Four Bay Street Law Firms Hit by Coordinated Cyberattack

McCarthy Tetrault says it detected the intrusion late on Oct. 22 and brought in an outside cybersecurity firm to scope the activity. Its investigation found that an unauthorized third party accessed files that include client information. The firm has not said how many files were involved, but a source directly involved in the response told The Globe that 31,000 files were stolen.
Davies says a cyberattack on Oct. 23 led to "the compromise of information from one account." BLG says it found limited unauthorized access to part of its Microsoft cloud environment and confirmed that files, including client files, were viewed by an outside party. McCarthy Tetrault and Davies say they have notified law enforcement.

Several other Bay Street firms, including Osler, Goodmans, Fasken and Blakes, told The Globe they were not affected.