CSA Tax & Advisory (CSA), a licensed accounting firm based in Haverhill, Massachusetts, has allegedly been compromised by the Lynx ransomware group. The firm, which has over 75 years of experience, specializes in personal financial planning, estate planning, and tax services for business owners and executives. On December 26, 2025, the Lynx group added the firm to its data leak site, claiming to have exfiltrated sensitive internal and client records.
According to the actor, the allegedly compromised data includes:
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Full names
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Social Security numbers (SSNs)
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Physical addresses
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Phone numbers
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Individual income tax returns (Form 1040)
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IRS e-file signature authorizations (Form 8879)
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Tax payment vouchers (Form 1040-V)
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Employer certification forms
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Internal corporate correspondence and financial records
