Canadian Law Firm McCarthy Tétrault Confirms Major Data Breach
McCarthy Tétrault, a leading Canadian corporate law firm, confirmed a data breach discovered on October 22 that compromised thousands of files containing client information. The firm has notified clients, law enforcement, and regulators while working with cybersecurity experts to assess the incident.
McCarthy Tétrault, one of Canada’s top corporate law firms, has confirmed it suffered a major data breach that compromised thousands of files containing client information. 
The unauthorized access occurred over the week preceding public reports of the incident, with the firm detecting the breach late on October 22. According to one source directly involved in the matter, 31,000 files were stolen during the breach. McCarthy Tétrault confirmed the incident but declined to comment on the specific number of affected files.
Following the discovery, the firm engaged a cybersecurity company to determine the extent and scope of the unauthorized activity. The compromised data includes confidential client information, which raises concerns about the potential exposure of non-public merger and acquisition details as well as private communications between the firm and its clients.
McCarthy Tétrault is currently reaching out to its Bay Street clients to inform them of the breach and identify what information may have been compromised. The firm has also notified law enforcement and relevant professional regulatory bodies in Canada, offering its full cooperation in their inquiries.