RICHMOND, Va. — As a member of the secretive Senate Intelligence Committee, Sen. Angus King has reason to worry about hackers. At a briefing by security staff this year, he said he got some advice on how to help keep his cellphone secure.
Step One: Turn off phone.
Step Two: Turn it back on.
That’s it. At a time of widespread digital insecurity, it turns out that the oldest and simplest computer fix there is — turning a device off then back on again — can thwart hackers from stealing information from smartphones.
Regularly rebooting phones won’t stop the army of cybercriminals or spy-for-hire firms that have sowed chaos and doubt about the ability to keep any information safe and private in our digital lives. But it can make even the most sophisticated hackers work harder to maintain access and steal data from a phone.
“This is all about imposing cost on these malicious actors,” said Neal Ziring, technical director of the National Security Agency’s cybersecurity directorate.
The NSA issued a “best practices” guide for mobile device security last year in which it recommends rebooting a phone every week as a way to stop hacking.
King, an independent from Maine, says rebooting his phone is now part of his routine.
“I’d say probably once a week, whenever I think of it,” he said.
Almost always in arm’s reach, rarely turned off and holding huge stores of personal and sensitive data, cellphones have become top targets for hackers looking to steal text messages, contacts and photos, as well as track users’ locations and even secretly turn on their video and microphones.
“I always think of phones as like our digital soul,” said Patrick Wardle, a security expert and former NSA researcher.
The number of people whose phones are hacked each year is unknowable, but evidence suggests it’s significant. A recent investigation into phone hacking by a global media consortium has caused political uproars in France, India, Hungary and elsewhere after researchers found scores of journalists, human rights activists and politicians on a leaked list of what were believed to be potential targets of an Israeli hacker-for-hire company.
The advice to periodically reboot a phone reflects, in part, a change in how top hackers are gaining access to mobile devices and the rise of so-called “zero-click” exploits that work without any user interaction instead of trying to get users to open something that’s secretly infected.
“There’s been this evolution away from having a target click on a dodgy link,” said Bill Marczak, a senior researcher at Citizen Lab, an internet civil rights watchdog at the University of Toronto.
Typically, once hackers gain access to a device or network, they look for ways to persist in the system by installing malicious software to a computer’s root file system. But that’s become more difficult as phone manufacturers such as Apple and Google have strong security to block malware from core operating systems, Ziring said.
“It’s very difficult for an attacker to burrow into that layer in order to gain persistence,” he said.
“Adversaries came to the realization they don’t need to persist,” Wardle said. “If they could do a one-time pull and exfiltrate all your chat messages and your contact and your passwords, it’s almost game over anyways, right?”
