Software Engineering Institute

Microsoft Data Access Components (MDAC) is a collection of utilities and routines to process requests between databases and network applications. A buffer overflow vulnerability exists in the Remote Data Services (RDS) component of MDAC.

The RDS component provides an intermediary step for a client's request for service from a back-end database which enables the web site to apply business logic to the request.

According to Microsoft's Security Bulletin MS02-065, a routine in the RDS component, specifically the RDS Data Stub function, contains an unchecked buffer. The RDS Data Stub function's purpose is to parse incoming HTTP requests and generate RDS commands. This unchecked buffer could be exploited to cause a heap overflow.

Both web servers and client applications that rely on MDAC are affected. It is recommended that all users of Microsoft Windows 98, Windows 98 SE, Windows ME, Windows NT Windows 4.0, and Windows 2000 apply the patch (Q329414). Windows XP users are not affected as MDAC 2.7, the non-vulnerable version, is installed by default.

A remote attacker could execute arbitrary code with the privileges of the application that processed the request.

In the case of a web server, or other service, this is likely to be SYSTEM, or another account with elevated privileges.

In the case of a client application, or other service, this is the account used to view the web page.

Apply a patch from your vendor.

Microsoft has released a patch (Q329414) and Security Bulletin MS02-065 to address this issue. An end-user version of the document is available at http://www.microsoft.com/security/security_bulletins/ms02-065.asp.

Note that a vulnerable version of the control may be installed on a Windows system that never had the vulnerable control installed prior to the patch being applied. This is due to the fact that the vulnerable ActiveX control is signed by Microsoft and the patch does not set the kill bit for the MDAC control.