynamic Island, Casts Doubt on Rumored 'iPhone 16E' Name

Monday January 20, 2025 9:01 am PST by
A new iPhone SE is widely rumored to launch this year, and the device has potentially been confirmed today by known leaker Evan Blass. In a private social media post, Blass shared an image of what appears to be source code mentioning an iPhone SE (4th Gen), which casts doubt on the alternative "iPhone 16E" name rumored for the device. However, the name in the source code could be a...
airtag 4 pack blue

AirTag 2 Launching This Year With These 3 New Features

Sunday January 19, 2025 8:11 am PST by
After a four-year wait, a new AirTag is finally expected to launch in 2025. Below, we recap rumored upgrades for the accessory. A few months ago, Bloomberg's Mark Gurman said Apple was aiming to release the AirTag 2 around the middle of 2025. While he did not offer a more specific timeframe, that means the AirTag 2 could be announced by the end of June. The original AirTag was announced...
iOS 19 Roundup Feature

iOS 19 Rumored to Be Compatible With These iPhones

Saturday January 18, 2025 10:28 am PST by
iOS 19 will not drop support for any iPhone models, according to French website iPhoneSoft.fr. The report cited a source who said iOS 19 will be compatible with any iPhone that can run iOS 18, which would mean the following models: iPhone 16 iPhone 16 Plus iPhone 16 Pro iPhone 16 Pro Max iPhone 15 iPhone 15 Plus iPhone 15 Pro iPhone 15 Pro Max iPhone 14 iPhon...
iOS 18

Here Are Apple's Full Release Notes for iOS 18.3

Tuesday January 21, 2025 4:31 pm PST by
Apple provided developers and public beta testers with the release candidate version of iOS 18.3 today, and with it comes release notes confirming what's new. While we knew about several of the features that are in the update, there are some lesser known tweaks and bug fixes. The update adds new Visual Intelligence features for iPhone 16 models, it tweaks Notification summaries on all...
ipad pro 2024

New iPad Pro Reportedly Launching This Year

Tuesday January 21, 2025 6:40 am PST by
Apple plans to release at least one new iPad Pro model this year, according to a supplier-focused report today from Korean website The Elec. It is likely that the 11-inch and 13-inch iPad Pro models would be updated simultaneously. After receiving an OLED display last year, the report said the iPad Pro will receive only "minor" changes this year. Overall, the next iPad Pro is expected to...
apple power beats pro 2

Powerbeats Pro 2 Coming Soon: Apple to Announce Them 'Imminently'

Sunday January 19, 2025 8:25 am PST by
In September, Apple said that it would be launching Powerbeats Pro 2 in 2025, and it appears the wireless earbuds are coming very soon. Powerbeats Pro 2 images found in iOS 18 code In his Power On newsletter today, Bloomberg's Mark Gurman said the Powerbeats Pro 2 are "due imminently." In addition to Apple filing the Powerbeats Pro 2 in regulatory databases last month, Gurman said Apple is...

Top Rated Comments

Slix Avatar
155 months ago
Want to install Free Twit Tube?

Seems legit. :rolleyes:
Score: 20 Votes (Like | Disagree)
litmag01 Avatar
155 months ago
Say YES to everything unless it asks to continue.

In that case, press CONTINUE and enter bank account number, routing number and any pertinant passwords.
Score: 18 Votes (Like | Disagree)
anzio Avatar
155 months ago
It's times like this that I'm glad that OS X has XProtect.

Oh yeah. And I'm happy I also wield common sense. :)
Score: 14 Votes (Like | Disagree)
Pechente Avatar
155 months ago
Wow, a user can be tricked to actively install harmful software - a serious flaw in OS X!
Score: 11 Votes (Like | Disagree)
Apple_Robert Avatar
155 months ago
Macs were never as secure as PCs but they were unpopular enough that nobody bothered to attempt to exploit them. Now it seems that every other day there's another massive security flaw found in Mac OS X.

What security flaw are you referring to with this story?
Score: 9 Votes (Like | Disagree)
vmistery Avatar
155 months ago
Macs were never as secure as PCs but they were unpopular enough that nobody bothered to attempt to exploit them. Now it seems that every other day there's another massive security flaw found in Mac OS X.

You missed patch Tuesday then?
Score: 9 Votes (Like | Disagree)