Hackers can abuse LTE protocols to knock phones off networks

When you travel between countries, the mobile operators that temporarily provide service to your phone need to communicate with your operator back home. This is done over a global interconnection network where most traffic still uses an ageing protocol, called SS7, that's known to be vulnerable to location tracking, eavesdropping, fraud, denial of service (DoS), SMS interception and other attacks.

With the advance of Long-Term Evolution (LTE) networks, some roaming traffic is switching to a newer protocol, called Diameter, that's more secure than SS7 in theory, but which still allows for attacks if it's not deployed with additional security mechanisms.

For example, the Internet Protocol Security (IPsec), a secure communications suite that works by authenticating and encrypting each IP (Internet Protocol) packet, has been standardized for Diameter. But while its implementation is mandatory, its use is optional.