If you thought you could escape hearing about WannaCry one more time before the close of 2017, you were sadly mistaken. Today, US Homeland Security Advisor Tom Bossert publicly pinned responsibility for the ransomware outbreak on North Korea in an op-ed piece in The Wall Street Journal.

When the global cyberattack occurred in May, it spread rapidly, targeting hospitals, businesses, banks, and other critical institutions, inflicting economic distress and – for the hospitals and health systems hit – putting lives at risk. Quoting from Bossert’s op-ed, Nick Statt from The Verge writes, “We do not make this allegation lightly. It is based on evidence. We are not alone with our findings, either. Other governments and private companies agree. The United Kingdom attributes the attack to North Korea, and Microsoft traced the attack to cyber affiliates of the North Korean government.”

The US believes that The Lazarus Group, which works on behalf of the North Korean government, is responsible–the same group behind the 2014 Sony cyberattack.

The scale and speed of WannaCry was unprecedented, and alarmed many around the globe, as it unfolded. Yet its execution was deemed somewhat sloppy by industry experts. Tom McKay from Gizmodo writes, “The software locked users’ computer systems and demanded ransoms in Bitcoin, generating an embarrassingly small amount of actual cryptocurrency ransom but leaving a digital paper trail a mile wide. The attack was eventually slowed down due to an amateurish mistake in WannaCry’s code that exposed its kill switch, though updated versions of the malware are still circulating.”

As Reuters and others report, North Korea has repeatedly denied responsibility for the wave of cyberattacks.

A more formal announcement from the White House is expected Tuesday.

Read the full story at Reuters.