Security Intelligence Operations

An unauthenticated, remote attacker could exploit this vulnerability to cause Internet Explorer to terminate, or execute arbitrary code with the privileges of the user. The targeted user's privileges will determine the level of system compromise. If an affected system grants the user Administrator privileges, the attacker could take complete control of the system.

This vulnerability exists due to improper IObjectSafety properties on affected ActiveX controls. Although the affected control is not marked safe for scripting, the library improperly implements IObjectSafety restrictions, allowing an attacker to load this control within Internet Explorer.

The tblinf32.dll library, or the similar vstlbinf.dll library exist as part of Microsoft Visual Basic. The TypeLibInfoFromFile() function that is contained within either library accepts paths to remote locations as input. An unauthenticated, remote attacker could exploit this vulnerability by loading the affected control within a browser and supplying the control with a path to a remote, malicious file as part of a web page. By directing the control to a remote location, the attacker could cause a user's browser to load a malicious file, corrupting system memory. The resulting memory corruption could allow an attacker to cause Internet Explorer to terminate, or execute arbitrary code with the privileges of the user who launched the affected application.

Administrators are advised to apply the appropriate updates.

Users are advised not to open e-mail from untrusted sources.

Users are advised to run applications with the lowest necessary privileges.

Users are advised not to follow unsolicited links. Users should verify the authenticity of an unexpected link from a trusted source prior to following the link.

Administrators may consider disabling ActiveX.

Administrators may consider disabling the vulnerable ActiveX controls by enabling their kill bits in the Windows Registry via the following CLSIDs:

{8B217746-717D-11CE-AB5B-D41203C10000}
{8B217752-717D-11CE-AB5B-D41203C10000}
{8B21775E-717D-11CE-AB5B-D41203C10000}

Microsoft has released updated software at the following links:

• Microsoft Internet Explorer 5.01 SP4 on Windows 2000 SP4
• Microsoft Internet Explorer 6 SP1 on Windows 2000 SP4
• Microsoft Internet Explorer 6 for Windows XP SP2
• Microsoft Internet Explorer 6 for Windows XP Professional x64 Edition SP2 or prior
• Microsoft Internet Explorer 6 for Windows Server 2003 SP1 or SP2
• Microsoft Internet Explorer 6 for Windows Server 2003 x64 Edition SP2 or prior
• Microsoft Internet Explorer 6 for Windows Server 2003 SP1 or SP2 for Itanium-based Systems
• Windows Internet Explorer 7 for Windows XP SP2
• Windows Internet Explorer 7 for Windows XP Professional x64 SP2 and prior
• Windows Internet Explorer 7 for Windows Server 2003 SP1 and SP2
• Windows Internet Explorer 7 for Windows Server 2003 x64 Edition SP2 and prior
• Windows Internet Explorer 7 for Windows Server 2003 with SP1 or SP2 for Itanium-based Systems
• Windows Internet Explorer 7 for Windows Vista
• Windows Internet Explorer 7 for Windows Vista x64 Edition