Hackers linked to Russian intelligence are targeting high-profile users of popular messaging applications, according to a warning from the FBI and CISA. The primary targets include U.S. government officials, military personnel, political figures, and journalists. The attackers compromise accounts to access messages and contact lists, allowing for further phishing attempts. Signal users are particularly at risk, though techniques can extend to WhatsApp and Telegram. The hackers use social engineering tactics, impersonating official support accounts to trick users into revealing sensitive information. The FBI and CISA advise users to be cautious of unexpected messages and suspicious links. Victims are encouraged to report incidents to the Internet Crime Complaint Center (IC3).