IE Zero-Day Doesn't Make the Cut for Patch Tuesday
Microsoft published its advanced notification for next week's Patch Tuesday. The good news for the November updates is that there are will only be three security bulletins--a relatively calm month following a record-breaking October. The bad news is that the recently discovered IE zero-day is not one of the vulnerabilities being fixed.
According to Microsoft, there will be three security bulletins next week, addressing a total of eleven vulnerabilities. The products affected are Microsoft Office and Microsoft's Forefront Unified Access Gateway. One of the Microsoft Office vulnerabilities is particularly concerning--rated "Critical" and affecting all version of Office including Office 2010.
Wolfgang Kandek, CTO of Qualys, provides some expert insight regarding the upcoming Microsoft patches on his blog. "A "Critical" rating on an Office program is fairly rare, most vulnerabilities on the Office suite are categorized as "Important" because they typically require user interaction to get a successful exploitation. "Critical" here indicates a vulnerability that can be used to take control of the target machine without user interaction, such as MS10-064, where visualizing an e-mail in Outlook's preview pane was sufficient to trigger the flaw."
If Kandek is correct, IT admins will definitely want to review the associated security bulletin and apply the appropriate patches as soon as possible. Any exploit that can be triggered by simply viewing it is a serious security concern. At least when user interaction is required there is a chance--however small--that all of those months of security awareness training will pay off and users will have the common sense not to open file attachments or click on strange links.
The IE zero-day vulnerability will have to wait until next month apparently--unless it starts to be exploited in the wild enough to warrant an out-of-band update later this month. A Symantec Security Response blog post describes how the flaw was recently used in limited, targeted attacks, "Hackers had sent emails to a select group of individuals within targeted organizations. Within the email, the perpetrators added a link to a specific page hosted on an otherwise legitimate website."
Fortunately, the zero-day flaw is only really an issue for Internet Explorer 6, and maybe IE7. Internet Explorer 8 is protected because DEP (data execution prevention) is enabled by default, and protecting IE7 is as simple as enabling the optional DEP protection. Another alternative is to switch to using the beta of IE9--which is not vulnerable to the exploit at all.