When visiting certain high-risk countries on business, your smartphone activity may be monitored by local intelligence services. From fake cell towers to malicious carrier updates, spies in these countries have a number of ways to install malware on your device through your cellular connection alone. As such, it’s best to assume that your smartphone has been compromised when on foreign soil.

In September 2019, attribution was given to Israel for the IMSI catchers discovered in Washington, D.C. two years earlier, shining light on the prevalence of these types of spying devices. Once used solely by law enforcement as a way of finding the international mobile subscriber identity (IMSI) linked to a criminal suspect’s SIM card for investigative purposes, now just about anyone can acquire or build an IMSI catcher to intercept a target’s communications. With such low barriers to entry, it’s no longer just the bad guys who need to be worried about these devices.

CEO walks out of nondescript office building accompanied by COLLEAGUE. CEO pulls smartphone out of her purse to study a restaurant’s website. Her smartphone’s status bar blinks briefly to indicate a change in cellular connection status.