Experts at Sophos have advised companies to keep up-to-date with the latest Microsoft security patches and consider the benefits of Network Access Control (NAC) in light of the announcement of critical security flaws affecting the Windows operating system.

As part of its monthly "Patch Tuesday" schedule Microsoft has issued 11 new bulletins (six of them described as "critical") about security vulnerabilities in its software. The vulnerabilities cover a variety of different Microsoft technologies, including Windows, Internet Explorer, VBScript, and Office.

Sophos recommends that organizations roll-out the patches as a matter of urgency, as some of them could enable hackers to access data on a vulnerable PC or run malicious code such as a worm.

• Read more about the security patches now, and protect your computers

Network Access Control enables companies to control who and what is allowed onto their network; blocking unauthorized users, controlling guest access, and ensuring compliance with a business's security policy. By implementing NAC firms reduce the risk of unauthorized, guest, non-compliant, or infected systems compromising the network, ensuring that only correctly secured computers gain network access.

"NAC identifies managed, unmanaged and guest computers that do not comply with your security policy, and acts a vital tool when dealing with newly reported security vulnerabilities such as these," said Graham Cluley, senior technology consultant at Sophos. "You can quickly tell, for example, which computers are incorrectly patched or have the firewall disabled. You may then choose to automatically fix vulnerabilities before allowing the PCs to access your network, or simply block non-compliant computers. Whether your company is running NAC or not, it's important to take these latest security bulletins from Microsoft seriously and ensure that your business is properly protected."

Home users of Microsoft Windows can visit update.microsoft.com to have their systems scanned for Microsoft security vulnerabilities.

Sophos suggests that every IT manager responsible for security should consider subscribing to vulnerability mailing lists such as that operated by Microsoft at www.microsoft.com/technet/security/bulletin/notify.mspx.

• Network Access Control (NAC) - How compliant are your computers?
• Listen to a podcast about Network Access Control

Sophos continues to recommend companies protect their desktops and servers with automatically updated protection against viruses, spyware, hackers, and spam.

Tags: Kaspersky Internet Security 2009, Free Kaspersky Internet Security 2009 Download, internet security, antivirus software, antispyware software, personal firewall, antispam