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Snow Leopard Missed a Security Opportunity
CWmike writes "Apple missed a golden opportunity to lock down Snow Leopard when it again failed to implement fully a security technology that Microsoft perfected nearly three years ago in Windows Vista, noted Mac researcher Charlie Miller said today. Dubbed ASLR, for address space layout randomization, the technology randomly assigns data to memory to make it tougher for attackers to determine the location of critical operating system functions, and thus makes it harder for them to craft reliable exploits. 'Apple didn't change anything,' said Miller, of Independent Security Evaluators, the co-author of The Mac Hacker's Handbook, and winner of two consecutive 'Pwn2own' hacker contests. 'It's the exact same ASLR as in Leopard, which means it's not very good.'"
Yeah, but it doesnt matter. everyone knows that apples are immume to viruses and malware. and they look better than ordinary Pcs.
Surely this is only of any use to a hacker if they manage to run in "ring zero" anyway. Otherwise wouldn't normal page protection stop them. Am I missing something?
The summary alleges Miller said it "today". Except he didn't.
The article linked to is dated September 14, which means he allegedly said it 2 days ago. Except he didn't.
He actually said it *two weeks ago* on August 29th.
Wake up, editors!
Call me a cynic, but I somehow think he, and everyone else that looks at OS security, will still find things to complain about. The tech blog and journalism industry depends on it!
Microsoft's Windows Vista and Windows Server 2008 have ASLR enabled by default, although only for those executables and dynamic link libraries specifically linked to be ASLR-enabled.[citation needed] This did not include Internet Explorer 7 on Windows Vista prior to Service Pack 1; ASLR and DEP are both disabled for application compatibility purposes. Newer versions, including Internet Explorer 8, enable these protections. A registry setting is available to forcibly enable or disable ASLR for all executables and libraries. The locations of the heap, stack, Process Environment Block, and Thread Environment Block are also randomized. A security whitepaper from Symantec noted that ASLR in 32-bit Windows Vista may not be as robust as expected, and Microsoft has acknowledged a weakness in its implementation.
It appears that only OpenBDD and some hardened Linuxes (not mainstream distributions) have a complete implementation.
ASLR makes executing code on the stack quite a bit more difficult, regardless of what privileges the program being exploited may have. Also makes calling libaray functions and pretty much anything in RAM far more difficult for a hacker. Page protection doesn't protect against these attacks per se.
Then how does your network card work?
1. You identify a system API that has a local escalation vulnerability. These aren't that uncommon and because they cannot be directly exploited remotely they're not generally as high of a priority.
2. You identify a vulnerability in a service or other application that permits execution of arbitrary code remotely.
3. You exploit the remotely exploitable vulnerability with a payload that calls into the known mapped address of the system API with a second payload in order to escalate to root and then execute a third payload with those increased privileges to outright p0wn the machine.
Linux's implementation of ASLR is substantially inferior to Windows Vista/7's, which was covered the FIRST time this guy won the pwn2own contest. However, it is far superior to OSX's, which appears to not really do anything useful, and which appears to have not even changed since it was discovered that OSX ASLR is useless. Please try to keep up, or don't comment. Thank you.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
It does not make it obscure, it makes it unpredictable.
You may figure out the location of something once, but it will be somewhere else on a different computer, or even on the same computer after a reboot.
The masses are the crack whores of religion.
If there's a phrase that should trigger skepticism, that's it. ASLR isn't "perfect", and has been reported (and confirmed) exploited as recently as 7 months ago:
--
make install -not war
As a long time Mac user, I completely agree with you. I have long thought Apple did not take security seriously or at least did not devote the resources they should on security matters. Worse, I absolutely do not want to go through a decade of painful and annoying security problems (like the windows users went through) before Apple begins to put real effort into security.
To be fair, Apple have focused much more on the user-facing side of the security problem. There's just much less likelihood of a user installing something bad by accident. Deliberate badness is a problem (always) but by reducing the problem with accidents, real on-the-ground disasters are lessened. (It helps that Mac applications are really directories, and so aren't quite as simple to start from some website by accident, and their filesystem-level metadata that marks downloaded things with where they came from also makes a difference.) Which isn't to say that the other techniques are a bad idea; defense-in-depth is the watchword. But true high-quality security solutions need to address many levels of problems, including both system-level ones and user-facing ones.
