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ALSR in Vista Gets OEM Push
gr00ve writes "Eweek is reporting that all the major OEMs will enable DEP/NX in their BIOSes by default to allow Address Space Layout Randomization (ASLR), a new security feature in Windows Vista, to work as advertised. ASLR, which is used to randomly arrange the positions of key data areas to block hackers from predicting target addresses, is meant to make Windows Vista more resilient to virus and worm attacks." From the article: "Because most CPUs that ship today support DEP/NX, Howard explained that Vista users on older hardware can use the control panel to manually verify that PCs have DEP enabled. With full support from OEMs, Microsoft is effectively using ASLR to create software diversity within a single operating system, a move that is widely seen as Redmond's attempt to address the monoculture risk. The memory-space randomization technique will block the majority of buffer overflow tricks used in about two-thirds of all worm and virus attacks."
This is a legitimate technique already used by some other high-security OSes (e.g. Open BSD). So it's a legitimately good security measure.
That said, I don't doubt that wanting to better secure their DRM is high on their list of reasons to improve security. That is, they probably want more to secure the machine *from* you than *for* you... While I've certainly had users that the system needed protection from, I still don't like what they're doing with DRM.
Soon, at this rate, you'll either have an unencumbered OS, or what you have won't be fit to call a computer. It'll probably look something more like a high definition TV with popup ads.
Isn't this the same as Linux virtual address randomization that works without BIOS?
Yes, but the NX bit enforcement is part of a larger security push. It just happens that most articles confuse ASLR with NX (or are fuzzy on the details of each) when talking about them both. Part of the confusion is the fact in order for ASLR to be effective, then the NX bit should be enforced. AFAICT, ASLR doesn't actually require NX at all and it's a mistake these "technical journalists" are making.
Basically, Vista adds a bunch of walls to increase security. the NX bit and ASLR are just two separate instances of those walls.
The big news is that even though some OEMs have previously disabled the NX bit in the BIOS (due to software compatibility issues), they've said they'll enable it by default in the future.
I have noticed if DEP is turned on in XP when I look at the folder with all my porn and thumbnails are turned on it causes Explorer to crash. I hope they fix this.
In what way does this prevent FairUse4WM?
f _Buffer_Overflow_Attacks.html
This is a good thing to prevent viruses, without affecting anything else. Buffer overflow attacks need to rely on a known location in memory to jump to, typically kernel32!LoadLibrary/GetProcAddress, which will allow them to dynamically access the rest of the functions they need. Read more here: http://www.windowsecurity.com/articles/Analysis_o
This is 100% completely unrelated to DRM bypass programs, which can actually link to the correct functions. Anyone who mods the parent up has no idea about how windows security or programming works.
It sounds like the parent might (just trying to be generous here) be confusing FairUse4WM with the Apple Fairplay hack tool, which does rely on known offsets within the fairplay module's memory layout. However, even that wouldn't be affacted by this, since an actual properly linked program can still determine the base address it needs.