Feeds

Flashback trojan targeting OS X shuns virtual machines

Mac malware grows up

The Essential Guide to IT Transformation

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.” ®

Build a business case: developing custom apps

More from The Register

next story
14 antivirus apps found to have security problems
Vendors just don't care, says researcher, after finding basic boo-boos in security software
'Things' on the Internet-of-things have 25 vulnerabilities apiece
Leaking sprinklers, overheated thermostats and picked locks all online
iWallet: No BONKING PLEASE, we're Apple
BLE-ding iPhones, not NFC bonkers, will drive trend - marketeers
Only '3% of web servers in top corps' fully fixed after Heartbleed snafu
Just slapping a patched OpenSSL on a machine ain't going to cut it, we're told
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Israel's Iron Dome missile tech stolen by Chinese hackers
Corporate raiders Comment Crew fingered for attacks
Tor attack nodes RIPPED MASKS off users for 6 MONTHS
Traffic confirmation attack bared users' privates - but to whom?
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
Researcher sat on critical IE bugs for THREE YEARS
VUPEN waited for Pwn2Own cash while IE's sandbox leaked
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Maximize storage efficiency across the enterprise
The HP StoreOnce backup solution offers highly flexible, centrally managed, and highly efficient data protection for any enterprise.