Snow Leopard could level security playing field

Friday's release of the new version of the Mac OS, dubbed Snow Leopard, could include some security features that would make it secure, or at least push it closer to the level of security that Vista and Windows 7 have, experts said this week.

Contrary to popular Mac fanboy belief, Macintosh is not more secure from a software standpoint than modern Windows; it's merely safer to use because malware writers prefer to target the platform with the biggest install base, according to Charlie Miller and Dino Dai Zovi, co-authors of The Mac Hacker's Handbook, which came out this spring.

"Apple hasn't implemented all the security features that Vista has," Miller said. "They made some improvements in Leopard, but they are still behind."

If there is any truth to rumors circulating about Snow Leopard, the operating system security playing field could become more level as of this weekend and Mac users will really have something to brag about.

First off, a screen shot published on the Mac Security Blog of Intego on Tuesday appears to show a security feature supposedly in Snow Leopard that looks like it is detecting a Trojan in a disk image being downloaded via Safari. The post cites unnamed reports about an anti-malware feature being added.

"If it's true, it will mark a fundamental change in that Apple will be admitting that their operating system is as susceptible to malware as other operating systems," Miller said.

CNET's review of Snow Leopard posted late on Wednesday says that File Quarantine, first introduced in Mac OS X 10.4 Tiger, has been refined in Snow Leopard. File Quarantine checks for known malware signatures and displays an alert dialog if it finds a known offender and will be automatically updated via Mac OS X's software update as new malware signatures are found in the wild, the review says.

It's unclear whether rumors are true that Snow Leopard includes several internal features designed to prevent attacks that Vista and Windows 7 have, known as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) on that platform.

By randomizing the location of key pieces of data, ASLR makes it much more difficult for attackers to predict where data is going to be in order to execute their code or the code resident in the process. For exploit code that gets past the ASLR barrier, DEP will try to block it from running, recognizing that it is data and not a legitimate code.

"If you have both, it's hard for an exploit to get around it. Leopard has some ASLR but everything is not randomized and Leopard has no DEP," Miller said. "Things could change significantly for the Mac if they do a good job...That was my main gripe with it."

In June, Dai Zovi reported on a new local privilege escalation vulnerability researchers had discovered that gives local root access on Mac OS X Tiger and Leopard. He offered up a wish list for Snow Leopard that included: real" ASLR; "full use of hardware-enforced Non-eXecutable memory (NX);" default 64-bit native execution for security-sensitive processes; sandbox policies for Safari, Mail.app, and third-party applications (akin to what Chrome has); and Mandatory code signing for kernel extensions.

Apple's Mac OS X security page makes reference to offering sandboxing, Library Randomization, and Execute Disable, but there are no details.

An Apple spokeswoman did not follow up on an e-mail request seeking an interview for this story.

The Snow Leopard Web site says it will offer protection against some common types of heap buffer overflow exploits but not new types of such memory overflow exploits, according to Dai Zovi.

The security level in Leopard falls in between Windows XP Service Pack 2 and Vista, he said. If Snow Leopard has full ASLR and DEP, it would bring its security close to the level of Vista, he added.

While adding full ASLR and DEP to Snow Leopard will boost the operating system's defenses against targeted attacks, the Mac OS software arguably has more holes that malware can slip through, Miller said. "It would be fair to say that Mac has more bugs, but it's impossible to measure," he said.

Market pressure has been missing
In this sense, Microsoft has benefited greatly from the plague of security holes in early Windows versions. Those problems led the company to embark on a quasi-religious conversion in 2002 with Bill Gates launching the Trustworthy Computing initiative and setting security as a top priority for the company. Its Security Development Lifecycle (SDL) program--designed to build security into the software--has become the model for the industry.

Microsoft puts "much more effort into auditing their code, the entire SDL process, developer training, automated source code scanners, and hiring external penetration testers," Dai Zovi said.

So far, Apple hasn't felt that kind of market pressure to improve Mac security, largely because malware writers have ignored it, so its secure software development process isn't nearly as developed or mature as Microsoft's, the security researchers said.

"Microsoft has had a head start. That's why they had ASLR and DEP first," Miller said. "It's not because they're geniuses. They just started caring about it sooner."

"These things go lock in step and it doesn't make sense for businesses to expend a ton of resources when the threat is not there," said Dai Zovi. "So far, Apple has been keeping up pretty well with the level of threats in the wild."

As far as security goes, market share is a double-edged sword. As the Mac operating system gets more popular, the amount of malware targeting it is growing.

The Mac has only about 5 percent market share worldwide (nearly half is in the U.S. alone), compared with nearly 95 percent for Windows, according to market statistics provider Net Applications. But the Mac share is rising, from 3.73 percent to 4.86 percent in less than a year, the firm says.

In the meantime, more and more Mac malware is appearing. Earlier this week, TrendMicro reported that it found a new variant of the JAHLAV family of Trojans that pose as pirated versions of legitimate applications, modify a computer's domain name system (DNS) settings and enabling successful phishing attacks and redirects to sites hosting malware. Earlier versions of the Trojan masqueraded as versions of QuickTime, but this one passes as Foxit Reader or an antivirus program.

Some malware is written for both Windows and Mac platforms and downloads the correct version depending on the browser. Last week, Symantec reported that sites purporting to show streams of new movies were actually feeding up a DNS-changing Trojan instead called OSX.RSPlug.A for Mac and Trojan.Fakeavalert for Windows. Last month, a McAfee blog post wrote about the OSX/Puper.a Trojan that is downloaded onto Mac systems when users download what they think is a video player.

ZDNet's Zero Day blog has covered a number of Mac malware threats this year alone. In January, Intego, which has been tracking Mac malware for several years, discovered a Mac OS X Trojan circulating in pirated copies of Apple's iWork '09 software found on BitTorrent trackers and other sites. Symantec researchers in April linked malware found in bogus copies of iWork '09 and Adobe Photoshop CS4 to what they said could be the first Mac OS X botnet launching denial-of-service attacks. And in May, a new e-mail worm dubbed OSX/Tored-A targeting the Mac was uncovered, although it was not found to be spreading in the wild.

"The frequency is increasing" for Mac threats in the wild, said Dai Zovi. "Still, there are only a handful of threats; no where near what Windows users face."

In addition to considering how buggy the software is, how secure the operating system code is, and whether malware writers are creating viruses and Trojans for the platform, another factor in play is how likely Mac users are to be duped into visiting a malicious site, opening a malicious e-mail attachment, and downloading a fake file.

Most Mac users seem to take pride in their supposed invulnerability, so one would think that they are less cautious in their surfing activities. But it's hard to tell.

"No computer or operating system is more or less secure when it comes to users being tricked into downloading something," Miller said.