A server located in China was used for the attack on the Japanese Lower House. Hackers had access to emails and documents belonging to the chamber’s 480 legislators for at least one month. Information on military aircraft and nuclear power plants may have been stolen in a series of cyberattacks on Japanese defence contractor Mitsubishi Heavy. This shows that even for companies acting in sensitive markets where the level of security is normally at the top level, it is difficult for them to protect themselves. This gives perspective on the challenge currently faced by other private sector organisations.
Source: https://thehackernews.com/2011/10/japan-under-heavy-cyber-attack.html