North Korean hackers attempted to breach the servers of the U.S.-based vaccine manufacturer Pfizer, and its German partner BioNTech, in hopes of gathering scientific data that could be used to manufacture bootleg copies of a COVID-19 vaccine to sell on international black markets, according to intelligence officials in Europe.

North Korea’s intent was likely to raise funds in foreign currency. The hermit dictatorship’s domestic currency is mostly worthless outside its borders.

Two European security officials briefed on cyber-operations told Insider the attempted intrusion was likely an official North Korean operation to gather scientific data on Pfizer’s COVID-19 vaccine, one of just three vaccines so far approved for emergency use by the World Health Organization. Both officials said the attempt was connected to November’s announcement of multiple hacking intrusions via Microsoft network infrastructure.

“It clearly was an information-gathering attempt rather than a malware– or ransom-style attack. I will not get into technical details but we have developed plenty of experience with each type of attack,” said a European official, who would not be named because of the extreme sensitivity of the situation.