The FBI is investigating a significant cyber espionage campaign attributed to Chinese hackers who infiltrated the networks of major U.S. law firms and technology companies, including the prominent Washington-based law firm Williams & Connolly. This breach, uncovered in early October 2025, involved the hackers accessing a small number of attorney email accounts through a zero-day attack exploiting previously unknown software vulnerabilities. Williams & Connolly, known for representing high-profile American political figures such as Bill and Hillary Clinton, reassured clients that there is no evidence that sensitive client data or core files were extracted. The firm, with assistance from cybersecurity experts at CrowdStrike and Norton Rose Fulbright, identified the hackers as likely state-sponsored actors engaged in a broader campaign targeting U.S. legal services to collect intelligence related to national security and international trade. The FBI’s Washington field office is leading the probe into this incident and more than a dozen similar breaches affecting other law firms and tech companies, emphasizing ongoing concerns over persistent Chinese cyber threats in critical U.S. sectors. China has denied involvement in these cyber attacks.