Exploit for unpatched IE vuln fuels hacker fears
John Leyden, The Register 2005-08-19

Microsoft is investigating an IE security bug amid fears that a hacker attack based on the vulnerability is imminent. A flaw in Microsoft DDS Library Shape Control COM object (msdds.dll) is at the centre of the security flap.

Security researchers warn that msdss.dll might be called from a webpage loaded by Internet Explorer and crash in such a way that allows hackers to inject potentially hostile code into vulnerable systems. That's because IE attempts to load COM objects found on a web page as ActiveX controls, as is the case with msdds.dll. A programming object is not supposed to be used in this way. So hackers might be able to take control of systems by tricking users into visiting a maliciously constructed web site. US-CERT warns that exploit code to do this is already available but Microsoft said it's not aware of any attacks.

No patch is available but Microsoft has posted a bulletin detailing possible workarounds. These include disabling ActiveX controls, setting the kill bit for msdds.dll and unregistering msdds.dll. Use of an alternative browser (such as Firefox, Opera) is also an option.

Msdds.dll is a .NET component not loaded onto Windows by default. But the COM object is reportedly installed as part of the following products: Microsoft Office XP, Microsoft Visual Studio .NET 2002, Microsoft Visual Studio .NET 2003 and Microsoft Office Professional 2003. That means there'll be a large number of potentially vulnerable systems.

The SANS Institute's Internet Storm Centre has upped its alert status to yellow because of concerns that "widespread malicious use of this vulnerability is imminent". The vulnerability was publicly disclosed by FrSIRT based on information it received from an anonymous source. Microsoft has criticised the "irresponsible" way the vulnerability came to light. ®