As part of its Patch Tuesday update cycle, Microsoft just released four patches, all labeled as important, for a set of vulnerabilities reported last month.

The fundamental flaw found in the Domain Name System (DNS), offers hackers the possibility of redirecting unsuspecting Web surfers to alternate addresses and mess with the DNS records of network providers. Even though the dangers of DNS poisoning have been announced for quite some time, it is only recently that several demonstrations of such an action convinced the company to begin the work on a solution.

DNS is basically used for converting Web addresses into numerical sequences, which are then used by computers in order to move through the Internet traffic.

Unfortunately, even though the patches were developed to fix the problems, they managed to create others, as users of the popular ZoneAlarm firewall found themselves unable to access the Internet after applying the patch. Users reported their problems but so far there are no clear ways of dealing with the problem.

ZoneAlarm recommends for all users encountering this problem to uninstall the patch and wait for its bug to be handled.

The other three patches take care of some vulnerabilities found in Exchange server and SQL Server and also some bugs in Windows Explorer. The issues found in Windows Explorer can provide hackers with the means to install malware on vulnerable system using Windows Vista.

Apart from Microsoft Corp.’s efforts, Cisco Systems Inc. and Sun Microsystem Inc. also released on Tuesday several software patches for their users, significantly boosting the Internet access protection level.

"This is the largest synchronized security upgrade in the history of the Internet," said a statement from the Computer Security Response Team, or CERT, a division of Homeland Security. "An attacker could easily take over portions of the Internet and redirect users to arbitrary and malicious locations."

The flaw has been discovered by accident several months ago and a specially designed team composed of researchers from all the companies involved worked assiduously in order to develop the security patches released simultaneously on Tuesday.

It is believed that the flaw has not been exploited before the fix by hackers and the companies strongly advise all users to quickly install the patches to be sure that their systems are safe. Normally, computers should get the patch through their set automated updates, but in the cases where the users’ confirmation is required for all such activities, researchers encourage people not to neglect the matter and accept the system’s update.

Many of the technical details will still be unavailable for another month or so, in order for companies to have sufficient time to update the systems without the worry of hackers attempting to unpick the patch.

"This hasn't been done before and it is a massive undertaking," said security expert Dan Kaminsky, as quoted by BBC News. He also added that people should indeed be concerned about the issue but not panic about it, as it has been identified and handled in good time.