A 5G Shortcut Leaves Phones Exposed to Stingray Surveillance

While the distinctions between the types of 5G matter a great deal, there’s no easy way to tell whether you’re on a standalone network just by looking at your phone. Android users can download apps that analyze a device’s network connection and can flag non-standalone mode, but that’s an onerous extra step. And those tools are less common on iOS because of Apple’s app restrictions.

The security benefits you miss while on a non-standalone 5G network extend beyond stingrays. You’re potentially susceptible to tracking, eavesdropping, and so-called “downgrade attacks” that push target devices onto older, more vulnerable data networks like 3G. And none of this gets communicated to mobile data users, despite enhanced security features being a key 5G selling point.

The inherent challenge of implementing a massive infrastructure overhaul is the key issue, says Syed Rafiul Hussain, a mobile network security researcher at Pennsylvania State University. Even when 5G standalone mode is deployed in most places, he says, carriers will still run parallel 4G and 3G infrastructure as well that could continue to enable some stingray attacks. 

“As long as we need seamless connectivity, continuous connectivity, we’ll need backward- compatibility using 4G,” he says. “4G stingray attacks, downgrading, man-in-the-middle attacks—those will exist for years even though we have 5G. And trying to move away from non-standalone mode to standalone mode everywhere will take some time.”

So far 90 network operators in 45 countries have committed to making the switch to standalone mode, says Jon France, head of industry security at the telecom standards body GSMA.

“The full picture, the full protections of 5G security come over time and do require the standalone to gain full benefit,” he says. “We’re seeing the initial deployments which are already bringing the core benefits of low latency, high data transfers through the non-standalone method. That still has a 4G core in it, it’s the brain of the network, and until we get to a 5G brain in standalone mode we won’t get all of the security benefits.”

The industry can’t languish in non-standalone mode, says SINTEF Digital’s Borgaonkar. He suggests that smartphone vendors be required to build in options so users can set which types of mobile data networks they want their phone to connect with. Similar to roaming options, you could turn 2G or 5G non-standalone mode or any other iteration off most of the time when you don’t want to risk being unintentionally bumped onto it.

“As the end user I don’t have any option to only get 5G standalone mode,” Borgaonkar says. “If 2G is not secure why can’t I stop my phone from connecting to 2G? There is no requirement or coordination among the vendors about giving users these options—giving them the freedom to choose privacy.”


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