Threat Level: green Handler on Duty: Russ McRee

SANS ISC: MS10-070 OOB Patch for ASP.NET vulnerability - Internet Security | DShield SANS ISC InfoSec Forums


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MS10-070 OOB Patch for ASP.NET vulnerability

Microsoft Bulletin MS10-070 has been released. An update is now available that addresses the ASP.NET "information disclosure" vulnerability (CVE-2010-3332) that we reported on earlier 

The core piece in the advisory is probably in the section that reads

"In Microsoft .NET Framework 3.5 Service Pack 1 and above, this vulnerability can be used by an attacker to retrieve the contents of any file within the ASP.NET application, including web.config"

Translated, this means that the vulnerability undermines basic web application security. I suspect that online shops and such might rate the risk that "an attacker can read any file" on their web application server a bit higher than just "important".

According to the bulletin, MSFT are aware of "active attacks".

In combination, this sure sounds like PATCH NOW! to me.

Daniel

367 Posts
ISC Handler
yeah, like Microsoft would release an "important" patch out of band...
Ken

40 Posts
My favorite part of the bulletin. "Why are the updates only available from the Microsoft Download Center? Due to the active attacks currently exploiting this vulnerability and the severity of potential loss of data, we are releasing these updates to the Microsoft Download Center so that customers can begin updating their systems as soon as possible. These updates will also be provided through our other standard distribution methods once testing has been completed to ensure distribution will be successful through these channels." In a nutshell, there is no support yet for using DSUW, WU, MU, SMS ITMU, or anything else to deploy these patches. It's not a big deal for workstations, since you shouldn't be running IIS on workstations and should be shields up 24x7 even on your internal LAN on your workstations. And for servers, you can always get something pushed out to the boxes you know are running ASP.NET.
Anonymous
so, is this officially "PATCH NOW" or not??
Anonymous
@dt, yes it is. You mileage might vary though - the patch is only available through Download Center for now, and not yet via the automated channels. But if you have a valuable internet facing server that is affected by the vulnerability, yes, *test* and then patch asap.
Daniel

367 Posts
ISC Handler
27 different downloads, targeting .Net 1.1 through 4.0 on x86, x64, and IA64. Download Center ridiculousness. And you can’t do a rolling upgrade on a web farm! The patch changes the length of encrypted strings, especially in WebResource.axd files, so unpatched machines can’t concurrently run on the same farm as patched machines.
Joey

18 Posts
http://isc.sans.edu/images/status.gif is still green...
Ken

40 Posts
@Ken, if you move away from the PC fast enough, the doppler effect will make it look like yellow. OKOK, you're right, we're working on it :)
Daniel

367 Posts
ISC Handler
@Joey
Where did you get your information about needing to push out the patch all at once or having your farm break? Anyone else know if this is true?.. Trying to decided if should implement this patch or wait for reports of broken farms.
Daniel
2 Posts
Is this still considered a patch now if the two workarounds are in place?
sedavel

2 Posts
Is this still considered a patch now if the two workarounds are in place?
sedavel

2 Posts
@arom, see ScottGu's blog for the webfarm info -- http://weblogs.asp.net/scottgu/archive/2010/09/28/asp-net-security-update-now-available.aspx
Paul

44 Posts
@Paul
Thank you for the link.
Paul
2 Posts
@dave@work: probably not, or not completely (also see ScottGu's blog). One of the authors of the attack, Thai Duong, wrote (9:21 PM Sep 25th at http://twitter.com/thaidn/):
"Another video may prove it all, but I'm tired. So believe it or not, Microsoft workarounds can't prevent the attack. Ask them for the patch!"

In http://netifera.com/research/poet//PaddingOraclesEverywhereEkoparty2010.pdf Thai Duong and Juliano Rizzo wrote:
"POET -> remote code execution -> Cesar’s Token Kidnapping -> ROOT privilege on Windows"

The POET version that supposedly does this, has not yet been released, but if it is true then Microsoft flagging this vuln as "Important" seems not entirely appropriate to me.

Cesar Cerrudo's Token Kidnapping Revenge (privilege escalations and some fixes) are described in this document: http://www.argeniss.com/research/TokenKidnappingRevengePaper.pdf

Hopefully MS10-070 properly fixes this ASP.NET vulnerability...
Erik van Straten

122 Posts
Bit confused around Server 2008 w/ .net 1.1 sp1.

According to microsoft you need to apply kb2416447

And it says that this is supported on the download page:

http://www.microsoft.com/downloads/en/details.aspx?familyid=a7990e61-21fd-4942-9dfe-af7961cb0282&displaylang=en

But it won't run on 2008, and the kb page itself ( http://support.microsoft.com/?kbid=2416447 )has no mention of 2008 support!

Also, the filename says x86, no clarity if there is a seperate x64 version or not.



Erik van Straten
1 Posts
Microsoft should sue Jualiano Rizzo and Ekoparty.
Anonymous
@zonky That should be the right download, so not sure why it won't run for you. There won't be a seperate x64 selection for you since .Net 1.1 is 32 bit only and runs on WOW on x64 and IA64. MS probably screwed up the installer package - I'd contact support.
Joey

18 Posts
Question, It appears some of our Development systems have more then one version of framework installed, does each respective patch need to be installed?
Anonymous
@Davef. Dave. I haven't got a system handy to confirm, but considering the files are different for each flavour of .net I would have to say "yes you do".
Mark

391 Posts
ISC Handler
I have published a writeup from an security operations guy perspective on http://cupfighter.net
Mark
10 Posts
If you have any data in a web shop inside the webroot that is not safe for customers to see you have a problem before this bug was discovered.
If you use database passwords, then you also has a problem already that needs to be fixed. Windows Integrated authentication has been Microsofts recommendation for 10 years by now (Since SQL Server 2000).

I would say, that this is a patch now only for bad websites. Well designed websites does not have any secret information inside webroot, does not rely on client side data being untampered and information disclosure is only of public available information anyway.

Viewstate is IMHO not any better than a form or cookie where the client can change data at his will. If the stake is high enough, the encryption can always be broken.
Povl H.

71 Posts

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