Chaos Ransomware Strikes Optima Tax Relief, Leaks 69GB of Sensitive Customer Data

In a significant cybersecurity incident impacting the financial services sector, U.S.-based tax resolution firm Optima Tax Relief has reportedly suffered a ransomware attack orchestrated by the Chaos ransomware group. The attackers have allegedly exfiltrated and leaked approximately 69GB of data, including confidential corporate records and sensitive personal tax files.

The exposed information reportedly includes Social Security numbers, home addresses, phone contacts, and banking details — all highly valuable to identity fraudsters. Given the nature of tax records, cybersecurity experts caution that the risks for affected individuals could extend for years, as this type of data cannot simply be changed like passwords.

The ransomware group behind the attack, known as Chaos, has been active since March 2025 and is rapidly gaining notoriety for targeting organisations with vast stores of personally identifiable information (PII). Unlike the earlier Chaos ransomware builder seen in 2021, this iteration appears to be a more organised threat actor, employing a strategic approach in selecting its victims.

This isn’t their first major claim. In May, Chaos asserted responsibility for a breach involving The Salvation Army, though that incident has yet to be independently verified. 

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Chaos Ransomware Strikes Optima Tax Relief, Leaks 69GB of Sensitive Customer Data