New Delhi: Linux For You, Asia's leading Linux magazine, has released an advisory against a major virus attack on this Saturday. The virus, named Blaster, activates on every Saturday. It caused a major havoc in the US, Europe and parts of Asia when it was first reported on last Saturday.

Says Linux For You editor Rahul Chopra: "The last Saturday was a holiday in most offices in India and the virus could not cause noticeable damage. This Saturday the damage could be substantial."

Blaster is like a time bomb, which activates every Saturday. In the US, it caused the US Federal Reserve Bank (equivalent to India's Reserve Bank of India) to shut down its computer systems. According to an estimate, it affected 4 per cent of the total computer systems in the world last Saturday. The virus is in form of a worm and affects Windows NT 4.0, NT 4.0 Terminal Services Edition, Microsoft Windows 2000, Microsoft Windows XP, and Microsoft Windows Server 2003.

The worm has been rated as one of the most dangerous threats to computer systems by anti-virus software companies such as Symantec, Sophos, Trend Micro, McAfee and others. It utilises a bug in various versions of Windows and causes PCs to crash. It self-replicates itself and spreads across to other systems within the network and via Internet. It allows other users to get access to your systems. It also issues warning messages to users saying that users have 60 seconds to save data and the machine reboots. It also sends denial of service attacks (DoS) to Microsoft websites.

The only cure for this worm is to update Windows by going to immediately. Another option is to switch to a secure operating system such as LiFY. The US Department of Homeland Security and Microsoft have warned users separately to immediately update their windows.