Bay Street Breach: 4 Law Firms, 31,000 Files [2026]

The Globe and Mail reports that McCarthy Tétrault and Davies Ward Phillips & Vineberg are also dealing with data breaches that have compromised thousands of files in total, including client information.[2]McCarthy Tétrault confirmed the breach to The Globe and Mail, but declined to comment on the number of affected files.[3]According to the Globe, across the four firms that were breached, at least seven employees granted the hackers access to internal files[4]. The paper reports that employees who followed the hackers' instructions were directed to fraudulent sign-in pages capable of bypassing MFA.[4]BLG chief executive David Di Paolo told the Globe that an unauthorized third party accessed "a portion" of the firm's Microsoft cloud environment, including files related to clients.[1]Bennett Jones said "the compromised information included reports on revenue from clients"[4], and the Globe reports that the firm said its document management system, where legal files are contained, and its accounting system[1] were not breached.The Globe reports that the Canadian Centre for Cyber Security on Wednesday cautioned that multiple Canadian firms have been targeted by cybercriminals impersonating internal IT support[1].Tech-insider.org reports that BLG hired Mandiant and McCarthy Tétrault hired CrowdStrike.[5] The outlet adds that the Globe says the hackers' identities are not known, and it reports no ransom or extortion demand.[5]Stikeman Elliott chair Peter Castiel told the Globe that "all the major law firms, and in particular all the CIOs [chief information officers], are sharing intel and best practices"[4].