The out-of-band update, rated "critical," comes less than 20 days after the discovery of a sophisticated malware attack that combined the Windows zero-day flaw with security problems in SCADA systems and used stolen signed drivers to bypass security software.
Copycat attackers also added exploits for the Windows vulnerability into malware families, putting pressure on Redmond to release today's emergency fix.
From Microsoft's MS10-046 bulletin:
The vulnerability could allow remote code execution if the icon of a specially crafted shortcut is displayed. An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
The flaw affects all currently supported versions of Windows XP, Vista, Windows 7, Windows Server 2008 and Windows Server 2008 R2.
More to come...