Microsoft Corp. Tuesday released four new security bulletins detailing patches for several critical vulnerabilities, including one that fixes 14 separate flaws, in a wide range of Windows software.
The patches are part of the company's monthly rollout of security fixes and address a total of 20 flaws. The products affected by the flaws include Windows NT Workstation and Server, Windows 98, Windows XP, Windows 2000 and Windows Server 2003.
The patch detailed in Microsoft Security Bulletin MS04-011 is one of the biggest software updates the company has released in terms of the number of flaws it addresses.
A total of 14 vulnerabilities are addressed in the update, some of which are critical, said Stephen Toulouse, security program manager for Microsoft's Security Response Center.
In some cases, the patch addresses holes that are critical in some products but aren't as serious in others, Toulouse said.
Microsoft decided to address all these flaws in one patch because the fixes are all in the same file, Toulouse said.
"When we see the opportunity to ship one set of files that contain multiple fixes, we really attempt to do that" instead of shipping separate fixes, Toulouse said. The approach makes it easier for users to apply such patches, he said. "It was the best solution for our customers."
Among the critical flaws addressed in MS04-011 is a buffer overrun vulnerability that affects the Local Security Authority Subsystem Service (LSASS) interface for managing local security and domain authentication functions. Attackers who successfully exploit that flaw could gain complete control of a victim's system. Windows 2000 and Windows XP systems are the ones most at risk from this flaw, according to Microsoft.
Another vulnerability addressed in the same bulletin is a buffer overrun in the Private Communications Transport (PCT) protocol, which is part of the Microsoft Secure Sockets Layer library. The flaw could let attackers take administrative control of a compromised system and poses a critical danger to users of Windows NT 4.0 and Windows 2000.
MS04-011 also addresses critical vulnerabilities in the rendering of Windows Metafile and Enhanced Metafile image formats and Abstract Syntax Notation 1 language.
Meanwhile Security Bulletin MS04-012, details a cumulative upgrade that replaces several prior security patches.
The patch addresses four new flaws in a Windows component called the Distributed Component Object Model interface, which handles messages sent using the remote procedure call protocol. Successful exploitation of the most severe of these flaws could lead to a complete system compromise, meaning an attacker could take any action, including installing programs, deleting data or creating new accounts.
The third critical bulletin, MS04-013, contains details on a cumulative patch that fixes a remote code execution vulnerability in Outlook Express. The flaw lets attackers run HTML code of their choice in the Local Machine security zone in Internet Explorer to gain complete control of affected systems.
The fourth bulletin, MS04-14, which was rated Important by Microsoft, deals with a buffer-overrun flaw in the Microsoft Jet Database Engine that is used to provide data access to applications such as Microsoft Access, Visual Basic and third-party applications.
The number of flaws addressed by today's patches makes it imperative for users to apply them as soon as possible, said Michael Sutton, a director at iDefense Inc. in Reston, Va.
"This is one of the bigger (security announcements) I've seen them do," Sutton said. "It is definitely something that people should be paying attention to."
Some of the flaws addressed by today's patches are particularly dangerous, said Neel Mehta, a research engineer at Internet Security Systems Inc. in Atlanta.
The flaws in the PCT protocol and LSASS interface are likely to be "high-value targets" for hackers because they involve security and authentication components in Windows, Mehta said. "I expect it to be exploited in a very short time," especially because both flaws are very easy to take advantage of, Mehta added.