The LockBit ransomware gang has claimed responsibility for an attack on financial services company ION Trading UK Ltd. that has forced derivatives traders to resort to manually processing trades.

In a statement, ION described the attack as a “cybersecurity event” that commenced Tuesday, affecting some services in the ION Cleared Derivatives division. The incident is said to have been contained to a specific environment, affected servers disconnected and the remediation of services is underway.

According to Reuters today, the attack has left scores of brokers unable to process derivatives trades, with attempts to remediate the situation possibly taking days.

ION didn’t disclose the form of attack, but LockBit has claimed responsibility for the attack on its dark web leaks site (pictured). The listing doesn’t provide details on how LockBit gained access to ION’s network, but the ransomware gang is threatening to release all the data it stole from the company on Feb. 4 if demands aren’t met.

LockBit does not say what its demands are, but given its usual modus operandi, it will be demanding that ION pay a ransom payment for a decryption key and a promise not to release the stolen data. Bleeping Computer noted today that if LockBit did indeed steal data from ION, leaking it may expose sensitive information belonging to large investors, causing significant financial and organizational damage.

Notable ION customers that may be affected by the data theft include ABN Amro Bank N.V. and Italy’s largest bank Intesa Sanpaolo s.P.A.

Authorities on both sides of the Atlantic are said to be investigating, including the U.K. Financial Conduct Authority, the Prudential Regulation Authority and the U.S. Federal Bureau of Investigation.

“This is a reminder not only of third-party and supply chain risks but also that large, well-known organizations that invest heavily in cyber security” can also be targeted, Javvad Malik, security awareness advocate at security awareness training company KnowBe4 Inc., told SiliconANGLE. “It’s why conducting thorough risk assessments is important in order to identify what business processes are important so that the appropriate controls and resilience can be built into the system.”

After bizarrely apologizing for a ransomware attack on a children’s hospital at the beginning of January, LockBit was more recently in the news following an attack on Royal Mail Group Ltd. on Jan. 12. The LockBit attack disrupted computer systems used by Royal Mail to process overseas deliveries, causing severe disruption.

Image: LockBit