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Vista's Security Rendered Completely Useless
Posted by
kdawson
on Fri Aug 08, 2008 07:08 AM
from the bypassing-memory-protection-safeguards dept.
from the bypassing-memory-protection-safeguards dept.
scribbles89 sends in a story that originally ran in SearchSecurity; it sounds like it could be a game-changer. "While this may seem like any standard security hole, other researchers say that the work is a major breakthrough and there is very little that Microsoft can do to fix the problems. These attacks work differently than other security exploits, as they aren't based on any new Windows vulnerabilities, but instead take advantage of the way Microsoft chose to guard Vista's fundamental architecture. According to Dino Dai Zovi..., 'the genius of this is that it's completely reusable. They have attacks that let them load chosen content to a chosen location with chosen permissions. That's completely game over.'" Update: 08/08 14:23 GMT by KD : Changed the link, as the story first linked had been lifted without attribution.
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Details... (Score:5, Insightful)
Too bad it doesn't explain what they actually did and just says "ooo, this is really bad". It'd be interesting to see a description, and see if other systems with similar protections are vulnerable.
Re:Details... (Score:5, Insightful)
These techniques are being seen as an advance that many in the security community say will have far-reaching implications not only for Microsoft, but also on how the entire technology industry thinks about attacks. Expect to be hearing more about this in the near future and possibly being faced with the prospect of your "secure" server being stripped completely naked of all its protection.
From this paragraph it sure sounds like the author of the article hasn't got a clue.
Parent
Re:Details... (Score:5, Insightful)
Exactly. It's saber rattling. Sounds like nothing more.
Furthermore, I love how silly some people here can be. The article says:
But somehow this is a Vista security issue?
Please. Many here on this site, and many articles posted here, have a bias. There's nothing wrong with that, most things in life have a bias in some way.
But there's a difference between "bias" and "intellectual dishonesty."
This is the latter.
Parent
Re:Details... (Score:5, Informative)
variety of scripting languages, such as Java, ActiveX and even .NET objects.
None of those things listed is a scripting language...
Parent
Re:Details... (Score:5, Informative)
It clearly means any environment which results in a compilation stage within the browser:
* Java - JIT .NET - JIT
*
* JavaScript - JIT on some browsers now
Why? Because they compile into executable code within a browser. Clearly the compiler/JIT/browser should sandbox these. But to compile code into memory, you need to disabled the NX bit check... that's one security mechanism bypassed. And I presume that address randomisation doesn't work for these JITs either. Yet.
Parent
Re:Details... (Score:5, Insightful)
I usually like to pick a nit as much as anyone, but if one reads "scripting language" as "environment in which script can run in a browser", which is not that much of a stretch, it makes perfect sense.
Parent
Re:Details... (Score:5, Funny)
Parent
Re:Details... (Score:5, Insightful)
Parent
Re:Details... (Score:5, Insightful)
Every time an exploit occurs, people start blabbering about "correctly configured" machines, completely missing the point. What is really important is this: does it work on an out-of-the-box Vista or not?
Parent
Re:Details... (Score:5, Informative)
While you have a point, I'd just like to point out that out-of-the-box IE is in a sandbox in Vista. Frankly, I don't even know how to run it otherwise.
Parent
Re:Details... (Score:5, Insightful)
"Properly configured" in the case of IE's sandbox means "I didn't turn off UAC". So, no, an attack that's stopped by IE sandboxing does not work on out-of-the-box Vista. It would only work on the sort of Neowin-reading "power users" who turn off security features to gain (perceived) speed and convenience.
Parent
Re:Details... (Score:5, Informative)
More details would have been nice.
Well, ok.
http://taossa.com/archive/bh08sotirovdowd.pdf [taossa.com]
Here's some code for ya too
http://taossa.com/archive/bh08sotirovdowdcode.zip [taossa.com]
Enjoy!
Parent
Re:Details... (Score:5, Informative)
Parent's linked PDF is:
Bypassing Browser Memory Protections
Setting back browser security by 10 years
Alexander Sotirov
Mark Dowd
it apparently is the discussed paper. Mod parent up please, it's +1 very interesting.
