As North Korea continues to escalate tensions on the Korean peninsula with the threat of nuclear war, hacktivist collective Anonymous hacked into  North Korea's official Twitter and Flickr account and revealed the user registration list of the country's official website.
The group posted a warning on April 2, 2013, claiming to have stolen user records  from the North Korean government website, and published the content two days later.
A majority of South Korean net users initially welcomed the news. But opinion quickly soured after it was reported  [ko] that 2,000 among the 9,001 users in the registration list are believed to be South Koreans, including [ko] activists, labor groups, members of the media, and academics, fueling concerns over possible human right violations  following this revelation.
Joining North Korean sites is considered a serious anti-state activity in South Korea and is punishable by law  up to several years in prison.
As proof of the claim that the collective had hacked North Korea, the North Korean Twitter feed  sent out tweets  that read “hacked” with links to North Korea-related websites. One tweet said “Tango Down” and linked to North Korean Flickr account  where an unflattering image of Kim Jong-un with pig ears and nose and a Mickey Mouse belly tattoo was displayed. Texts in the image criticized Kim for “threatening world peace with ICBMs and nuclear weapons”, “wasting money while his people starve” and “concentration camps and the worst human rights violation in the world”.
The image has since been removed, but there are screen captures  of the image when it was live.
Anonymous later posted its video press release  YouTube.
The collective also published the confidential user records  of North Korean news and information website Uriminzokkiri.com  in PasteBin site, exposing users ID, sex, name, email, date of birth and password which appears to be hashed .
Many raised concerns on social media that the list of usernames published by Anonymous could be used to “rat out” supposedly pro-North South Koreans:
@0103geeehyun : 회원명단 *상세하다… 해킹의 취지가 자꾸 도발하는 북한 위협하려는것이었을텐데 여론은 부차적으로 종북세력 척출해내는데에 초점..공개됨으로써 우,좌 대립은 더 세지겠군. 애니웨이 난 전쟁없는 나라에서 살고시퍼요
@0103geeehyun : The registration list is so f**cking detailed. The initial purpose of the hacking would be to blackmail North Korea who keep making provocations, but people seem to focus (not on the hacking itself but rather on) ratting out “pro-North” people in South Korea. By revealing this list, the conflict/division between the right and left side will grow deeper than ever. Anyways, on a personal level, I just want to live in a country with no war.
@jwmuzik_ : 국제해커집단 어나니머스가 북한사이트 ‘우리민족끼리'를 해킹하여 9000여명의 가입자명단을 공개했는데, 그중에 상당수가 한국인이라는 소식. 대부분은 간첩과는 전혀 상관없는 평범한 사람들이고 일베충도 많던데 이메일도용당한 것으로 추정됨.
@jwmuzik_ : International hacker group Anonymous hacked North Korean site “Uriminzokkiri” and disclosed a list of 9,000 names who registered for the site and quite a lot of them were proven to be South Koreans. Most of them are believed to be innocent and irrelevant people and even few are users on the Ilbe site  (extreme right-wing website taking a hostile stance against the North). It seems there have been email/identity theft.
Some conservatives as well as right-wing groups lavishly thanked [ko] Anonymous for disclosing names of people they believe either to be North Korean spies or pro-North South Koreans.
But many pointed out the naivete and ignorance of assuming that the collective had done something just to benefit the South Korean government, or any government for that matter.
@s_hunpark : 북한사이트 해킹한 어나니머스, 근데 우리나라 언론은 이들이 아나키즘적 성격의 해커그룹이란 것을 많이 강조하고 있지는 않은 것 같다. 심볼과 그간의 활동만 봐도 아나키즘적 성향이 매우 강한 해커그룹인데[…]
@s_hunpark : Anonymous hacked North Korean sites– what Korean local media choose to ignore is the group's anarchistic nature. Their previous activities and their symbols shows that they are an anarchist group (that doesn't believe in government of any kind).
More serious discussions have formed around the possibility of this data being used to investigate and monitor citizens. Influential Twitterati and lawyer Choi Young-ho (@Lawyer_Korea ) answered  [ko] the legal question:
@Lawyer_KOREA : […] 거기서 취득한 자료 자체를 국가보안법상 이적단체가입,방조의 증거로 사용할 순 없어도, 거기 나온 생년월일, 이멜주소로 특정된 2차 자료사용은 적법(대법원 판례)
@Lawyer_KOREA : According to Supreme Court precedent, (people can) use information from the Uriminzokkiri site, although this information would not be accepted as a legal proof of someone joining, aiding, and abetting an anti-state organization under our national security law. However, they can surely use the date of birth and email address as secondary sources in court.