Immediate action is required, they say, to combat this threat, which is about to unleash itself – on Wedneday 31st July. Users that have deployed vulnerable software (Microsoft IIS Versions 4.0 and 5.0) must install a security patch. On July 19, the Code Red worm infected more than 250,000 systems in just nine hours. The worm scans the Internet, identifies vulnerable systems, and infects these systems by installing itself. Each newly installed worm joins all the others causing the rate of scanning to grow rapidly. This uncontrolled growth in scanning directly decreases the speed of the Internet and can cause sporadic but widespread outages among all types of systems. Code Red is likely to start spreading again on July 31, 2001, and has mutated so that it may be even more dangerous. Says Microsoft, “This spread has the potential to disrupt business and personal use of the Internet for applications such as electronic commerce, email and entertainment.” All groups are urging that every organisation or person that has Windows NT or Windows 2000 systems and the IIS web server software may be vulnerable. IIS is installed automatically for many applications. If you are not certain, says Microsoft, follow the ‘Step by Step’ instructions to determine whether you are running IIS 4.0 or 5.0. If you are using Windows 95, or Windows 98, no action is needed. If You Are Vulnerable, you need to: 1. To rid your machine of the current worm, reboot your computer. 2. To protect your system from re-infection: Install Microsoft’s patch for the Code Red vulnerability problem: Windows NT version 4.0 www.microsoft.com/Downloads/Release.asp?ReleaseID=30833 Windows 2000 Professional, Server and Advanced Server www.microsoft.com/Downloads/Release.asp?ReleaseID=30800 Step-by-step instructions for these actions are posted at www.digitalisland.com/codered Microsoft’s description of the patch and its installation, and the vulnerability it addresses, is posted at: www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulleti n/MS01-033.asp