ON FRIDAY, A COMPUTER VIRUS CALLED "WANNACRY" hit about 100 countries worldwide. The ransom ware encrypted data on the computers, demanding payments of up to $600 to restore access. Beijing News comments:

With computer security agencies taking responsive measures, the attack has weakened. Actually, the virus is not totally new - it used the EternalBlue exploit developed by the United States' National Security Agency that was stolen by hackers.

The incident teaches us at least two lessons. First, there is nothing absolutely safe in the internet age. Even if developed by law enforcers, a powerful computer attack tool is at risk of being acquired by lawbreakers.