Two critical patches for IE and Windows were added to the Patch Tuesday lineup in less than a week.
Two critical patches for IE and Windows were added to the Patch Tuesday lineup in less than a week.

Microsoft's Patch Tuesday release brings fixes for 31 bugs, including critical vulnerabilities in Internet Explorer, Windows and Forefront Protection for Exchange.

The monthly security update contains seven patches in total: four ranked “critical” and three deemed “important” by the tech giant.

All four of the critical fixes rectify remote code execution (RCE) bugs and, of note, two of the patches were added into the lineup after Microsoft's Patch Tuesday preview released last Thursday.

The recent additions were a patch, MS14-010, for Internet Explorer that addresses 24 RCE flaws in the web browser, and a fix, MS14-011, for a bug in the VBScript scripting engine in Windows.

According to Microsoft's February security bulletin, the most severe of the critical IE vulnerabilities could allow RCE if a user merely viewed a malicious web page via the browser.

“An attacker who successfully exploited the most severe of these vulnerabilities could gain the same user rights as the current user,” the bulletin warned. “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.”

As announced last Thursday, the security release also brought two critical patches for RCE bugs in Windows and Forefront Protection for Exchange.

The three “important” fixes in the Patch Tuesday roundup address flaws in .NET Framework, which could allow an attacker elevation of privilege; a bug in XML Core Services in Windows, which could lead to information disclosure upon exploitation; and a separate vulnerability in Windows, which could allow a saboteur to carry out a denial-of-service attack against victims.

On Tuesday, Wolfgang Kandek, CTO of vulnerability and compliance management firm Qualys, wrote in a blog post that the hefty IE patch addressing 24 RCE bugs was easily “this month's top Microsoft bulletin.”

“The bulletin is rated critical and affects all versions of IE, from IE 6 on Windows XP to IE 11 on Windows RT,” Kandek wrote.  “Attacks against the vulnerabilities addressed would come through the most common attack vector: malicious web pages.”