Parent
Re:Details... (Score:5, Funny)
I read it and now my system IE is full of toolbars. Oh shi
Parent
Re:Details... (Score:5, Informative)
They also don't point out whether this breaks out of the IE sandbox or not. This makes a big difference, as if they can't break out of the sandbox, it makes any attack fairly useless on a correctly configured machine using IE. More details would have been nice.
From TFA:
By taking advantage of the way that browsers, specifically Internet Explorer, handle active scripting and .NET objects, the pair have been able to load essentially whatever content they want into a location of their choice on a user's machine.
From /. Summary:
They have attacks that let them load chosen content to a chosen location with chosen permissions.
I think it's pretty clear that it is out of the sandbox and has full access to the backyard and house, regardless of how Vista is configured.
Parent
Re:Details... (Score:5, Funny)
your running kernel...
"Excuse me, is your kernel running?"
"Yes..."
"Well then you'd better go catch it before it trips over your address space layout randomization and skins its knees on the data execution prevention!"
Parent
Re:Details... (Score:5, Interesting)
In the days of the Web there is a rule that if someone tells the press before they publish the paper, they are full of it. They haven't told Microsoft, so they can't even claim that they are not releasing the details to allow for a fix.
CF all those 'studies' that 'prove' porn is bad or watching TV turns kids into Martians or whatever. Every time that stuff hits the press the paper is 'to be published' which is a good way to prevent opponents getting in a response.
Parent
Re:Details... (Score:5, Insightful)
In the days of the Web there is a rule that if someone tells the press before they publish the paper, they are full of it. They haven't told Microsoft, so they can't even claim that they are not releasing the details to allow for a fix.
They're presenting their findings at a black hat conference this week. What makes you think they have any motivation to help MS fix it beforehand? Did it ever occur to you, as people who break security systems they think impede their own and other peoples freedom, they might, just might, have a strong motive to punish anyone who installed it and drive them off Vista?
Parent
Re:Details... (Score:5, Insightful)
Parent
Re:Details... (Score:5, Insightful)
You want to punish people for their choice of OS? That's freaking hysterical. I think you need a little perspective realignment...
Parent
Re:Details... (Score:5, Funny)
You want to punish people for their choice of OS? That's freaking hysterical. I think you need a little perspective realignment...
Especially considering the fact that if you run microsloth the punishment is the crime.
Parent
Re:Details... (Score:5, Funny)
Parent
An incredibly worrying response from Microsoft (Score:5, Interesting)
From TFA:
"While Microsoft hasn't officially responded to the findings, Mike Reavey, group manager of the Microsoft Security Response Center, said the company has been aware of the research and is very interested to see it once it has been made public."
So, Microsoft is
a.) Not currently aware of the details of the exploit and
b.) Doesn't plan (or, apparently, want) to GET the details until the details are PUBLISHED.
Apparently, Microsoft's "Security Response Center" has no idea that they have a window of opportunity to fix the problem BEFORE the details are in the wild. Why would we want that? Nah, we don't need to be pressing for details. We'll figure it out when our customers start screaming about exploits.
I've thought MS was somewhat incompetent on security, but this is mind boggling.
Parent
Re:Details... (Score:5, Insightful)
I'm sure I'm not the only one who remembers running some little script [slashdot.org] with normal user privileges, and suddenly seeing the prompt change from
user@computer:~$
to
root@computer:~#
And, well, that had been around forever, apparently. And, well, it was fixed the next day.
The moral? Horrendous, gaping security holes do exist, and are found from time to time. And they get fixed (faster in FOSS than Windows, but they still get fixed). Of course, some OSs are more equal than others when it comes to general security and user-centric design, but I just can't believe for a minute that this is some life-shattering, end of the world event for Microsoft.
Parent
Re:Details... (Score:5, Funny)
PS1="root@computer:~#"
export PS1
# Pwned
Parent
Re:Details... (Score:5, Interesting)
OpenBSD uses ksh. Bash isn't installed by default, and iirc goes into /usr. In any case, scripts should only assume that /bin/sh is available.
