Security Alert: Internet Explorer VBScript Vulnerability

A zero-day remote code execution vulnerability has been discovered in the way that VBScript interacts with Windows Help files when using Internet Explorer. A remote attacker can exploit this vulnerability by convincing a user to visit a specially crafted Web page. Successful exploitation could result in execution of arbitrary code on the affected system.

The vulnerability is reported to affect widely used Internet Explorer running on Windows 2000, Windows XP, and Windows Server 2003 while testing shows that Windows 7, Windows Server 2008 R2, Windows Vista, or Windows Server 2008 are not vulnerable. The vulnerability is due to the VBScript functionality available from within Internet Explorer that exposes the MsgBox function, allowing script on a web page to display a message to the user. The parameters supplied to the MsgBox function may reference an associated Window Help file. A remote attacker could exploit this issue by convincing a user to visit a malicious Web page that contains a dialog box which will trigger the execution of arbitrary code when the user presses the F1 key. The F1 key launches winhlp32.exe within an attacker supplied .hlp file. Successful exploitation of this issue may allow the attacker to take complete control of the affected system. A proof of concept of the exploit is available in the wild.

Microsoft publicly disclosed information on the exploit in a Security Advisory on March 1st and one day later Check Point provided immediate protection against exploits that use this vulnerability through its integrated and dedicated IPS offerings. Check Point SmartDefense, IPS Software Blade, and IPS-1 detect and block attempts to exploit this vulnerability. For more information, see CPAI-2010-049.


Source: Check Point Software Technologies