Oh... one last thing: Wasn't OpenBSD doing this long before windows?
I believe so. It sounds like the sort of thing they'd do...
"Little does he know, but there is no 'I' in 'Idiot'!"
The biggest security problems with Windows still remain, namely that:
a: compared to it's unix bretheren, Windows still requires administrative privileges for a LOT of common things
b: Microsoft's reliance on proprietary protocols, many of which have a lot of known and probably even more unknown vulnerabilities.
c: security policy on Windows has about 0 coherency, making it really hard to properly secure windows and really easy to accidentally miss something/screw something up. Windows security polices are all over the place, in the registry editor, in the windows security center, in the user/computer policy app(which at least as of xp wasn't searchable, so if you were looking for something and you didn't know EXACTLY where to find it you end up having to look through every single freaking policy. Whats worse is that Windows freely mixes client and server policies, even when the machine isn't a server! Most users get so frustrated and just leave everything open.
I tried to recently secure a Windows XP box after coming from a background of unix(including OS X) and Linux, and I just could not believe how insanely obfuscated Microsoft made everything. What is insanely simple to do in the Unix world takes massive effort to even attempt in the Windows world, if it will even work at all.
I swear Microsoft makes a lot of this stuff pointlessly complicated just so they can persuade more people to take the MCSE exams.
Monstar L
"Apple .. failed to implement fully a security technology that Microsoft perfected nearly three years ago in Windows Vista"
Address space layout randomization is a technique to randomize memory addresses of the base of the code, stack, heap, and libraries. First used by PaX and OpenBSD
I always find articles about OS X security, especially in discussion, painful. First you either have a security expert writing and being translated by a fairly clueless reporter, or you have a clueless reporter writing. In the former case what makes a good article and gets press is usually a security person pointing out weaknesses or flaws in OS X. After all, saying OS X still doesn't have much risk of malware for the average user is like reporting that most GM cars still use gas. It's old info and not news. The other type of article that gets picked up are soft articles about how cool OS X is and how it can't get malware, written for the 90% of the populace that has never used it, but from an uniformed perspective.
Inevitably when either kind of story goes up on Slashdot we see tons of people who know little or nothing about what security is actually implemented in OS X, spouting off one way or the other, usually emotionally defending their favorite OS.
So in this case we have a fairly knowledgeable security expert talking about security in OS X. His sentence about ASLR begins, "One major disappointment in the midst of all these security enhancements..." Based upon what reporters have made of his paper, do any of you know what those security enhancements are? Contrast the expert's conclusion:
While the only true test of security is how effective it is in the real world, on paper it looks like life is now at least a little harder for any potential Mac attackers.
With the title of article linked to:
Apple missed security boat with Snow Leopard, says researcher
That's not to say the article is a filthy lie. It is completely true. Apple did miss the opportunity to improve ASLR for the heap. That's very true and important and disappointing. It's also the only OS X security news most people will hear and that, is misleading. It's not the writer's fault either, they're just writing what's interesting and "news". Writing an article on how Apple's security got moderately better in a number of ways and Macs are still unlikely to have many serious or widespread malware problems going forward for a few years, is not news.
And Apple is not blameless about what press reaches the public either. Apple is pretty quiet about security features in OS X because they don't like to bring up the topic for the general public, except in very generic ways. Their plan seems to be "tell users the security is cool and good and make sure they know they're unlikely to get viruses, but don't confuse them with details. Experts can read the whitepapers." This leaves out the whole middle portion of the spectrum, not security experts but not completely clueless either.
It would be nice to have meaningful discussion on some of the OS X security features, but that might be too much to hope for. What do people think about the sandboxing approach and has anyone noticed any particularly surprising sandboxed services in Leopard? The mixed 32-64 bit thing seems like an interesting choice, with 64 bit application development now motivated by artificially restricting access to some new APIs. Since a lot of the security improvements are tied to 64 bit applications and/or 64 bit processors, do people feel this was an attempt to direct developers for security reasons or just to speed the transition for other reasons? What do people think the other heap protection checksums and protections for 64 bit kernels. Will we transition to 64 bit fast enough so that they will be useful? How about the application signing being tied to the application level firewall? It seems like Apple could have made that a default and really motivated developers to use it, but decided to go in baby steps instead. And why in the world has Apple not created a proper application and update manager that extends to third parties? That seems like a no-brainer from a security and usability perspective.