The National Cyber Security Centre (NCSC) has issued guidelines for individuals vulnerable to targeted attacks via messaging applications, particularly due to increased malicious activities from actors based in Russia. High-risk individuals, such as those with access to sensitive information, are especially susceptible. Past incidents involve state-affiliated groups like APT31 from China, the Russian FSB actor Star Blizzard, and Iran's IRGC targeting government officials. Attackers may use deceptive methods to obtain login codes, add devices to accounts, infiltrate group chats, impersonate contacts, and execute phishing attempts. To mitigate risks, individuals should avoid sharing sensitive information via messaging apps, use corporate services for work-related communications, refrain from sharing verification codes, activate two-step verification, utilize passkeys, regularly review linked devices, stay alert for impersonations, and consider using disappearing messages. The NCSC also provides guidance for enhancing account and device security for high-risk individuals.