Parent
Re:Details... (Score:5, Insightful)
Extraordinary claims require extraordinary proof. The linked article provides... vagueness. It mentions that used a browser (which one?) And that it has something to do with defeating the NX bit. I'm guessing that it's not nearly as severe as this article's hyperbole makes it seem.
Parent
Re:Details... (Score:5, Funny)
Windows vulnerabilities are extraordinary?
I'll have some of what you're drinking, please.
Parent
Re:Details... (Score:5, Insightful)
which makes it extraordinary.
Parent
Yeah, wasn't there some important necessity... (Score:5, Insightful)
Something about "Big Claims" needing "Big Evidence"?
The "rah rah" quotes from the reporter make it sound like bullshit, even if it weren't. Without even the barest sensible explanation about what was done here, this is a non-story.
Parent
Re:Yeah, wasn't there some important necessity... (Score:5, Interesting)
TFA does imply that the exploit takes advantage of an assumption at the OS level that .NET objects are automatically safe, and gives them the same privileges as the browser itself. It also says that the exploit takes advantage of a multi-homed attack using different scripting methods. Given that information, I'd venture a wild-assed guess that the exploit most likely uses JAVA and/or ActiveX to load a downloaded/forged .NET object which in turn loads arbitrary code as described.
If there's truth to the assumption about .NET objects, then it's a monumentally stupid decision on Microsoft's behalf. But there is a (temporary) fix that can be patched into the OS by requiring a signature. Yes, those can be forged. Yes, it's a stop-gap measure. But if you require authentication from online servers (remember, this is a drive-by online exploit, so it's safe to assume that anybody who needs to validate a signature like this has Internet access), then it is an improvement until it can be fixed properly.
Parent
Marketing opportunity (Score:5, Funny)
Microsoft has reacted to this security exposure by launching a new version that puts the OS out of reach and is guaranteed attack-proof: Vista for Vacuums.
Game Over? I doubt it (Score:5, Insightful)
First of all, the hack takes advantage of the way Internet Explorer handles scripting languages, implying that Firefox/Safari/Opera users are safe. Second, I can run most Windows code on my Linux machine via Wine. If Wine doesn't have this security hole (or even XP for that matter) then its perfectly reasonable to assume that a rewrite of the affected portions of Vista will provide the fix.
To say that it's broken and can't be fixed is as much of a sure thing as saying it's secure and can't be hacked.
active scripting (Score:5, Insightful)
you might know it better as ActiveX, available nowhere outside of IE. "other browsers" in this case refers only to browsers which are simply IE shells.
Parent
Article Text (Score:5, Informative)
This week at the Black Hat Security Conference two security researchers will discuss their findings which could completely bring Windows Vista to its knees.
Mark Dowd of IBM Internet Security Systems (ISS) and Alexander Sotirov, of VMware Inc. have discovered a technique that can be used to bypass all memory protection safeguards that Microsoft built into Windows Vista. These new methods have been used to get around Vista's Address Space Layout Randomization (ASLR), Data Execution Prevention (DEP) and other protections by loading malicious content through an active web browser. The researchers were able to load whatever content they wanted into any location they wished on a user's machine using a variety of scripting languages, such as Java, ActiveX and even .NET objects. This feat was achieved by taking advantage of the way that Internet Explorer (and other browsers) handle active scripting in the Operating System.
While this may seem like any standard security hole, other researchers say that the work is a major breakthrough and there is very little that Microsoft can do to fix the problems. These attacks work differently than other security exploits, as they aren't based on any new Windows vulnerabilities, but instead take advantage of the way Microsoft chose to guard Vista's fundamental architecture. According to Dino Dai Zovi, a popular security researcher, "the genius of this is that it's completely reusable. They have attacks that let them load chosen content to a chosen location with chosen permissions. That's completely game over."
