The interior ministry said it was carried out by organised hackers from several different foreign countries and Aramco employees and contractors were not involved. The attack used a computer virus known as Shamoon, spread through Aramco’s network and wiped computers’ hard drives clean. The company said damage was limited to office computers and did not affect systems software that might harm technical operations. Later, Hacker group called Cutting Sword of Justice claimed responsibility for the attack. A posting on the website of the group accused Saudi Arabia of crimes and atrocities in countries that include Bahrain and Syria.
Source: https://thehackernews.com/2012/12/aramco-cyber-attacks-intends-to-stop.html