North Korea has for years carried out a government-backed hacking campaign, so this news is no surprise. While exploiting a tragedy to distribute a corrupted document would be outrageous for any country in the world, it hardly constitutes a new low for Pyongyang which, rather than offering up condolences over the incident, instead fired an unprecedented barrage of missiles during the South's period of mourning.
The US has a reputation for blaming cyber attacks on its enemies, even while hypocritically hacking, wiretapping, and carrying out criminal cyber acts — it should come as no surprise that the US-based company Google is now accusing North Korea of hacking activities. Washington does not want to protect cyberspace, but rather to create a confrontational environment that favors its hegemony.
There's a 14% chance that any single cyberattack in 2022 will result in damages over $10B, according to the Metaculus prediction community.