According to Microsoft, many of the defenses added to Windows Vista (and Windows Server 2008) were added to stop all host-based attacks. For example, ASLR is meant to stop attackers from predicting key memory addresses by randomly moving a process' stack, heap and libraries. While this technique is very useful against memory corruption attacks, it would be rendered useless against Dowd and Sotirov's new method. "This stuff just takes a knife to a large part of the security mesh Microsoft built into Vista," said Dai Zovi. "If you think about the fact that .NET loads DLLs into the browser itself and then Microsoft assumes they're safe because they're .NET objects, you see that Microsoft didn't think about the idea that these could be used as stepping stones for other attacks. This is a real tour de force."
While Microsoft hasn't officially responded to the findings, Mike Reavey, group manager of the Microsoft Security Response Center, said the company has been aware of the research and is very interested to see it once it has been made public. It currently isn't known whether these exploits can be used against older Microsoft Operating Systems, such as Windows XP and Windows Server 2003, but since these techniques do not rely on any one specific vulnerability, Zovi believes that we may suddenly see many similar techniques applied to other platforms or environments. "This is not insanely technical. These two guys are capable of the really low-level technical attacks, but this is simple and reusable," Dai Zovi said. "I definitely think this will get reused soon."
These techniques are being seen as an advance that many in the security community say will have far-reaching implications not only for Microsoft, but also on how the entire technology industry thinks about attacks. Expect to be hearing more about this in the near future and possibly being faced with the prospect of your "secure" server being stripped completely naked of all its protection.
Sceptically speaking... (Score:5, Insightful)
Save your Microsoft bashing for the unlikely possibility that this is even half the exploit as Dowd and Sotirov are claiming.
Their Blackhat presentation has a great name... (Score:5, Informative)
How To Impress Girls With Browser Memory Protection Bypasses [blackhat.com].
Game over? Sounds more like "Gentlemen, start your engines."
Well, OK, then. Security (Score:5, Funny)
But what about all the _other_ great things about Vista? Like......ummm, you know.
Not surprised (Score:5, Insightful)
it is only a matter of time for any malicious third party to figure out your elaborate access scheme and get control of people's computers. because if you can do it, others can do it too.
Hmm... (Score:5, Interesting)
Looks to me more like a .NET and IE design flaw that could be easily fixed, than what this article is making it out to be. ABSOLUTE worst case is that it requires better authentication of the system's own code, which... shit, isn't that already part of Vista's security model? Just expand the scope. (Granted, THAT could break stuff.)
And, there's even a quick and dirty fix Microsoft could do, albeit at a possible extreme performance hit.
Sandbox .NET apps, don't trust any of the framework.
It could break OLE horribly, but not if they do it right - and how much is old-school OLE used anyway? And, for ActiveX plugins that are also used as standalone apps (such as Adobe Reader,) just fire up a second copy of the process in the sandbox.
Not a real problem (Score:5, Funny)
Hackers will get so frustrated with the repeated, "Are you sure you want root privileges?" dialogs that they'll give up.
Dai Zovi is Completely Wrong (Score:5, Informative)
Internet Explorer (or any Common Language Runtime host) is subject to .NET's Code Access Security model. Assemblies from untrusted locations, like the Internet Zone get a very restricted set of permissions unless there is an explicit CAS policy in place to give said assemblies more permission via some form of evidence (usually a strong name or x.509 certificate).
Security is applied based on the caller, so you can't load an untrusted assembly and elevate its priviledges by simply calling a method on a trusted component on the local machine. This is not enforced by IE (or any other host) but by the runtime itself. In order to get full trust you have to get a policy in place or somehow trick the host into thinking the source is a trusted location.
Given his completely false assertion that "Microsoft assumes they're safe because they're .NET objects", you should discount everything else he has to say because he clearly has no reservations about making strong assertions about things he doesn't understand.
Neowin Plagiarists? (Score:5, Interesting)
Too funny, not on is this article blog spam, it's plagiarised blog spam!
This comment is at the bottom of their board.
nice
This is not strictly Microsoft's fault... (Score:5, Interesting)
... although a large part of the blame does rest with them.
