The Diameter protocol used within mobile 4G networks for signal processing is vulnerable to a kind of Denial-of-Service (DoS) attacks. This was recently discovered by the experts of network security specialist Positive Technologies.

According to the security experts, the standard Diameter protocol for signal processing is as leaky as a sieve. This protocol for mobile networks takes care of communication and translation between different IP network elements. Specifically, the Diameter protocol within LTE (4G) networks takes care of authenticating and allowing signalling traffic.

The researchers found that the protocol in question is open to simple DoS attacks in particular. This is due to design errors in the Diameter protocol. According to Positive Technologies, many 4G networks check the exact location of a subscriber via GSMA signalling, nor do they confirm the source network of subscriber signalling messages. This makes it easy for attackers to adjust source addresses and carry out DoS attacks like that.

Other attack options

Other types of attacks are also possible, such as bypassing measures to use networks free of charge and fraudulently, and intercepting SMS messages. Errors in the protocol also allow hackers to track subscribers and steal subscriber information. For example, in 89 percent of the cases surveyed, it was possible to pretend to be a roaming partner to send signalling messages asking for a subscriber’s location.

In 81 percent, it was even possible to steal personal information from subscribers. Examples include phone numbers, the status of mobile devices and access point configurations. Here, too, the non-confirmation of user locations played a role in the reception of signalling traffic, according to Positive Technologies.

Important for arrival of 5G

All 4G networks are affected, the researchers continue. This also has consequences for the upcoming roll-out of 5G networks. Many operators are using their existing 4G networks as a basis for the rollout of these super-fast mobile networks. According to the researchers, it is therefore important to tackle this problem seriously and above all structurally, because otherwise the rollout of 5G could be compromised.