evidence: The universal adoption of smartphones, as well as social media, has revolutionized the dynamics of surveillance, especially in theater. Social media requires few intermediaries, meaning that members of the armed forces can—and do—use smartphones to participate in online dialogue without oversight. More data—such as locations, and information about habits, health, relationships, religious beliefs, and more—is being generated and shared than ever before. Although militaries often instruct soldiers in the field not to utilize personal phones, the rules are regularly ignored. [...] Militaries need to adapt to the realities of an era in which smartphone and social media use by soldiers is inevitable. Proactively understanding specific vulnerabilities associated with the ecosystem of data collected by apps running on soldier’s smartphones could help identify which apps are particularly good (or particularly bad) at protecting data that might be of interest to military adversaries. [...] Despite their troubling vulnerabilities, smartphones on the battlefield do enable immense tactical opportunities. A key challenge for modern militaries lies in maximizing the benefits of the extraordinary communications and computational capacity of current and next-generation smartphones while sufficiently mitigating the equally extraordinary cyber and intelligence risks involved in their use.