Microsoft will this week issue nine security bulletins to fix 21 vulnerabilities, with four labelled "critical" and the rest "important".
The company on Thursday said the critical fixes would address flaws that could allow remote code execution in Windows, Internet Explorer, .NET Framework, and Silverlight, Microsoft's web development tool.
"Important" patches would address bugs in the Office suite, as well as server software, that could allow privilege escalation attackers to access more than intended through privilege escalation.
Wolfgang Kandek, CTO at vulnerability management firm Qualys, said the critical update to Internet Explorer should receive the highest priority, as criminals were ramping up their use of browser-based attacks.
"A couple of years ago, email was the most prevalent method of attack," Kandek said.
"Today, it is web browsers."
To illustrate his point, Kandek highlighted a vulnerability that was patched 10 January by Microsoft but was exploited roughly two weeks later.
The attack was delivered through the browser and involved a malicious audio file played via the Windows Media Player.
As usual, Microsoft advised users to apply these patches via Microsoft Update, Windows Update and the Microsoft Download Center to keep their software up to date.
Mac users can receive uploads automatically with Microsoft AutoUpdate for Mac.
This article originally appeared at scmagazineus.com
Copyright © SC Magazine, US edition
Issue: 338 | May 2015
Access CRN's extensive online resources including; email bulletins, community discussions and unique online news.
Processing registration... Please wait.
This process can take up to a minute to complete.
A confirmation email has been sent to your email address - SUPPLIED GOES EMAIL HERE. Please click on the link in the email to verify your email address. You need to verify your email before you can log on to the CRN website or start posting comments on articles.
If you do not receive your confirmation email within the next few minutes, it may be because the email has been captured by a junk mail filter. Please ensure you add the domain '@crn.com.au' to your white-listed senders.