Apple Updates Anti-Malware Definitions to Address Fake Flash Player Trojan

flash player trojan
Fake Flash Player trojan installer

While things have been relatively quiet on the malware front for OS X since a raid on Russian payment processing firm ChronoPay appeared to have taken down MacDefender nearly two months ago, one new trojan horse did pop up earlier this month. As detailed by F-Secure, the trojan known as "OSX.QHost.WB.A" masquerades as a Flash Player installer but actually adds entries to a computer's hosts file to redirect users attempting to visit certain Google sites.

Once installed, the trojan adds entries to the hosts file to hijack users visiting various Google sites (e.g., Google.com.tw, Google.com.tl, et cetera) to the IP address 91.224.160.26, which is located in Netherlands.

The server at the IP address displays a fake webpage designed to appear similar to the legitimate Google site.

Search results on the fake Google pages actually lead to pop-up windows that load external content which was broken at the time of discovery but presumably consisted of advertisements of some sort. While the threat as implemented at the time of discovery was relatively mild, inexperienced users falling for the trojan could find themselves unaware of what had happened to their systems and how to fix the hijacked routing added by the malware.

osx qhost wb a
Consequently, Apple earlier this week made its first significant addition to its "XProtect.plist" file since the spate of MacDefender variants surfaced in June. The XProtect.plist file contains malware definitions to enable users' systems to recognize and warn users of malicious downloads, a feature that debuted with Mac OS X Snow Leopard back in 2009.

The original anti-malware system required manual updates to account for new threats, and as such was updated only rarely by Apple as part of larger software updates. But with an Apple software update issued in response to the MacDefender threat earlier this year, Mac OS X systems are now able to make daily checks for updates to that file to ensure up-to-date protection against malware.

Popular Stories

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, ...
Cyber Week Deals 2025

Best Cyber Week Apple Deals Include Big Discounts on AirPods, Apple Watch, and More

Sunday November 30, 2025 7:33 am PST by
Cyber Week is here, and you can find popular Apple products like AirPods, iPad, Apple Watch, and more at all-time low prices. In this article, the majority of the discounts will be found on Amazon. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a purchase, we may receive a small payment, which helps us keep the site running. Specifically,...
Netflix Smaller 4

Netflix Kills Casting From Its Mobile App to Most Modern TVs

Monday December 1, 2025 4:36 am PST by
Netflix has quietly removed the ability to cast content from its mobile apps to most modern TVs and streaming devices, including newer Chromecast models and the Google TV Streamer. The change was first spotted by users on Reddit and confirmed in an updated Netflix support page (via Android Authority), which now states that the streaming service no longer supports casting from mobile devices...
studio display purple february

M5 iPad Pro Could Hint at New Studio Display Feature

Sunday November 30, 2025 10:30 am PST by
The updated specs of the M5 iPad Pro may point toward a major new feature for Apple's next-generation Studio Display expected in early 2026. Apple's latest iPad Pro debuted last month and contains one display-related change that stands out: it can now drive external monitors at up to 120Hz with Adaptive Sync. The feature should deliver lower latency, smoother motion, and fewer visual...
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...
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...
maxresdefault

The MacRumors Show: Apple's Big Plans for iPad Mini 8

Friday November 28, 2025 8:39 am PST by
On this week's episode of The MacRumors Show, we talk through the latest rumors about Apple's upcoming iPad mini 8. Subscribe to The MacRumors Show YouTube channel for more videos The next-generation version of the iPad mini is expected to feature an OLED display, as part of Apple's plan to expand the display technology across many more of its devices. Apple's first OLED device was the Apple...
maxresdefault

iPhone Fold: Launch, Pricing, and What to Expect From Apple's Foldable

Monday December 1, 2025 3:00 am PST by
Apple is expected to launch a new foldable iPhone next year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that 2026 could indeed be the year that Apple releases its first foldable device. Subscribe to the MacRumors YouTube channel for more videos. Below, we've collated an updated set of key details that ...
Touchscreen MacBook Feature

Here Are the Four MacBooks Apple Is Expected to Launch Next Year

Monday December 1, 2025 5:00 am PST by
2026 could be a bumper year for Apple's Mac lineup, with the company expected to announce as many as four separate MacBook launches. Rumors suggest Apple will court both ends of the consumer spectrum, with more affordable options for students and feature-rich premium lines for users that seek the highest specifications from a laptop. Below is a breakdown of what we're expecting over the next ...

Top Rated Comments

KnightWRX Avatar
187 months ago
Let's get this out of the way right now : This is not an OS X virus.
Score: 36 Votes (Like | Disagree)
Stridder44 Avatar
187 months ago
Awesome, I was not aware that it updated daily.

And yes, this is not a virus. This is malware.
Score: 11 Votes (Like | Disagree)
longofest Avatar
187 months ago
No, it's not a "virus". It's a trojan. You think it's good, but its bad. (heh... depending on if you think "flash" is "good").

A question I have though, is under what conditions should ANY software modify the hosts file? Should Apple even allow programs that have been granted administrative rights to alter the hosts file? There is only a very limited benvolent use case for such an action, and that very related to what they did here: some anti-ad or anti-spyware utilities modify a host file to redirect known ad-producing domains to a "safe" domain. I personally think any modification of the host file should be given a warning like this:

The program _____ is trying to update a core Mac OS X system file that is used to provide network connectivity. While online advertisement blocking programs may require legitimate use of this file, most others applications may represent an attempt to install malicious software onto your computer. Are you sure you want to allow program _____ to modify this file?
Score: 9 Votes (Like | Disagree)
BC2009 Avatar
187 months ago
Funny.... I updated Flash yesterday on my kids' Mac mini and I thought that writing a Trojan that masquerades as an update to Flash would be brilliant since Flash is updated so often and getting prompted that you need to update Flash to view a website is very common..... And then today, here it is.
Score: 8 Votes (Like | Disagree)
Sjhonny Avatar
187 months ago
That's why you need to disable flash. :p

This has nothing to do with Flash.
Score: 8 Votes (Like | Disagree)
devilstrider Avatar
187 months ago
Been out of the loop for 10 weeks and MacRumors is getting my up to speed fast. I love this site.
Score: 8 Votes (Like | Disagree)