CIH.1003 is a resident virus that activates every April 26. It was given this name because the date coincides with the commemoration of the nuclear disaster that took place in Chernobyl in 1986.
This virus is extremely dangerous, as it deletes the content of the hard disk, preventing Windows NT/98/95 computers from starting up. It also infects files with an EXE extension, but only in Windows 98/95 computers.
In computers with an Intel Pentium microprocessor, it deletes the content of the BIOS.
CIH.1003 does not spread using its own means, but it infects other files. It reaches computers when these infected files are distributed, which can enter computers through any of the typical means of tranmission, which include, among others, floppy disks, e-mail messages with attached files, Internet downloads, FTP, IRC channels, peer-to-peer file sharing programs (P2P), etc.