Microsoft has issued six security updates, fixing critical bugs in Windows components ranging from Internet Explorer to the Microsoft NetWare client service.
The updates were released Tuesday morning local time as part of Microsoft's monthly cycle of security patches. Five of this month's updates are rated critical by Microsoft, meaning that these bugs could be exploited by attackers to run unauthorized software on a system without user action. Microsoft rates the sixth update, which fixes the NetWare flaw, as "important."
The updates also fix Microsoft's XML (Extensible Markup Language) parser, the Windows Workstation service, the Microsoft Agent and the Macromedia Flash Player that is distributed with the operating system.
According to Symantec, the most critical of the updates is the Workstation service patch. "This issue can be exploited by remote anonymous attackers on Windows 2000, Windows XP and possibly Windows Server 2003 systems," Symantec said in a statement. "A wide variety of component technologies and services are impacted by this issue which has potential for a worm-style attack."
The Internet Explorer update is important, because unlike many of the other services being patched this month, Internet Explorer (IE) can easily be targeted by attack code placed on a Web site, said Roger Thompson, co-founder and chief technology officer with Exploit Prevention Labs Inc. "I think IE is always the most critical," he said via instant message.
Because hackers have also posted attack code that exploits a hole in the XML parser, the XML update is also noteworthy, he said.
Symantec also flagged the XML update. "All supported versions of Internet Explorer (including the new Internet Explorer 7.0) make use of this functionality and are susceptible to possible attack," the company said. "This is a publicly known vulnerability that is currently being exploited in the wild. "
November's update is the last for users of Microsoft's Software Update Services (SUS), which will no longer be supported as of Dec. 6. Microsoft is advising SUS users to upgrade to Windows Server Update Services 2.0 before the next security update, scheduled for Dec. 12.