The software giant issued a dozen security patches, including a fix for the critical zero-day flaw that affects Word and another serious problem discovered in Explorer.
Microsoft released 12 individual security patches on June 13, addressing a handful of critical problems in Windows along with several less serious issues.
As previously reported, the software maker distributed a fix for the so-called zero-day flaw present in Microsoft Word and a critical glitch in Internet Explorer that relates to the manner in which the Web browser handles ActiveX controls.
The Word vulnerability has already been exploited in targeted attacks that appear to have been launched in China and Taiwan.
In all, the software maker issued patches for eight critical flaws, three important problems and one moderate glitch. The "critical" designation remains the highest maximum severity rating for Windows bulletins issued by Microsoft.
The cumulative security update for issues in Internet Explorer aims to resolve several newly discovered vulnerabilities, including some that have yet to be reported.
Microsoft said that an attacker who successfully exploits the most severe of the vulnerabilities could take complete control of an affected system, including gaining the ability to install programs, alter data or create new user accounts with full rights.
Among the problems specifically addressed by the Explorer patch are an exception handling memory corruption issue, an HTML decoding memory problem, the ActiveX control memory glitch, a COM object instantiation memory issue, a CSS cross domain information disclosure problem, an MHT memory corruption flaw and two separate address bar spoofing vulnerabilities.
The second critical patch addresses a remote code execution vulnerability in the way that Windows handles ART images. Using the flaw, Microsoft said an attacker could take control on an affected system by constructing a specially crafted ART image that could execute an attack if a user visits a Web site or e-mail message designed to flaunt the vulnerability.
The third critical update targets a vulnerability in Windows JScript that could allow remote code execution when using Internet Explorer, while the fourth is aimed at fixing a flaw in Windows Media Player that could allow remote code execution.
The fifth update involves a vulnerability in Windows routing and remote access tools that could also lead to remote code execution, and the sixth aims to address a problem in Windows graphics rendering engine that could allow remote code execution.
The final two critical patches involve the previously reported Word issue and a vulnerability in Microsoft PowerPoint that Microsoft said could allow for remote execution attacks.
Of the three issues earmarked by the software giant as "important," Microsoft addressed a vulnerability in its Exchange Server software that it said could allow script injection attacks when the server program is running outlook Web access.
Microsoft sounds malware alarm. Click here to read more.
The other two important patches aim to fix a vulnerability in Windows server message block software that could allow a remote attacker to elevate systems privileges, and a glitch in Windows TCP/IP settings that Microsoft said could also allow for remote code execution.
The final patch, involving a vulnerability rated only as "moderate," promises to address an issue in Windows RPC mutual authentication software that could allow spoofing attacks.
At Microsofts ongoing TechEd conference in Boston, company executives said that the software giant is making significant progress in securing its products by more closely examining code for potential vulnerabilities and adding onboard malware fighting tools.
The company is touting the security of its next-generation Vista operating system, due in 2007, as one of its greatest advances.
"People are finding that some of the problems theyve had with Windows XP are getting fixed with Vista," said Ben Fathi, corporate vice president of Microsofts Security Technology Unit.
"Weve gone through the entire life-cycle of product development and believe that doing so has greatly reduced the number of vulnerabilities well see reported in the future."
Check out eWEEK.coms for Microsoft and Windows news, views and analysis.