A cyber attack on three of South Korea’s major broadcasters and several of its major banks appears to have been caused by a relatively unsophisticated piece of software, security researchers said Wednesday. [Story updated, see below]

The attacks, which began at around 2pm local time on Wednesday (5:00 UTC) left desktop and laptop computers unable to start at KBS, MBC and YTN and took the auto-teller machines at Shinhan Bank and Nonghyup Bank offline. It didn’t affect the ability of the TV stations to put out programming.

The root of the attack was a malicious piece of software identified by computer security company Sophos More >