ANSSI: switch off your smartphone regularly to counter sophisticated attacks

Regularly switching off your smartphone can help protect it from sophisticated attacks. ANSSI advises doing this properly: turn the device off and then back on, rather than using the restart function.

If you value your personal data, you should switch off your smartphone at regular intervals. For instance, the NSA recommends restarting smartphones every week. This easy step does not offer 100% protection against sophisticated cyberattacks. However, it adds another layer of defence by making life more difficult for hackers targeting a smartphone.

Sophisticated attacks typically rely on exploiting several vulnerabilities. When a device is switched off and then switched back on, a hacker may have to repeat the entire exploitation process. However, if you restart a smartphone for security reasons, it is better to do so correctly by powering it down and then turning it back on, instead of selecting the restart option.

This is, at any rate, what ANSSI states in a set of recommendations for the general public. “Switch your phone off and then back on regularly rather than using the ‘restart’ function, to counter certain spyware programs that can simulate a phone restart in order to deceive the user,” the agency says.

ANSSI recommendations: updates, Wi-Fi and smartphone security

Alongside its advice to perform a proper smartphone restart, ANSSI also recommends updating devices systematically and as quickly as possible. These updates include operating-system patches for vulnerabilities that hackers may exploit.

For Android devices, the agency also advises disabling the smartphone’s Wi-Fi, Bluetooth and NFC features whenever they are not in use. Location services should likewise be switched off as soon as they are no longer needed. For iOS users, ANSSI recommends turning off location services in Settings to ensure a “real shutdown”, rather than disabling them through Control Centre.

Regarding apps, the agency recommends uninstalling or archiving those that are not used. While some people do this to free up storage space, ANSSI says that removing these apps helps reduce the attack surface.