According to the AFP, numerous S. Korean websites came under a Distributed Denial of Service (DDoS) attack today:
AhnLab said sites included those of the presidential Blue House, the US forces, the military Joint Chiefs of Staff, the ministries of foreign affairs, defence and unification, the spy agency, parliament and the tax office.
AhnLab said its own website had also come under attack along with those of seven major banks in the incident that began at 10 am (0100 GMT).
According to the article, some of the sites were back up within an hour of the attack. The attack was similar to an attack in 2009 that shut down 25 sites including one in the US. The South Korean intelligence blamed N. Korea for that attack.
More information will be released as it becomes available.