Flashback Trojan Returns With a Multi-Pronged Infection Strategy

Last year, we profiled a Mac trojan horse known as "Flashback" that was masquerading as a Flash Player installer. While Apple has taken steps to protect users from the threat using its File Quarantine system under which users' computers initiate daily checks for updated malware definitions, the malware's authors have continued to tweak the trojan to improve its ability to both infect systems and evade detection.

Security firm Intego has issued a report on a new variant of the trojan, known as Flashback.G, which adopts a multi-pronged strategy in attacking users' systems. The first two methods rely on vulnerabilities in Java, and while the vulnerabilities are patched in systems running up-to-date versions of Java, outdated systems can be silently infected through these security holes.


Flashback.G's self-signed certificate seeking to trick users into allowing installation

On up-to-date systems lacking the Java vulnerabilities, Flashback.G presents a self-signed certificate claiming to be from Apple in an attempt to fool users into allowing the trojan to be installed on their systems. Once installed, the trojan begins searching for user names and passwords it can relay to the malware's authors.

This malware patches web browsers and network applications essentially to search for user names and passwords. It looks for a number of domains – websites such as Google, Yahoo!, CNN; bank websites; PayPal; and many others. Presumably, the people behind this malware are looking for both user names and passwords that they can immediately exploit – such as for a bank website – as well as others that may be reused on different sites.

Notably, Intego reports that the trojan aborts its own installation if it detects the presence of any of several antivirus applications on a user's Mac, presumably seeking to remain below the radar while focusing on vulnerable systems.

Intego recommends that users on Mac OS X Snow Leopard make sure that Java is fully up-to-date by running a check through Software Update, and for all users to be aware of the social engineering trick the trojan uses in attempting to gain permission for installation. The company of course also recommends that users equip their systems with antivirus software.

While malware has not been a tremendous threat to Mac users so far, its presence has been growing. Apple has stepped up its efforts to combat malware by enhancing its File Quarantine system to provide for the daily definition checks. OS X Mountain Lion will see another significant step with the introduction of Gatekeeper, a system by which users can limit installation of apps to sources such as the Mac App Store and developers who have registered with Apple as "identified developers".

Apple's Developer-ID program will utilize digital signatures on applications to link applications with a specific developer. If the developer is later discovered to be distributing malware or otherwise behaving improperly, installations of its existing apps can be deactivated by Gatekeeper. Gatekeeper does have its limitations, however, as it only scans applications downloaded through a handful of mechanisms such as browsers and can not detect applications that are modified by malware after their initial launch.

Top Rated Comments

(View all)
Avatar
112 months ago
and this is why the 2 most important parts of computing are:

1. keep your computer up-to-date

and

2. use a little common sense when something pops up (though I admit that is easier to more knowledgeable people like us than the wider 'mass' consumer)
Score: 32 Votes (Like | Disagree)
Avatar
112 months ago

Apple computers do not get a virus. Yeah right. (as the Tui advertisment goes).


Trojan != Virus
Score: 30 Votes (Like | Disagree)
Avatar
112 months ago

Whatever, still malware.


It sounds pedantic, but it is sort of an important distinction to make. Viruses can be spread without any user input, while trojans still require the user to at some point (albeit unknowingly) permit them.
Score: 21 Votes (Like | Disagree)
Avatar
112 months ago

Apple computers do not get a virus. Yeah right. (as the Tui advertisment goes).

First off, no one in any position of authority has ever said Macs don't or can't get viruses.

Secondly, this is a trojan, so talking about viruses here is kind of beside the point.


And to think people said that the fact that OS X lacked malware had nothing to do with it's marketshare.

Their computer marketshare is far, far larger than their malware market share.

So yeah, I'm STILL saying that there are other factors at play. If that wasn't true you'd see malware market share matching sales market share. And that hasn't happened.
Score: 18 Votes (Like | Disagree)
Avatar
112 months ago

And to think people said that the fact that OS X lacked malware had nothing to do with it's marketshare.

The argument has usually been applied to viruses. Trojans require user input and can effect anything. Yes, security holes are taken advantage of to make this Trojan look legit, but there is no defense for the most basic Trojan. If I wrote and app that said you'll be granted three wishes after you enter your password, but instead I use your password to delete all files on you computer, that is a Trojan. There is no defense for such things expect common sense.

Whatever, still malware.

It's a huge distinction.

So for those of us who got their parents Macs..

Anyone recommend a good A/V program while we wait for ML to come out?

