Microsoft has released five security patches, none critical but still rated "important" by the software giant. The flaws affect desktop and server installations of Windows.
According to its rating system, "important" is used for issues that require a user action to spread a worm, but could still expose user data or threaten system resources.
A set of vulnerabilities in WordPad affect even Windows XP SP2. An attacker could exploit the flaws to gain complete control over the systems, Microsoft warned in bulletin MS04-041. The flaws lie in conversion components. To exploit them, an attacker would have to lure a victim to a specially crafted Web page or send an e-mail attachment.
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 MS04-043. A successful attack would require the victim to open a malicious HyperTerminal file.
Limited to Windows NT Server 4.0 are two flaws in the operating system's DHCP (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 MS04-042.
A set of flaws in the Windows Internet Name Service (WINS) 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 MS04-045.
WINS is a network infrastructure component that 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 (LSASS). 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 MS04-044.
The bulletins are part of Microsoft's monthly update cycle. The next "patch Tuesday" is the second Tuesday of January.