Feeds

New OS X research warns of stealthier Mac attacks

In-memory code injection covers tracks

The Essential Guide to IT Transformation

A computer security researcher has discovered a new way to inject hostile code directly into the memory of machines running Apple's OS X operating system, a technique that makes it significantly harder for investigators to detect Mac attacks using today's forensics practices.

The technique, which Italian researcher Vincenzo Iozzo plans to detail at the Black Hat security conference in Washington next month, makes it possible to carry out stealthy Mac attacks that until now have not been possible. The in-memory injection approach allows unauthorized software to be installed on a Mac without leaving traces of the attack code or other tell-tale signs that the machine has been compromised.

Similar stealth techniques have existed for more than two years for infecting Windows and Linux machines, but until now, researchers knew of no reliable way to cover their tracks when attacking Macs. It's likely only a matter of time until malware developers begin using the method in the wild, said researcher Charles Miller, who has reviewed Iozzo's work.

"The importance is it makes forensics much harder," Miller wrote in an email to The Register. "In the past, you could rely on seeing the trail of the bad guy on the disk, even if they tried cleaning up and deleting their files. This provides a practical method to eliminate that evidence."

Miller said he is in the process of extending the technique to installing unauthorized applications on the iPhone.

Unlike most attacks today, Iozzo's technique allows someone to execute a binary completely within the OS X application or process that's being attacked. That means the operating system doesn't need to open a new process and the exploit code need not ever touch the hard disk of the infected machine. Such activities typically leave a wealth of clues to system administrators trying to tell whether a computer has been compromised.

A student at the Politecnico di Milano, Iozzo was able to fashion the exploit method by carefully monitoring the Mac executable file format known as Mach-O. By mimicking exactly the way OS X lays out executable code in memory, the researcher discovered a way to bypass more traditional ways of loading binaries into the operating system.

Iozzo said OS X's address space layer randomization, which is designed to thwart such attacks by randomizing the memory locations of executable code, can be circumvented by local users. That's because an OS X program known as the dynamic linker is always located at the same address. The dynamic linker in turn allows him to predict the location of other libraries needed to make the attack technique work.

To be clear, attackers who want to use the technique must first have a reliable exploit for an unpatched vulnerability in OS X or in iTunes, Safari, or some other OS X application. The injection method doesn't make it any easier to pierce a Mac's defenses. It only makes it easier for attackers to cover their tracks once they have.

Still, the technique doesn't make attacks completely undetectable. Investigators can still dump the virtual memory and inspect it or detect the attack by using a network intrusion detection system or a host-based anomaly intrusion detection system.

Be that as it may, don't be surprised if it finds its way into real-world attacks in the future.

"It's so easy to use," Miller said. "If I was a bad guy I'd use it. If you care about hiding yourself, it would be stupid not to use it." ®

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
Secure microkernel that uses maths to be 'bug free' goes open source
Hacker-repelling, drone-protecting code will soon be yours to tweak as you see fit
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
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
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.
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.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.