Mobile network infrastructure at growing risk from cyber attack

4G mobile communications networks are increasingly vulnerable to cyber intrusion, according to a new report from a Federal Communication Commission advisory group.

The attack vector, which targets the Diameter signaling protocol used to move traffic on 4G networks, hasn't been successfully exploited yet, according to Travis Russell, chair of the FCC's Communications Security, Reliability and Interoperability Council's working group on network reliability and security risk reduction. But he said mobile phones and the networks that support them are drawing increasing attention from bad actors.

Russell submitted the report at a March 28 CSRIC meeting, where the committee approved it. CSRIC advises the FCC on optimal security and reliability for U.S. communications systems, including telecommunications, media and public safety.

In the report on threats to the 4G's Diameter protocol, Russell called it "the SCADA for telecommunications networks." SCADA, short for Supervisory Control and Data Acquisition systems, refers to industrial control systems used by many industries, including power and water infrastructure providers. Vulnerabilities in those systems, often designed before the connections to the public internet became commonplace, have become notable targets for hackers.

The vulnerabilities of Diameter, Russell reported, are very similar to those discovered in the older Signaling System 7 protocol that supports older wired and wireless networks.

SS7 and Diameter are crucial support protocols that undergird wireline and wireless networks' infrastructures globally, allowing communications devices on those networks to exchange calls and text messages. Diameter is associated with 4G wireless networks.

Breaches of the protocol can allow interception of voice, text and data and tracking of users, just as SS7 vulnerabilities can, said Russell.

"We haven't seen attacks in the wild" on Diameter, he said, even though some vendors have reported them.

Mobile network security provider Adaptive Mobile reported earlier this year that it had detected increasingly sophisticated attacks on the wireless Diameter protocol.

Russell contested such reports. "There have been no real attacks," he said, adding that some vendors are seeing "suspect traffic," which isn't an actual attack. "We've seen some experimentation," he said.

Attackers, he said, target SS7 and Diameter because they are both weak links in mobile networks, allowing outside traffic to "roam" between competitor or contiguous networks. They are meant to allow traffic to flow between networks, making them natural targets.

Information sharing among mobile service providers, equipment makers and the federal government is critical to preventing exploitation of Diameter and 4G networks, said Russell. However, just as with SCADA systems and other infrastructure providers, that sharing is not as easy as it sounds.

"The industry is reluctant to share breach information," said Russell, who is also director of telecommunications cybersecurity at Oracle Communications. "We need to fix that problem."

Additionally, the report tapped the federal government to more quickly declassify threat information for industry consumption. The Department of Homeland Security and other federal agencies "need to engage with industry and share threat intelligence," he said.

The report also called on mobile operators to do more network monitoring and analysis; practice more IT-like cyber hygiene; look more closely at peer networks they connect with, as well as adopt Global Systems for Mobile Communications best practices to secure Diameter interconnections.