Edit 2/13: As Occam’s Razor (see Wired article) points increasingly towards Russia, keep the below discussion handy as a template for future complexities of North Korean tactics.

Reuters: Games organizers confirm cyber attack, won’t reveal source. A theory has attraction that, in other circumstances, would have all the hallmarks of conspiracy insanity.

South Koreans have a unique psychological susceptibility for their lost half, exceeding even that of West Germans during the Cold War. The vulnerability  has seen multiple uses by the North in the past, gaining aid and development from the South, which was diverted to the elite, or to funding the weapons programs of the North.

South Korea lives in denial. Two notable examples are:

• Sinking of the Cheonan, The conclusion that a North Korean torpedo had sunk the ship could not be formally reached, even though torpedo parts with North Korean markings were found  under the sunken vessel.
• The Kaesong Industrial Region, a special economic zone north of the DMZ, funded by South Korea, has been closed since 2/2016. A special panel chose to reject the presidential conclusion that wages paid to workers in the zone were diverted to  North Korea’s nuke program.

Quoting via Wikipedia,

The head of the panel Kim Jong-soo said, "The presidential office inserted the wage-diversion argument as major grounds, yet without concrete information, sufficient evidence and consultations with related agencies, mainly citing defector testimonies that lack objectivity and credibility...

Does Kim Jong-soo really expect North Korea to open up to Price-Waterhouse-Cooper? Defectors are the #1 source of information about this uniquely closed off country.

To South Koreans, North Korea is like the phantom limb of the amputee, never seen but perpetually a source of feeling. What North Korean strategist could ignore the precedent and practicality of exploiting this  sentimentality to undermine? Yet North Korea, isolated by another iron curtain, must not allow punctures by romantic approaches of the South. Analogously, reunification was never a dream of the GDR leadership. It came in the nightmare of collapse.

This suggests that North Korea seeks to manipulate the political landscape of the South, but without the annoying, cloying embrace of the great aunt you’ve never seen before. The public displays of the Olympics have the crowd swaying thrum of a national romance. All that is required is to convert the romance to an object of fear, but by actions perceptible only to South Korea’s leadership.

A hack by North Korea accomplishes this. It converts a feel-good love-fest, dangerous to the North, into a warning about political stability.

The major news sites tend to use hackneyed headlines. One of their favorites is, “So-and-so sends a message to so-and-so.” The body of such an article typically tries to decode the hidden-in-plain-view message.  Hack writing  fills up column inches, without being provably wrong in the short term.

But in this case, the headline “King-Jong-un Sends a Message to South Korea” has a significant chance of correctness.  It could make a nice article. The message:

Look at what we can do to you if you let the U.S. strike and/or support sanctions without relief. We can turn your government over at will. We can divide you against  yourself.

Division is the currently fashionable, deniable weapon of foreign affairs.