A new version of Xagent, malware reportedly created by Russian hacking group APT28, has been discovered, and this version targets Mac users.

As outlined in a blog post by antivirus company Bitdefender (via Ars Technica), Xagent has previously been used to infiltrate Windows, iOS, Android, and Linux devices, but now Macs are vulnerable to attack as well. This is the first version of Xagent that's believed to be able to infiltrate Macs.

macbook pros 2015
The Mac version of Xagent is described as a backdoor that can be customized to do things like log passwords, detect system configurations, execute files, take screenshots of the display, and access iOS backups stored on the Mac.

The sample we are discussing today has been linked to the Mac OSX version of Xagent component from Sofacy/APT28/Sednit APT. This modular backdoor with advanced cyber-espionage capabilities is most likely planted on the system via the Komplex downloader.

Once successfully installed, the backdoor checks if a debugger is attached to the process. If it detects one, it terminates itself to prevent execution. Otherwise, it waits for an Internet connection before initiating communication with the C&C servers.

After the communication has been established, the payload starts the modules. Our preliminary analysis shows most of the C&C URLs impersonate Apple domains.

APT28 is the cyberespionage group that has been accused of hacking into the U.S. Democratic National Committee last year and interfering with the 2016 presidential election.

Bitdefender isn't entirely sure how the Mac version of Xagent is being distributed to users, but it could be spread via a macOS malware downloader called Komplex, which exploits a vulnerability in the virus-like MacKeeper software. Research on the malware is ongoing.

Mac users concerned about Xagent should avoid downloading anything that doesn't come from the Mac App Store or a well-known developer.

Note: Due to the political nature of the discussion regarding this topic, the discussion thread is located in our Politics, Religion, Social Issues forum. All forum members and site visitors are welcome to read and follow the thread, but posting is limited to forum members with at least 100 posts.

Top Rated Comments

bluespark Avatar
112 months ago
A malware discussion is political? Everyone should be able to comment on this.
Score: 19 Votes (Like | Disagree)
manu chao Avatar
112 months ago
Maybe it is time that MacKeeper is classified as malware by anti-malware applications ...
Score: 12 Votes (Like | Disagree)
keysofanxiety Avatar
112 months ago
Maybe it is time that MacKeeper is classified as malware by anti-malware applications ...
It is. MalwareBytes deletes it.
Score: 5 Votes (Like | Disagree)
John.B Avatar
112 months ago
Mac users concerned about Xagent should avoid downloading anything that doesn't come from the Mac App Store or a well-known developer.
The attack vector is based on a vulnerability in Mackeeper.

Keep that off your Mac and you'll be fine.
Score: 5 Votes (Like | Disagree)
Kajje Avatar
112 months ago
Installation of that Mackeeper pest should be blocked on firmware level.
Score: 2 Votes (Like | Disagree)
997440 Avatar
112 months ago
More information on this issue from @thomasareed. He's unable to post here because he has less than 100 posts.

He wanted to let us "know that this new "XAgent" variant of Komplex has absolutely no relation to a MacKeeper exploit. The writer has conflated this variant with one specific older variant from 2015. As much as I'd like to be able to blame MacKeeper, that vulnerability was closed in 2015, and there's no indication whatsoever that MacKeeper is in any way involved with the "XAgent" variant."





(Mr. Reed works for Malwarebytes and codes Malwarebytes Anti-Malware for Mac. Prior to this he developed Adware Medic and wrote extensively about security matters, and other Mac matters, at thesafemac((dot))com.)
Score: 2 Votes (Like | Disagree)

Popular Stories

iPhone 17 Pro 3 4ths Perspective Aluminum Camera Module 1

New iPhone 17 Pro Details: Brighter Display, Best Battery Life, and More

Wednesday September 3, 2025 5:33 am PDT by
Apple's iPhone 17 Pro and iPhone 17 Pro Max models will feature a number of significant display, thermal, and battery improvements, according to new late-stage rumors. According to the Weibo leaker known as "Instant Digital," the iPhone 17 Pro models will feature displays with higher brightness, making it more suitable for use in direct sunlight for prolonged periods. The iPhone 16 Pro and...
iPhone 17 Pro Iridescent Feature 2

iPhone 17 and iPhone 17 Pro Prices Estimated Ahead of Apple Event Next Week

Tuesday September 2, 2025 1:50 pm PDT by
Just one week before Apple is expected to unveil the iPhone 17 series, an analyst has shared new price estimates for the devices. Here are J.P. Morgan analyst Samik Chatterjee's price estimates for the iPhone 17 series in the United States, according to 9to5Mac: Model Starting Price Model Starting Price Change iPhone 16 $799 iPhone 17 ...
iPhone 17 Pro Iridescent Feature 2

iPhone 17 Pro Clear Case Leak Reveals Three Key Changes

Sunday August 31, 2025 1:26 pm PDT by
Apple is expected to unveil the iPhone 17 series on Tuesday, September 9, and last-minute rumors about the devices continue to surface. The latest info comes from a leaker known as Majin Bu, who has shared alleged images of Apple's Clear Case for the iPhone 17 Pro and Pro Max, or at least replicas. Image Credit: @MajinBuOfficial The images show three alleged changes compared to Apple's iP...
iphone 16 pro ghost hand

iPhone 17 Pro: 5 Reasons Not to Upgrade This Year

Monday September 1, 2025 4:35 am PDT by
Apple will launch its new iPhone 17 series this month, and the iPhone 17 Pro models are expected to get a new design for the rear casing and the camera area. But more significant changes to the lineup are not expected until next year, when the iPhone 18 models arrive. If you're thinking of trading in your iPhone for this year's latest, consider the following features rumored to be coming to...
iPhone 17 Pro Dark Blue and Orange

iPhone 17 Release Date, Pre-Orders, and What to Expect

Thursday August 28, 2025 4:08 am PDT by
An iPhone 17 announcement is a dead cert for September 2025 – Apple has already sent out invites for an "Awe dropping" event on Tuesday, September 9 at the Apple Park campus in Cupertino, California. The timing follows Apple's trend of introducing new iPhone models annually in the fall. At the event, Apple is expected to unveil its new-generation iPhone 17, an all-new ultra-thin iPhone 17...
Apple Watch Ultra 2 Complications

Apple Watch Ultra 3 Coming Next Week: Eight Reasons to Upgrade

Thursday September 4, 2025 7:38 am PDT by
We're only days away from Apple's "Awe dropping" fall event scheduled to take place on Tuesday, September 9 – and along with the new iPhone 17 series, we're going to get a new version of the Apple Watch Ultra for the first time since 2023. By the time the Ultra 3 is unveiled, it will have been two years since the previous model arrived. The intervening period has left plenty of room for...