Jones Day law firm discloses breach affecting 10 client files

International law firm Jones Day confirmed Monday that hackers accessed files belonging to 10 clients in a cybersecurity breach, marking another incident affecting the legal sector's handling of sensitive corporate and government information. The firm, which ranks among the largest in the United States by revenue, said it detected unauthorized access to specific client matter files but did not disclose the identity of affected clients, the nature of compromised information, or attribution of the attack. Legal industry observers noted that law firms remain attractive targets for espionage and ransomware actors due to their repositories of confidential merger negotiations, intellectual property disputes, and regulatory defense strategies. Jones Day's disclosure follows a pattern of increasing attacks against major law firms, including previous incidents affecting other Am Law 100 firms. The firm said it has notified affected clients and relevant authorities, and has engaged cybersecurity consultants to investigate the breach scope and implement additional security measures. Regulatory filings may be required depending on the jurisdictions and sectors of affected clients.