Microsoft Knowledge Base Article 826955 contains the following summary:
On August 11, 2003, Microsoft began investigating a worm that was reported by Microsoft Product Support Services (PSS),
and the Microsoft PSS Security Team issued an alert to inform customers about the new worm. A worm is a type of computer virus that generally spreads
without user action and that distributes complete copies (possibly modified) of itself across networks (such as the Internet). Generally known as "Blaster,"
this new worm exploits the vulnerability that was addressed by Microsoft Security Bulletin MS03-026 (823980) to spread itself over networks by using open
Remote Procedure Call (RPC) ports on computers that are running any of the products that are listed at the beginning of this article.
This article contains information for network administrators and IT professionals about how to prevent and how to recover from an infection from the Blaster worm and its variants. The worm and its variants are also known as W32.Blaster.Worm, W32.Blaster.C.Worm, W32.Blaster.B.Worm, W32.Randex.E (Symantec), W32/Lovsan.worm (McAfee), WORM_MSBLAST.A (Trendmicro), and Win32.Posa.Worm (Computer Associates). For additional information about recovering from this worm, contact your antivirus software vendor. For additional information about antivirus software vendors, click the following article number to view the article in the Microsoft Knowledge Base:
49500 List of Antivirus Software Vendors
If you are a home user, visit the following Microsoft Web site for steps to help you protect your computer and to recover if your computer has been infected with the Blaster worm:
For additional information about a worm that is similar to the Blaster worm and that exploits the vulnerabilities that were addressed by Microsoft Security Bulletins MS03-026 (823980) and MS03-007 (815021), click the following article number to view the article in the Microsoft Knowledge Base:
826234 Virus Alert About the Nachi Worm