The U.S. Homeland Security Department has said computer attackers last year launched six strikes against atomic firms and seven offensives on sites housing potentially hazardous chemical substances, CNN reported last week.
A DHS electronics crisis group said "several" attempts to infiltrate computer systems at nuclear companies had succeeded. "These organizations reported that their enterprise networks were compromised and in some cases, exfiltration of data occurred," it stated.
The group indicated it did not believe any attacker had managed to break into atomic command mechanisms.
Homeland Security identified 198 cyber strikes in 2012 against targets encompassing U.S. energy, water and atomic operations. The actual number could be higher. Issue experts said most attacks do not receive notice and a significant number of firms opt against informing the government of electronic strikes.