A pedestrian walks pass a branch of Industrial & Commercial Bank of China (ICBC) in Fuzhou, Fujian province of China.
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The U.S. financial services division of Chinese bank ICBC was hit with a cyberattack that reportedly disrupted the trading of Treasurys.
ICBC, the world’s largest lender by assets, said on Thursday its financial services arm experienced a ransomware attack “that resulted in disruption to certain” systems.
Immediately after discovering the hack, ICBC “isolated impacted systems to contain the incident,” the bank said.
Ransomware is a type of cyberattack. It involves hackers taking control of systems or information and only letting them go once the victim has paid a ransom. It’s a type of attack that has seen an explosion in popularity among bad actors in recent years.
ICBC did not reveal who was behind the attack but said it has been “conducting a thorough investigation and is progressing its recovery efforts with the support of its professional team of information security experts.”
The Chinese bank also said it is working with law enforcement.
ICBC said it “successfully cleared” U.S. Treasury trades executed Wednesday and Repo financing trades done on Thursday. A repo is a repurchase agreement, a type of short-term borrowing for dealers in government bonds.
However, multiple news outlets reported there was disruption to U.S. Treasury trades. The Financial Times, citing traders and banks, reported Friday that the ransomware attack prevented the ICBC division from settling Treasury trades on behalf of other market participants.
The U.S. Treasury Department told CNBC: “We are aware of the cybersecurity issue and are in regular contact with key financial sector participants, in addition to federal regulators. We continue to monitor the situation.”
ICBC said the email and business systems of its U.S. financial services arm operate independently of ICBC’s China operations. The systems of its head office, the ICBC New York branch and other domestic and overseas affiliated institutions were not affected by the cyberattack, ICBC said.
—CNBC’s Steve Kopack contributed to this article.