Apple Updates Malware Definitions to Protect Against Botnet Threat Coordinated Via Reddit
Last week, Russian anti-virus firm Doctor Web disclosed a newly discovered piece of OS X malware known as Mac.BackDoor.iWorm that at the time had affected roughly 17,000 machines around the world. While the exact mechanism of infection was unclear, an interesting twist to the story involves compromised machines running search queries on Reddit to obtain instructions about which command and control servers should be used to manage the botnet.
It is worth mentioning that in order to acquire a control server address list, the bot uses the search service at reddit.com, and -- as a search query -- specifies hexadecimal values of the first 8 bytes of the MD5 hash of the current date. The reddit.com search returns a web page containing a list of botnet C&C servers and ports published by criminals in comments to the post minecraftserverlists under the account vtnhiaovyd.
Once connected to a command and control server, the backdoor opened by the malware on the user's system can receive instructions to perform a variety of tasks, from stealing sensitive information to receiving or spreading additional malware.
In an effort to address the threat, Apple has now updated its "Xprotect" anti-malware system to recognize two different variants of the iWorm malware and prevent them from being installed on users' machines.

First introduced with OS X Snow Leopard, Xprotect is a rudimentary anti-malware system that recognizes and alerts users to the presence of various types of malware. Given the relative rarity of malware targeting OS X, the malware definitions are updated infrequently, although users' machines automatically check for updates on a daily basis. Apple also uses the Xprotect system on occasion to enforce minimum version requirements for plug-ins such as Flash Player and Java, forcing users to upgrade from older versions known to carry significant security risks.
Popular Stories
Apple's next-generation iPhone 17 Pro and iPhone 17 Pro Max are less than three months away, and there are plenty of rumors about the devices.
Apple is expected to launch the iPhone 17, iPhone 17 Air, iPhone 17 Pro, and iPhone 17 Pro Max in September this year.
Below, we recap key changes rumored for the iPhone 17 Pro models:Aluminum frame: iPhone 17 Pro models are rumored to have an...
Apple is developing a MacBook with the A18 Pro chip, according to findings in backend code uncovered by MacRumors.
Earlier today, Apple analyst Ming-Chi Kuo reported that Apple is planning to launch a low-cost MacBook powered by an iPhone chip. The machine is expected to feature a 13-inch display, the A18 Pro chip, and color options that include silver, blue, pink, and yellow.
MacRumors...
In 2020, Apple added a digital car key feature to its Wallet app, allowing users to lock, unlock, and start a compatible vehicle with an iPhone or Apple Watch. The feature is currently offered by select automakers, including Audi, BMW, Hyundai, Kia, Genesis, Mercedes-Benz, Volvo, and a handful of others, and it is set to expand further.
During its WWDC 2025 keynote, Apple said that 13...
Apple hasn't updated the AirPods Pro since 2022, and the earbuds are due for a refresh. We're counting on a new model this year, and we've seen several hints of new AirPods tucked away in Apple's code. Rumors suggest that Apple has some exciting new features planned that will make it worthwhile to upgrade to the latest model.
Subscribe to the MacRumors YouTube channel for more videos.
Heal...
Apple is planning to launch a low-cost MacBook powered by an iPhone chip, according to Apple analyst Ming-Chi Kuo.
In an article published on X, Kuo explained that the device will feature a 13-inch display and the A18 Pro chip, making it the first Mac powered by an iPhone chip. The A18 Pro chip debuted in the iPhone 16 Pro last year. To date, all Apple silicon Macs have contained M-series...
Popular accessory maker Anker this month launched two separate recalls for its power banks, some of which may be a fire risk.
The first recall affects Anker PowerCore 10000 Power Banks sold between June 1, 2016 and December 31, 2022 in the United States. Anker says that these power banks have a "potential issue" with the battery inside, which can lead to overheating, melting of plastic...
Chase this week announced a series of new perks for its premium Sapphire Reserve credit card, and one of them is for a pair of Apple services.
Specifically, the credit card now offers complimentary annual subscriptions to Apple TV+ and Apple Music, a value of up to $250 per year.
If you are already paying for Apple TV+ and/or Apple Music directly through Apple, those subscriptions will...
As part of its 10-year celebrations of Apple Music, Apple today released an all-new personalized playlist that collates your entire listening history.
The playlist, called "Replay All Time," expands on Apple Music's existing Replay features. Previously, users could only see their top songs for each individual calendar year that they've been subscribed to Apple Music, but now, Replay All...