Feeds

Flashback trojan targeting OS X shuns virtual machines

Mac malware grows up

Choosing a cloud hosting partner with confidence

Underscoring the growing sophistication of Mac-based malware, a trojan preying on OS X users has adopted several stealth techniques since it was discovered last month.

Updates to the Flashback trojan, which gets installed by disguising itself as an Adobe Flash update, now prevent the malware from running on Macs that use VMware Fusion. Such virtual machine software is routinely used by security researchers to test the behavior of a malware sample because it's easier to delete a virtual instance when they're finished than it is to wipe the hard drive clean and reinstall the operating system.

When users get tricked into clicking on the recently introduced Flashback.D installer, the program checks to see if the Mac is running Fusion. If it is, it doesn't execute, researchers from antivirus provider Intego blogged on Thursday. Windows malware has done the same thing for years.

Flashback developers have also rejiggered their code so that it no longer installs itself in an easy-to-spot subfolder off the OS X ~/Library location. Instead, it plants a backdoor inside a more obscure folder associated with the Safari. Deleting the files prevents the browser from working.

Such virtual-machine blocking and cloaking of malicious files have become standard fare in Windows malware. Their addition to Flashback suggests the same techniques are being adopted by criminals targeting Macs.

“These changes show that the malware authors are sophisticated, and that they're altering their code to ensure that the malware is not detected,” Intego researchers wrote.

A separate post from researchers at competing antivirus firm F-Secure said the VM-awareness dates back to the release of the earlier Flashback.B version of the malware.

“It appears that Mac malware authors are anticipating that researchers will begin to use virtualized environments during analysis, and are taking steps to hamper such efforts,” the post stated.

Developers are bringing additional innovations to Mac malware. According to security reporter Brian Krebs, Trojan-Dropper: OSX/Revir.A, another recently discovered Mac trojan, “challenges a widely-held belief among Mac users that malicious software cannot install without explicit user permission.” ®

Top 5 reasons to deploy VMware with Tegile

More from The Register

next story
Regin: The super-spyware the security industry has been silent about
NSA fingered as likely source of complex malware family
Why did it take antivirus giants YEARS to drill into super-scary Regin? Symantec responds...
FYI this isn't just going to target Windows, Linux and OS X fans
Privacy bods offer GOV SPY VICTIMS a FREE SPYWARE SNIFFER
Looks for gov malware that evades most antivirus
Patch NOW! Microsoft slings emergency bug fix at Windows admins
Vulnerability promotes lusers to domain overlords ... oops
HACKERS can DELETE SURVEILLANCE DVRS remotely – report
Hikvision devices wide open to hacking, claim securobods
'Regin': The 'New Stuxnet' spook-grade SOFTWARE WEAPON described
'A degree of technical competence rarely seen'
Astro-boffins start opening universe simulation data
Got a supercomputer? Want to simulate a universe? Here you go
You stupid BRICK! PCs running Avast AV can't handle Windows fixes
Fix issued, fingers pointed, forums in flames
prev story

Whitepapers

Designing and building an open ITOA architecture
Learn about a new IT data taxonomy defined by the four data sources of IT visibility: wire, machine, agent, and synthetic data sets.
Why CIOs should rethink endpoint data protection in the age of mobility
Assessing trends in data protection, specifically with respect to mobile devices, BYOD, and remote employees.
Getting started with customer-focused identity management
Learn why identity is a fundamental requirement to digital growth, and how without it there is no way to identify and engage customers in a meaningful way.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Security and trust: The backbone of doing business over the internet
Explores the current state of website security and the contributions Symantec is making to help organizations protect critical data and build trust with customers.