Hung Cao told sailors and Marines on Aug. 19 to harden their social media profiles, hide ties to the military and report suspicious activity, warning that hostile actors are waging a coordinated, multi-domain campaign. The notice pushes Department of the Navy personnel to do something more immediate than check a box: treat their online lives as part of their security posture.
The warning lands now because it asks for immediate action from people who can be identified, tracked and targeted through what they post. Cao said recent incidents across the globe show a clear rise in adversary tactics, techniques and procedures, and he pointed to threats that include aerial drones watching bases, direct attempts to attack bases, harassment campaigns at bases and direct harassment of Navy and Marine Corps personnel and their families.
That is why the message goes beyond a standard digital-safety reminder. Department members were told to review accounts for publicly available information, set profiles to private and remove anything that could identify a link to the Department of the Navy or reveal patterns of life. They were also told to report suspicious activity to the Naval Criminal Investigative Service, including being photographed or surveilled, suspicious questioning and any drone sighting.
The new notice fits a wider pattern, but it also sharpens it. In the spring, John Phelan issued a similar warning about cyber operations and urged digital security steps. Cao’s version goes further by telling personnel to hide the military connection itself, a sign that the threat is now seen as moving beyond hacks and into the ordinary online traces people leave behind.
There is still one gap in the warning that matters: Cao said the notice was based on recent events, but he did not say which ones. He called the threat deliberate, and he called the campaign coordinated, yet the specific trigger is left out of the public message. That omission does not weaken the advice. It makes the advice feel urgent, because the force is being asked to lock down its digital footprint before the next incident becomes the next lesson.
The broader backdrop is a military already consumed with digital security and surveillance during the Iran war. Earlier this month, publicly available Strava data was said to have revealed troops’ and contractors’ routes and habits, including sites in Bahrain and Jordan, and in December U.S. Central Command told troops to turn off geolocation services and review privacy settings on their devices. The pattern is plain: what starts as a fitness app, a photo or a public profile can become intelligence. For sailors and Marines, the next step is simple and immediate — make the accounts private, strip out identifying details and report anything that looks like someone is watching.
