Microsoft Warns of Critical Security Flaws

Microsoft Corp. on Tuesday warned users of its Windows operating system of two "critical" security flaws in its software that could allow attackers to take complete control of a computer.

The world's largest software maker issued patches to fix the problems as part of its monthly security bulletin. The problem mainly affects the Windows operating system.

The warning came after the company last week made a patch available earlier than expected to fix a different critical flaw in the Windows operating system.

"People should always be vigilant about not opening unexpected attachments or following links to Web sites that arrive via e-mail or instant messages," said Oliver Friedrichs, a senior manager at Symantec Corp.

"Increasingly, criminals are delivering crimeware -- such as bots, Trojans, and spyware onto unsuspecting users' computers through spammed messages."

Computer security experts and Microsoft urged users to download and install the patch available at www.microsoft.com/security.

Microsoft defines a flaw as "critical" when the vulnerability could allow a damaging Internet worm to replicate without the user doing anything to the machine.

For more than three years, Microsoft has been working to improve the security and reliability of its software as more and more malicious software targets weaknesses in Windows and other Microsoft software.

More than 90 percent of the world's personal computers run on the Windows operating system.