In 2022, hackers from North Korea stole more crypto assets than in any previous year, according to a confidential United Nations report.

The UN report also observed that cyber attacks were more sophisticated than in prior years, making the recovery of stolen assets more difficult than ever before.

Last week, according to Reuters, the report was submitted to a 15-member North Korea sanctions committee.

After targeting the networks of global aerospace and defense industries, it was determined that hackers with ties to North Korea were responsible for between $630 million and more than $1 billion in stolen crypto assets in 2017.

"[North Korea] used increasingly sophisticated cyber techniques both to gain access to digital networks involved in cyber finance, and to steal information of potential value, including to its weapons programmes," the independent sanctions monitors said in its report to the UN Security Council Committee.

North Korea has consistently denied charges that it is responsible for cyberattacks, but a recent UN assessment claims that North Korea's principal intelligence department, the Reconnaissance General Bureau, employs numerous cyberattack groups, including Kimsuky, Lazarus Group, and Andariel.

"These actors continued illicitly to target victims to generate revenue and solicit information of value to the DPRK, including its weapons programs," the UN report said.

Last week, a report published by blockchain analytics firm Chainalysis reached a similar conclusion, attributing North Korean hackers to at least $1.7 billion worth of stolen cryptocurrency in 2022, making it the worst year ever for crypto hacking.

The company identified the cybercriminal networks as the most "prolific cryptocurrency hackers over the last few years."

North Korea's overall exports in 2020 amounted to $142 million, so it's not an exaggeration to state that cryptocurrency hacking is a substantial portion of the nation's economy, according to Chainalysis.

According to Chainalysis, at least $1.1 billion of the stolen funds were obtained through hacks of decentralized finance protocols, making North Korea one of the primary reasons behind the 2022 uptick in DeFi hacking.

In addition, the company discovered that hackers with ties to North Korea frequently transfer huge sums to mixers like Tornado Cash and Sinbad.

"In fact, funds from hacks carried out by North Korea-linked hackers move to mixers at a much higher rate than funds stolen by other individuals or groups," Chainalysis said.

The full report, which was presented to the 15-member council sanctions committee on North Korea last week, is expected to be made public later this month or in early March, Reuters said.