Microsoft has released five Security Bulletins warning of several vulnerabilities that put computers running Windows at risk of attack.
The flaws affect desktop as well as server installations of multiple Windows versions. However, none are rated "critical", Microsoft's highest severity rating. The software maker deems the issues it has reported this week as "important", the second highest on its severity rating scale.
In Microsoft's rating system for security issues, issues that require a user action to spread a worm, and could expose user data or threaten system resources, are rated important. (Only vulnerabilities that could allow a malicious internet worm to spread without any action on the part of the user are rated critical – highest risk.)
A set of vulnerabilities in the Windows word processing application WordPad affects many Windows releases, including Windows XP Service Pack 2 and Windows Server 2003. An attacker could exploit the flaws to gain complete control over the systems, Microsoft warned in bulletin MS04-041.
The WordPad flaws lie in conversion components of the application, Microsoft said. To exploit the vulnerabilities, an attacker would have to lure a victim to a specially crafted web page or send an attachment in email.
Microsoft deems the WordPad issue "important" on systems running Windows NT 4.0, Windows 2000 and Windows XP with Service Pack 1. Systems running Windows XP SP2 or Windows Server 2003 are at lesser risk, according to Microsoft. Also, an installation of Microsoft Word mitigates the risk, the vendor said.
Affecting the same Windows releases is a security vulnerability in HyperTerminal. A buffer overrun flaw in the Windows communications application could allow an attacker to take over a victim's system, Microsoft said in security bulletin MS04-043. A successful attack would require the victim to open a malicious HyperTerminal file, Microsoft said.
The HyperTerminal issue is "important" for systems running Windows NT 4.0, Windows 2000, and Windows XP. HyperTerminal is not installed by default on Windows Server 2003. Microsoft rates the issue "moderate" for that operating system.
Limited to Windows NT Server 4.0 are two flaws in the operating system's Dynamic Host Configuration Protocol server service. One could allow an attacker to launch a denial of service attack, disabling the DHCP service. The second vulnerability could allow remote code execution, Microsoft said in Security Bulletin MS04-042.
A set of flaws in the Wins (Windows internet name service) affect Windows NT Server 4.0, Windows 2000 Server, and Windows Server 2003. An attacker could gain control of a system running the software by constructing a malicious network packet, Microsoft said in Security Bulletin MS04-045.
WINS is a network infrastructure component. It provides a distributed database for registering and querying dynamic computer name-to-IP address mapping in a routed network. Details of a WINS flaw were first published last month on the BugTraq mailing list by security company Immunity.
Finally, Microsoft warned of security flaws in the Windows kernel and the Windows Local Security Authority Subsystem Service. Both are privilege escalation vulnerabilities, which could allow an attacker who has already logged on to a system to escalate his privileges and get full access, Microsoft said.
The kernel and LSASS issues affect Windows NT Server 4.0, Windows 2000, Windows XP, and Windows Server 2003, Microsoft said in bulletin MS04-044.
The bulletins released on Tuesday are part of Microsoft's monthly update cycle. The next "patch Tuesday" is the second Tuesday of January.