Student develops CIH virus antidote

One student invented it, but another has written an antidote to help users who lost data to the CIH computer virus.

The Chernobyl virus, also known as the CIH virus, was invented by one-time Taiwanese student Chen Ing-hau and caused havoc all over Asia on April 26, infecting thousands of PCs in South Korea, Singapore, India, Bangladesh and China. But it now has a cure, courtesy of Monirul Islam Sharif, an undergraduate computer science student at Dhaka University in Bangladesh.

Sharif, 21, says he wrote the 70KB C-language program, which he called MRECOVER, in 24 hours.

"I started working on it on April 27, when a friend brought his infected hard drive to me, and by the next day, it worked when I tried it out. Most of the data on the disk was recovered."

Sharif tried it on several other computers in Dhaka, and it worked there too, recovering data in minutes.

"If your machine uses FAT (File Allocation Table), MRECOVER will recover all the data on the disk within three to four minutes. But if your computer uses FAT 16, then it will recover all data after the first partition, limiting the recovery to between 40 and 60 per cent," Sharif said. He added that the antidote does not work on hard drives with a capacity of 8GB or more.

The program is free to use, and has been posted on the Web ( for anybody who wants to download it. A new and improved version for machines that use FAT 16 will be ready within days, and will be followed by one for large-capacity hard drives. Sharif says he has received 3000 hits and innumerable e-mail messages since he put MRECOVER on the Internet on May 5, but the inventor does not see any commercial gain from the program.

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