The best AV program is to not download from or even visit shady sites.
Score: 16 Votes (Like | Disagree)
Avatar
112 months ago
Why is "Continue" the default choice when the root certificate is not trusted?
Score: 13 Votes (Like | Disagree)

Top Stories

iPhone 12 Lineup Rumored to Be Named 'iPhone 12 mini,' 'iPhone 12,' 'iPhone 12 Pro,' and 'iPhone 12 Pro Max'

Monday September 21, 2020 5:24 am PDT by
Leaker known as "L0vetodream" has today shared the alleged naming for the upcoming iPhone 12 lineup on Twitter. The tweet proposes that the upcoming iPhone 12 models will be titled "iPhone 12 mini," "iPhone 12," "iPhone 12 Pro," and "iPhone 12 Pro Max." The names likely correspond to the three expected sizes of iPhone 12, with the 5.4-inch model being the iPhone 12 mini, the 6.7-inch model ...

iOS 14 Widgets Offer iPhone Users Creative Home Screen Ideas

Sunday September 20, 2020 8:43 pm PDT by
Updated on September 22nd with hands on video. In iOS 14, Apple introduced ‌the concept of Home Screen‌ widgets, which provide information from apps at a glance. Widgets can be pinned to the Home Screen in various spots and sizes, allowing for many different layouts. Despite the relative lack of...

Hands-On With iOS 14 Widgets, Custom Icons, and Home Screen Setup

Tuesday September 22, 2020 3:25 pm PDT by
Apple with iOS 14 introduced widgets on the Home Screen, leading to unprecedented levels of customization for the iPhone. Combined with Shortcuts that let you change an app's icon, iOS 14 lets you create a whole new look for your Home Screen. Subscribe to the MacRumors YouTube channel for more videos. We've been following along with some of the creative alternative Home Screen designs that M...

PSA: New Apple Watch Owners Have to Return Entire Device for Ill-Fitting Solo Loop or Braided Solo Loop

Monday September 21, 2020 3:26 pm PDT by
With the Apple Watch Series 6, Apple introduced two new band options, the Solo Loop and the Braided Solo Loop. These new bands are unique because they have no clasps, buckles, or other fasteners, and instead use a stretch design to allow them to pull onto the wrist over the hand. Because these bands are not adjustable, Apple sells each one in nine different sizes to make sure each person...

Apple's iPhone 12 Event Could Happen on October 13 Based on Rumors From Mobile Operators

Wednesday September 23, 2020 11:51 am PDT by
Apple's upcoming iPhone-centric event could perhaps be held on Tuesday, October 13, according to information shared with MacRumors by an employee at a UK cellular carrier. There's no way for us to confirm the dates at this point in time nor are we sure on the credibility of the source, but even without a rumor, Tuesday, October 13 is a good guess based on Apple's historic launch timelines, ...

New Images Leak of iPhone 12 Braided USB-C to Lightning Cable

Thursday September 24, 2020 2:37 am PDT by
Rumors suggest Apple's upcoming iPhone 12 models will ship with a new Lightning to USB-C cable that includes a braided fabric design. Images of the purported cables were leaked in July, and today leaker Mr White has shared new images that give us a closer look at what we might get included in the iPhone 12 box. The photos show a USB-C to Lightning cable with a clearly braided design rather...

Interest in iOS 14 Home Screen Ideas Helps Pinterest Break Daily Download Record

Wednesday September 23, 2020 4:37 am PDT by
Apple's introduction of widgets on the Home Screen in iOS 14 has driven a surge in interest among users looking to customize their iPhone, and that has reportedly had a knock-on effect for Pinterest, whose iOS app has seen record downloads as users flock to its content seeking design inspiration. As reported by TechCrunch, App Store intelligence firm Apptopia was first to note the impact of ...

Apple Releases First Public Betas of iOS 14.2 and iPadOS 14.2 With New Shazam Control Center Options

Monday September 21, 2020 10:34 am PDT by
Apple today seeded the first public betas of upcoming iOS 14.2 and iPadOS 14.2 updates to its public beta testing group, a few days after seeding the first betas to developers and a little less than a week after releasing the iOS 14 and iPadOS 14 updates. Public beta testers who have signed up for Apple's beta testing program can download the iOS and iPadOS‌ 14.2 updates over the air after ...

Apple Emphasizes That Solo Loop May Increase in Length Over Time, Updates Sizing Guide With More Specific Instructions

Wednesday September 23, 2020 8:26 am PDT by
Apple on Tuesday updated one of its support documents to emphasize that the new silicone rubber Solo Loop for the Apple Watch may increase in length over time, as mentioned in fine print at the bottom of the Solo Loop product page. Apple has also updated its printable Solo Loop sizing guide with more specific instructions, as noted by 9to5Mac's Michael Steeber. The guide now advises users to ...

Microsoft Announces Outlook for Mac Redesign, Improvements to iOS and watchOS Apps

Tuesday September 22, 2020 8:56 am PDT by
Microsoft has today announced plans to bring a new design to its Outlook for Mac app along with several other improvements and features for Outlook on iOS and watchOS. In preparation for the public release of macOS Big Sur, Microsoft has been testing a new design for Outlook on Mac. The design includes Microsoft's Fluent icons and several design cues from Big Sur such as rounded corners....