The real problem with Windows security is that there are LOTS of programs out there that will not run unless the user is an administrator.
This is a relic of the old MS-DOS mindset, where any program could put anything anywhere on the disk that it wanted to, or mess with anything in memory that it wanted to. This attitude moved along with the coders to the Windows platform, so you have programs that try to put log files in the same directory as the executable instead of in the user's home directory. When the user calls support and asks how to fix this, the fastest way to get them off the phone is to say "run as administrator", so that's what happens.
Microsoft's part of problem is that rather than saying "Don't do that - fix your program so it can run under a normal user account", they made it so you can run as administrator, and then tried to intercept user actions that might hose things up.
Clever, but not devastating (Score:5, Interesting)
This presentation was how to get around features that try to prevent exploitation of memory safety bugs [squarefree.com] in applications. The intent of these features is that even if you find a buffer overflow in Notepad, you won't be able to do anything other than make Notepad crash.
These compiler and OS features try to disrupt the exploitation of memory safety bugs in various ways. Some work by detecting memory corruption (e.g. checking "stack cookies" before returning from a function that uses a string buffer). Others work by making it hard for an attacker to place shell code at a predictable memory address (e.g. DEP [wikipedia.org] or ASLR [wikipedia.org]).
The presenters demonstrated clever ways to get around many of these protections, but by showing how tricky it was to do so, they actually showed how effective the protections are against applications other than web browsers. To create memory that was both under their control and marked as executable, they had to take advantage of weird behavior of .NET controls (IE-only), Flash, and Java applets. The .NET control behavior looked like a bug Microsoft could fix without breaking any controls, since it involved lying about the .NET version a control was created for. The Flash behavior (a missing compiler flag) is already being fixed. The Java issue is that all Java memory is marked as executable; I don't know how hard that would be to fix, but I imagine most Slashdot users don't have to worry about this because they have already disabled Java applets.
I don't think this is devastating even to web browsers. I work on Firefox, and I know these protections haven't made us complacent about looking for and fixing memory safety bugs. Meanwhile, not all web browser security holes are memory safety bugs, so most browsers all have automatic update systems in place to ensure users receive new versions quickly.
(I attended the Black Hat presentation but did not read the full paper [taossa.com].)
Re:".NET loads DLLs into the browser itself..." (Score:5, Insightful)
So in other words, like 80+% of the other exploits on web, the exploit only works if you use Internet Explorer?
From TFA:
This feat was achieved by taking advantage of the way that Internet Explorer (and other browsers) handle active scripting in the Operating System. (emphasis added)
Parent
Re:".NET loads DLLs into the browser itself..." (Score:5, Informative)
As far as I'm aware, other browsers* don't allow "active scripting" to access the operating system unless a plug-in has been installed to do so (such as Java or Flash, and those have their own built-in restrictions).
* "other browsers" meaning ones that aren't IE or re-branded versions of IE.
Parent
Re:Before the Slashdotters rip this article apart. (Score:5, Interesting)
I suspect you're right. Reading the article, it sounds like they have a way of using browser plugins as a way to get around the address space randomization features in Vista. That's a big deal, and it really might be as hard to patch as they claim. But address space randomization was never a silver bullet and even without it, all they've done is put is back to a Windows XP world.
What would be interesting is if they can extend the attack to Linux, which also does a certain amount of randomization. If they can do that, then they've got a reusable, general purpose attack. But, as it stands, it certainly doesn't sound like anything too new. People have been attacking Flash, ActiveX, Java applets, and other plugins for years.
Parent
Re:Vista "Shatter" Attack? (Score:5, Interesting)
It definitely sounds like a shatter attack [wikipedia.org], but I thought that Vista's new security model was supposed to prevent this. (No, not being facetious, I really thought this).
Parent
Re:I sense a new alert message in your future... (Score:5, Insightful)
And that will be extremely effective, right up until Joe Sixpack says, "Well if I say no, I can't get my porn." and clicks Yes.
Parent