This week's cyber attack on South Korean sites proves a nasty one—it involves data destruction. See the details of Symantec's and Sophos' investigations below. North Korea has certainly done nothing to deflect initial suspicion, but in fact it's not even the prime suspect. Some of the attacks are traced to Chinese addresses, and there's much speculation about a rogue group as the culprit.

Taiwan bulks up its cyber muscle in response to a threat from its cross-strait Chinese neighbor, and Sino-American talks open with a pointed US demand that China disavow recent cyber attacks.

Kaspersky finds some very old espionage malware active in Europe. Nigeria's Foreign Ministry comes under cyber attack, and the BBC's weather Twitter service is hijacked by the Syrian Electronic Army. The Spamhaus denial-of-service attack offers some rare insight into how such an exploit can be stopped: Spamhaus authorizes CloudFlare to speak.

NSS Labs' testing reveals good news about firewalls—they're getting better. A Foreign Policy think piece mulls the transition from "wars of iron" to "wars of shadow and silicon" (but RAND tells the US Congress it should tone down talk about "cyber war").

Bruce McConnell is new interim Deputy Undersecretary for Cybersecurity at the US Department of Homeland Security.

Reports that BlackBerry flunked a UK Communications-Electronics Security Group test were premature. Not only hasn't it flunked, but BlackBerry hasn't even been tested.

A new metric proposes to rank denial-of-service attacks on a severity scale similar to that used for hurricanes. MOOCs get mixed reviews.