India is one of the most vulnerable countries to cyber attacks

While the US is ranked 11th safest of 44 nations studied, several Scandinavian countries like Denmark, Norway and Finland were ranked the safest in the book authored by V.S. Subrahmanian, professor of computer science at the University of Maryland.

The researchers based their rankings, in part, on the number of machines attacked in a given country and the number of times each machine was attacked.

Machines using Symantec anti-virus software automatically generated these reports, but only when a machines user opted in to provide the data.

Trojans, followed by viruses and worms, posed the principal threats to machines in the US.

However, misleading software (fake anti-virus programmes and disk cleanup utilities) was far more prevalent in the US compared with other nations that have a similar gross domestic product, the authors noted.

The results suggest that US efforts to reduce cyber threats should focus on education to recognise and avoid misleading software.