Two Massachusetts accounting firms separately recently notified the Office of the Massachusetts Attorney General and the Office of Consumer Affairs and Business Regulation of data breach incidents at their firms, resulting in the unauthorized access of their respective clients’ names, addresses and Social Security numbers.

The first accounting firm, King McNamara Moriarty LLP (KMM) discovered a malicious file on its network which may have affected the personal information of almost 6,000 Massachusetts residents. The file was discovered by the firm after the conclusion of an independent forensic investigation due to an earlier suspected “malicious hacking incident.” The discovery prompted the accounting firm to engage another forensic firm who investigated and removed the malicious file. The second accounting firm, M. Stanley Metz & Co. Inc., reported potential unauthorized access to the firm’s client tax return program, which may have affected the personal information of 2,337 Massachusetts residents. Affected clients at both firms were offered free credit and identity monitoring.