RE: Question: Buffer Overrun in Microsoft Data Access Components Coul d Lead to Code Execution (Q329414)

From: Brad Bemis <Brad.Bemis(at)airborne.com>
Date: Wed Nov 27 2002 - 11:51:27 EST

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I am a little leery about installing MDAC on client systems that do not require the full suite of services it provides.

We have been updating our servers to MDAC 2.7, but rolling out the patch via logon/shutdown scripts to our client base. I am not entirely happy about the inherent flaw in this particular patch, but as I understand it, the flaw revolves around the new component control for RDS being replace by a pre-patched version.

Has anybody taken a good hard look at what discernable changes take place when the pre-patched version is reintroduced?

I'd be interested in the possibility of identifying specific elements of the control that can be tested by a script to determine which version is currently active and reapplying the patch if indeed the old control component has been reintroduced.

Does anyone have any thoughts on this?

• - Brad Bemis
• -----Original Message----- From: Harris, Ken [mailto:KHarris@HIPUSA.com] Sent: Tuesday, November 26, 2002 12:16 PM To: 'Kolde, Jennifer E.'; 'focus-ms@securityfocus.com' Subject: RE: Question: Buffer Overrun in Microsoft Data Access Components Coul d Lead to Code Execution (Q329414)

Hello,

Thanks to all on focus-ms who replied, very good information indeed. It looks like the best practice is to upgrade across the board to MDAC 2.7 (with proper testing) /unless/ there is a known inoperability requiring 2.6,
in which case the patch is our best (albeit weak) hope.

Thanks again for your help,

Ken Harris

• -----Original Message----- From: Kolde, Jennifer E. [mailto:jkolde@nosc.mil] Sent: Tuesday, November 26, 2002 1:21 PM To: Harris, Ken; 'focus-ms@securityfocus.com' Subject: RE: Question: Buffer Overrun in Microsoft Data Access Components Coul d Lead to Code Execution (Q329414)

Hello Ken,

Sorry, trying again minus the digital signature.

Microsoft also (quietly) lists upgrading to MDAC 2.7 as another fix. The information in the security bulletin is a bit confusing when you try to figure out just what is going on and where the vulnerability lies. The way I
read it, the problem lies both the version of MDAC used AND a specific ActiveX control that is vulnerable. You are correct that even if you patch your current version of MDAC, the vulnerable ActiveX control could still be introduced.

MDAC 2.7 is not vulnerable to the problem according to Microsoft, so if you upgrade to 2.7, the ActiveX issue becomes moot.

A possible concern is that, because MDAC brokers your database requests, the
upgrade may affect your application based on any differences between the older MDAC components and 2.7. I'm not a database guru (IANADBG???) so you'd have to research/test this on your own.

MDAC can be downloaded from http://www.microsoft.com/data/, which also includes documentation / changelogs for different versions. I did install MDAC 2.7 on a Win2K Server with no ill effects, but the Server is not doing anything specifically database-related.

Regards,
Jennifer

• -----Original Message----- From: Harris, Ken [mailto:KHarris@HIPUSA.com] Sent: Friday, November 22, 2002 2:39 PM To: 'focus-ms@securityfocus.com' Subject: Question: Buffer Overrun in Microsoft Data Access Components Coul d Lead to Code Execution (Q329414)

Hello all on focus-ms,

Was wondering if anyone had figured out the best practice fix to the security flaw described here:

http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/ bulletin/MS02-065.asp

The reason I ask is that Microsoft does not seem to show much confidence in this patch; e.g. in the Caveats section, it is implied that if a webpage references the older, pre-patch RDS control, dependent upon the IE security settings they will either be prompted to install the control, or it will be installed silently if Microsoft is added to the Trusted Publishers list.

We happen to have a mission-critical custom webapp used internally which does use RDS, and is in the Trusted Sites zone on our workstations. However,
I can't guarantee that the developers of this solution will get around to patching the server on which this runs, or changing the references in the ASP pages. Microsoft is NOT in the Trusted Publishers list on our workstation build, although there is nothing keeping our users from clicking
"Always trust content from Microsoft".

Am I right in assuming that even if we deploy the patch to our workstations,
unless the patch is also applied to the webapp and the code is changed, the vulnerable control could be reinstalled and the workstation would be again vulnerable to this attack from a malicious website? Is there a better option? The client/server nature of this vulnerability makes me think that we may see a worm written to exploit it soon.

Thanks in advance.

Regards,

Ken Harris

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Received on Thu Nov 28 15:42:22 2002