Microsoft released a record number of software updates yesterday to fix at least 64 security vulnerabilities in its Windows operating systems and Office products, including at least one that attackers are actively exploiting.
Updates are available for all versions of Windows via Windows Update or Automatic Update. Nine of the patches earned Microsoft’s “critical” rating, which means the vulnerabilities they fix could be exploited to compromise PCs with little or no action on the part of the user, apart from visiting a booby-trapped Web site or opening a tainted file.
Redmond said three of patches should be top priorities. Two of them fix critical vulnerabilities in the “server message block” or SMB service, which handles Windows networking. Attackers could exploit the flaw addressed by MS11-020 by sending a single, specially crafted evil data packet to a targeted system. This is the type of flaw that should concern any network administrator, because it has high potential to be used to power an automated computer worm.
Microsoft also called attention to MS11-018, which is a cumulative security update for Internet Explorer that fixes critical flaws in all versions of the browser except the latest IE9, which is not affected. One of the IE vulnerabilities — the MHTML flaw I wrote about in January — is currently being exploited; another was discovered at the Pwn2Own hacking competition earlier this year.