A group of academics have found three new security flaws in 4G and 5G, which they say can be used to intercept phone calls and track the locations of cell phone users.

The findings are said to be the first time vulnerabilities have affected both 4G and the incoming 5G standard, which promises faster speeds and better security, particularly against law enforcement use of cell site simulators, known as “stingrays.” But the researchers say that their new attacks can defeat newer protections that were believed to make it more difficult to snoop on phone users.

Hussain, along with Ninghui Li and Elisa Bertino at Purdue University, and Mitziu Echeverria and Omar Chowdhury at the University of Iowa are set to reveal their findings at the Network and Distributed System Security Symposium in San Diego on Tuesday.

“Any person with a little knowledge of cellular paging protocols can carry out this attack… such as phone call interception, location tracking, or targeted phishing attacks.”

The paper, seen by TechCrunch prior to the talk, details the attacks: the first is Torpedo, which exploits a weakness in the paging protocol that carriers use to notify a phone before a call or text message comes through. The researchers found that several phone calls placed and cancelled in a short period can trigger a paging message without alerting the target device to an incoming call, which an attacker can use to track a victim’s location. Knowing the victim’s paging occasion also lets an attacker hijack the paging channel and inject or deny paging messages, by spoofing messages like Amber alerts or blocking messages altogether, the researchers say.

That puts even the newest 5G-capable devices at risk from stingrays, said Hussain, which law enforcement use to identify someone’s real-time location and log all the phones within its range. Some of the more advanced devices are believed to be able to intercept calls and text messages, he said.

According to Hussain, all four major U.S. operators — AT&T, Verizon (which owns TechCrunch), Sprint and T-Mobile — are affected by Torpedo, and the attacks can carried out with radio equipment costing as little as $200. One U.S. network, which he would not name, was also vulnerable to the Piercer attack.

We contacted the big four cell giants, but none provided comment by the time of writing. If that changes, we’ll update.

Given two of the attacks exploit flaws in the 4G and 5G standards, almost all the cell networks outside the U.S. are vulnerable to these attacks, said Hussain.  Several networks in Europe and Asia are also vulnerable.

Given the nature of the attacks, he said, the researchers are not releasing the proof-of-concept code to exploit the flaws.

The paper comes almost exactly a year after Hussain et al revealed ten separate weaknesses in 4G LTE that allowed eavesdropping on phone calls and text messages, and spoofing emergency alerts.

You can check the full report from techcrunch .