A scheduled denial of service attack against Microsoft Corp.’s main software update Web site did not materialize Saturday, as computers infected with the W32.Blaster worm failed to find their target.
Blaster first appeared on August 11 and quickly spread to computers worldwide by exploiting a known security vulnerability in Microsoft’s Windows operating system.
By Friday, the worm, which targets a Windows component for handling RPC (Remote Procedure Call) protocol traffic called the Distributed Component Object Model (DCOM) interface, spread to more than 423,000 systems, according to Oliver Friedrichs of Symantec Corp.
In addition to infecting vulnerable Windows machines, Blaster worm was programmed to launch a denial of service (DoS) attack against windowsupdate.com, an Internet domain owned by Microsoft and used to distribute software updates to Windows customers beginning on Saturday.
However, an error in Blaster’s design combined with last minute actions by Microsoft to change the registration of windowsupdate.com cut short that attack.
Blaster’s author provided the incorrect domain address for windowsupdate. The address specified in the worm’s code, windowsupdate.com, simply forwards users to the actual Windows update site, windowsupdate.microsoft.com, according to Mikko Hypp
