Microsoft Tuesday issued two security updates detailing patches for applications in Windows and Office that the company deemed critical, because one of the vulnerabilities could sneak up on administrators via third-party software installations.
Microsoft goes small for next week's Patch Tuesday
Industry watchers expect to see more patch updates from vendors other than Microsoft in response to Security Bulletin MS10-031. Microsoft categorized this vulnerability as critical for all supported versions of Microsoft Visual Basic for Applications SDK and third-party applications that use Microsoft Visual Basic for Applications. This security update is also rated Important for all supported editions of Microsoft Office XP, Microsoft Office 2003, and the 2007 Microsoft Office System, the company stated in the bulletin.
"The vulnerability could allow remote code execution if a host application opens and passes a specially crafted file to the Visual Basic for Applications runtime. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system," according to Microsoft.
The issue for IT departments regarding this update is that third-party vendors could pass the vulnerability along in their applications. Also this vulnerability doesn't require significant action to be taken by end users to kick off malicious activity, according to Joshua Talbot, security intelligence manager, Symantec Security Response.
"I've put the Visual Basic for Applications vulnerability first on my list," Talbot said, in a statement. "The VBA vulnerability requires less action from a user. For instance, an attacker would simply have to convince a user to open a maliciously crafted file — likely an Office document — which supports VBA and the user's machine would be compromised. I can see this being used in targeted attacks, which are on the rise."
Defined as critical by Microsoft, MS10-030 addresses a privately reported vulnerability in Outlook Express, Windows Mail and Windows Live Mail. The vulnerability could enable remote code execution if an end user visits a malicious e-mail server, according to Microsoft. The security risk addressed with this patch could quickly "crop up" again for IT departments, says Jason Miller, data and security team manager for Shavlik Technologies in Minneapolis.
"With Windows Live Mail, a user could install Windows Messenger, which would ultimately land this on your system," Miller explains. "Usually operating system patches apply to the base default operating systems, but this one has a series of cases in which it is not installed out of the box."
The attack vector for this vulnerability is still less likely to be exploited, according to Wolfgang Kandek, CTO of Qualys.
"Successful exploitation however is unlikely (exploitability index = 2 ) as it requires extensive user involvement including setting up an e-mail account on a malicious server," Kandek wrote in a statement. "We don't see Outlook Express/Windows Mail being used in the enterprise but smaller businesses could be affected."
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