By May 8 Microsoft hopes to fix a critical flaw in Windows Domain Name System servers reported last week that is being exploited by online criminals. Microsoft characterizes the level of attacks as "not widespread". Security experts confirmed that variants of the Rinbot worm (also called Nirbot by some vendors) had been scanning networks for vulnerable systems and then attempting to exploit the DNS bug. The problem only affects Windows 2000 and Windows Server 2003 systems, which can be tricked into running unauthorized software when an attacker sends them maliciously encoded Remote Procedure Call packets to the DNS server.
Microsoft has published a workaround for the problem, and the software vendor is weighing whether to step up its response and fix it ahead of May 8, the date of the company"s next scheduled security update. "While we don"t have a firm estimate on when we"ll complete our development and testing of updates for this issue, we have teams around the world working on it twenty-four hours a day, and hope to have updates no later than May 8, 2007. However, this is a developing situation and we are constantly evaluating the situation and the status of our development and testing of updates," said Microsoft security program manager Christopher Budd.