Microsoft Issues Patch for 'Critical' Windows Security Flaw
What Is It?Microsoft has issued a software patch for what it described as a "critical" new security vulnerability affecting most versions of Windows and certain versions of the Internet Explorer Web browser.
Affected are certain versions of Windows NT, Windows 2000, and Windows Me, Microsoft said. Other versions of Windows may also be vulnerable. However, Microsoft said Windows XP users are not affected and need take no action.
Systems running Internet Explorer versions 5.01, 5.5, and 6.0 are also affected by the new vulnerability, Microsoft said.
A free downloadable patch is available now. Microsoft describes the flaw in security bulletin MS02-065.
How Bad Is It?The vulnerability involves what's known as an "unchecked buffer" in the Remote Data Services (RDS) component of MDAC. The faulty code is in a function called the RDS Data Stub, which is used to pull information from incoming HTTP requests and create RDS commands, according to Microsoft.
An attacker could exploit the security weakness by sending an improperly formatted HTTP request to the Data Stub that contained extra data. The surplus would cause the buffer to overflow, and in the process would place and run the attacker's data on the victim's PC.
"What makes it really quite dangerous is that it can be easily added to a worm," McClure said. "It's very much in line with Code Red and Nimda because of the attack vectors and the ways that it attacks. But with this vulnerability both the server and client component can be attacked, as opposed to Code Red and Nimda, which basically exploited server-based vulnerabilities and didn't take advantage of a browser based vulnerability like this."