US-CERT Says Microsoft's Advice On Downadup Worm Bogus

CWmike writes "Microsoft's advice on disabling Windows' 'Autorun' feature is flawed, the US Computer Emergency Readiness Team (US-CERT) said today, and it leaves users who rely on its guidelines to protect their PCs against the fast-spreading Downadup worm open to attack. US-CERT said in an alert that Microsoft's instructions on turning off Autorun are 'not fully effective' and 'could be considered a vulnerability.' The flaw in Microsoft's guidelines are important at the moment, because the 'Downadup' worm, which has compromised more computers than any other attack in years, can spread through USB devices, such as flash drives and cameras, by taking advantage of Windows' Autorun and Autoplay features."

Comments

Non-Windows User Here

[John Hasler]

Is it really true that you have to edit the registry to turn off autorun? There isn't any clicky? Amazing.

Re:Non-Windows User Here

[lysergic.acid]

that doesn't really provide true protection against all AutoRun attacks.

USB/flash drive-based attacks typically work by creating an autorun.inf file that replaces the default action for that device. by default, XP would simply prompt the user with a list of AutoPlay actions to take (with the AutoRun-specified action selected) when the drive is plugged in. if you "disable" AutoRun, then that menu won't pop-up, but that is arguably more dangerous; the reason being that when the AutoPlay menu pops up the user has a chance to see that an unfamiliar action has been added/selected.

if a computer-savvy user plugs in their iPod/PSP/thumbdrive and the AutoPlay menu shows some strange new action and program icon, they are going to be suspicious. they will likely select the "Open folder to view files using Windows Explorer" action to browse the volume and probably detect the malware and autorun.inf file.

now, a typical scenario when AutoPlay is disabled is that a user will plug in an infected flash drive, open up My Computer, and proceed to double-click on the removable volume to open it for browsing. however, whether or not AutoPlay/AutoRun is enabled, an autorun.inf file can replace the default action for that volume. and this time the user has absolutely no warning (unless the malware author is dumb enough to replace the volume's icon and advertise the presence of the virus). i mean, how often do you actually right-click on a volume to select "Open" from the context menu or to check its default action? most people are in the habit of simply double-clicking on a drive icon to browse its contents.

then there's the matter of dual-filesystem flash drives. because Microsoft places the interests of the RIAA ahead of the interests of their customers, they've used AutoRun to implement a rather dangerous DRM mechanism. if CDFS is detected on any removable volume, Windows automatically assumes that it is a protected CD and will launch any program specified by autorun.inf. this functionality will work whether or not you have configured Windows to allow AutoRun or not, and you cannot bypass it by holding down the "shift" key. but that can only be expected when you have DRM that's designed to "protect" the system from its user/owner.

Re:Windows itself is a vulnerability.

[hairyfeet]

Or you could, oh I don't know, not let morons near your computer? I'm typing this on a Win2K pro machine that has been hooked to the net and running non stop for almost 9 years. In that time I have gotten zero, zip, nada, squat on the virus front. Why? Because I don't let morons on this machine, that's why.

As a PC repairman I have noticed the PEBKAC problems with Windows can nearly always be traced to one of three types. One, the "anything my friend (insert name of girlfriend) sends me has to be okay." Those can usually be dealt with by installing a decent AV and having them use webmail instead of OE. Two, the "I will click on anything that'll get me teh hot lesbos!" guy. You can usually cut down on his rate of pwnage by giving a copy of Firefox loaded with bookmarks for places like Youporn and Redtube. And three, the "I click on everything I loads off the Kazaa!" types. These are usually dumbass teenagers looking for the latest horrible pop drivel and instead clicking on "lousy_tune.mp3.exe" thinking it is their pop drivel. Putting them in a limited user account and putting a good AV to scan whatever folder they are downloading crap to usually does the trick.

The point is blaming Windows for morons is like blaming the SUV manufacturers when some woman plows through a family of five because she ran a redlight while playing with her cell phone. Stupid people will find a way to break stuff, hence why we call them stupid. If you put these types on OSX or Linux they would break just as much as they do on Windows. They would just be loading "Hot_Pron_codec.dmg" or "killer_tune.sh" instead of an .exe. It all comes back to the dancing bunny problem. The best we tech guys can do is educate where we can, and take steps like the ones listed above to minimize the damage they can do. Because I don't care which OS you give them PEBKAC problems will NEVER go away. After all this problem wouldn't exist in the first place if folks had actually bothered applying the patch the MSFT released in OCTOBER. Just further proof that they ain't exactly brain trusts we are talking about here.