In June 2013 an attack on Belgacom surfaced. Even though it seems that it started 2011, Belgacom seemed to figure out that they are under attack as Exchange did not work properly anymore.
There are a lot of interesting details on the attack in this article: Operation Socialist.
What strikes me more than the attack itself is the behavior of the governments on the Internet. It seems that nobody cares about agreements and other sorts of contracts anymore. Everybody takes what they want and completely asymmetrically.
If we look at the United States, they were fairly clear how they treat attacks on their Cyber infrastructure: Cyber Combat: Act of War. It is hard to grasp still today (the article is from 2011) whether “only” sabotage counts as the lines are blurry. When does espionage end and where does the preparation for sabotage start? So with all the attacks going on, where it is suspected that there are state actors in the driver’s seat â€“ let’s hope nobody is treating this as an act of war. I guess it is time to agree on a convention which is then followed by all the countries.