First Mac Ransomware Found in Transmission BitTorrent Client - MacRumorsOpen MenuShow RoundupsShow Forums menuVisit ForumsOpen Sidebar
Skip to Content

First Mac Ransomware Found in Transmission BitTorrent Client

transmission-29
This weekend, a notice appeared on Transmissionbt.com warning users that version 2.90 of the popular Mac BitTorrent client downloaded from their site may have been infected with malware. The warning reads:

Everyone running 2.90 on OS X should immediately upgrade to 2.91 or delete their copy of 2.90, as they may have downloaded a malware-infected file.

Using “Activity Monitor” preinstalled in OS X, check whether any process named “kernel_service” is running. If so, double check the process, choose the “Open Files and Ports” and check whether there is a file name like “/Users//Library/kernel_service”. If so, the process is KeRanger’s main process. We suggest terminating it with “Quit -> Force Quit”

Reuters reports that the infected download contained the first "Ransomware" found on the Mac platform. Ransomware is a type of malware that encrypts a user's hard drive and demands payment in order to unencrypt it. This type of attack has been increasingly popular on the PC, but this is the first time it has been seen on the Mac.

According to Reuters, Apple is aware of the issue and has already revoked "a digital certificate from a legitimate Apple developer that enabled the rogue software to install on Macs."

The malware in question is said to delay encrypting the user's hard drive for 3 days, so we may see the first reports of those affected as early as Monday. Transmissionbt.com offers instructions on how to see you are affected (above). If you don't use the Transmission software, there is nothing you need to do at this time.

Update: Technical details about the malware.

Update 2: Transmissionbt.com says version 2.92 of Transmission will actively remove the malware.

Popular Stories

iOS 27 Next to iPhone

Here's When iOS 27 Rolls Out Today in Every Time Zone [Update: It's Out]

Sunday September 13, 2026 3:00 am PDT by
Update 10:04 a.m.: iOS 27 is rolling out now, though it may take a bit for all users to see it, so keep checking! Apple is about to release iOS 27, which will finally deliver more advanced Siri AI capabilities as well as a variety of other refinements, improvements, and new features to iPhones. It's Apple's biggest software update of the year, and Apple announced at Wednesday's iPhone event...
iOS 27 Icon iPhone

iOS 27 Available Now With These 8 New Features

Monday September 14, 2026 9:00 am PDT by
Update — 10 a.m. Pacific Time: Apple has released iOS 27. During its iPhone 18 Pro and iPhone Duo event last week, Apple announced that iOS 27 will be released widely on Monday, September 14. iOS 27 should be available around 10 a.m. Pacific Time / 1 p.m. Eastern Time today via the Settings app, under General → Software Update. Below, we have highlighted eight new features and...
Apple iCloud Plus expansion hero

iCloud+ Now Includes Apple TV, Apple Arcade, and Curated Apple Music Stations in Over 100 Countries

Tuesday September 15, 2026 1:43 am PDT by
Apple today announced a new subscription initiative that turns paid iCloud+ subscriptions into a broader services bundle in more than 100 countries. In select countries, Apple says every paid iCloud+ plan, including the cheapest 50GB tier, now includes Apple TV and Apple Arcade "at no additional cost," while family sharing extends the storage, TV and Arcade access to up to five people....

Top Rated Comments

stridemat Avatar
137 months ago
to be expected when people use BitTorrent, I have zero sympathy for people who pirate stuff!
Whilst most the time both go hand in hand, BitTorrent is just a method of file transfer and not directly related to piracy.
Score: 52 Votes (Like | Disagree)
8692574 Avatar
137 months ago
Cant really blame Apple for data loss if you
(a) Don't make regular backups
(b) Install bit torrent clients (from a website no less) Which have little or no legitimate use other than piracy
to be expected when people use BitTorrent, I have zero sympathy for people who pirate stuff!
Torrent are used for more than piracy my friend, we are not in the early 2000 anymore!!

All Linux distribution are downoadable with torrent and they are 100% legit!
Score: 32 Votes (Like | Disagree)
137 months ago
Lol, I don't think I've met an even SLIGHTLY savvy computer user (Mac or PC) in the last eight years or so that uses a client other than uTorrent.
Given that ALL torrent apps are free, why would anyone download this????????
Stability and no ads. Never had a problem with Transmission as my default client.
Score: 27 Votes (Like | Disagree)
137 months ago
Apparently it only affects users who downloaded it off of the website and not those who used the in app update.
Score: 27 Votes (Like | Disagree)
137 months ago
... if you use time machine
Cant really blame Apple for data loss if you
(a) Don't make regular backups
(b) Install bit torrent clients (from a website no less) Which have little or no legitimate use other than piracy
Score: 26 Votes (Like | Disagree)
Weaselboy Avatar
137 months ago
Looks like Apple has updated XProtect for this KeRanger malware already. This is from my xprotect.plist file.



Attachment Image
Score: 24 Votes (Like | Disagree)