WASHINGTON - The US arm of China's largest bank ICBC said it was hit by a ransomware attack, forcing clients to reroute trades.
Ransomware attacks typically access vulnerable computer systems and encrypt or steal data, before sending a ransom note demanding payment in exchange for decrypting the data or not releasing it publicly.
The Industrial and Commercial Bank of China Financial Services (ICBC FS) said Thursday it "experienced a ransomware attack that resulted in disruption to certain (financial services) systems."
"Immediately upon discovering the incident, ICBC FS disconnected and isolated impacted systems to contain the incident," the New York-based bank said, adding that it was investigating the attack and working on recovery.
ICBC FS said it had successfully cleared US Treasury trades executed Wednesday and repurchasing (repo) financing trades Thursday.
Slack demand for $24 billion in 30-year US Treasury bonds that were auctioned Thursday came as a surprise to some analysts.
This sale "attracted very poor demand, one of the weakest I can remember," Karl Haeling of the bank LBBW told AFP.
Richard Flax, chief investment officer at Moneyfarm, said that some commentators believed the cyber attack "rather than weak demand, was behind the relatively poor US government bond auction."
However US Treasury Secretary Janet Yellen downplayed the attack's effects, stating Friday that "we've not seen an impact on the Treasury market."