The flaws in the signalling system 7 (SS7) — a telephone signal system developed in the 1980s, used to set up most of the world's telephone networks — are set to be reported at a Hacker conference in Hamburg later this month, according to the Washington Post, further highlighting the lack of security and vulnerability of existing cellular security systems.
The flaws, discovered independently by German researchers Tobias Engel and Karsten Nohl, were found to be related to functions built into SS7, which were designed to allow customers to stay connected to a particular service.
Researchers found that anyone who gained access to a mobile network then had the ability to listen in on mobile phone calls and decode text messages.
Although efforts are being made to improve global security systems to protect people against eavesdropping, experts note that it will take many years for all of the outdated systems to be replaced, meaning that even those mobile providers with upgraded security will be vulnerable to hacking when they contact people on outdated networks.
This means that hypothetically, a mobile service provider in Africa, Asia or the Middle East could be used by hackers to infiltrate and listen into calls from networks in the UK, Europe or the United States — or vice versa.
"It's like you secure the front door of the house, but the back door is wide open," Tobias Engel, one of the German researchers who made the discovery told the Washington Post.Security systems for a different time
Dr James Irvine, reader in wireless communications at the University of Strathclyde notes that it isn't a complete surprise to find flaws in SS7 security protocols, given it was developed in the 1980s.
"The problem is that a lot of these protocols were designed when everyone assumed that everything within the network was secure; that it was a closed network and nobody could get up to any devious activities within the network. So, you didn't have to worry too much about authenticating the data that was going backwards and forwards. SS7 has some security features in it, but if you can get into the network, then you can send SS7 controls to get the call redirected. So you could effectively manage to route the call, via yourself so you can listen into it."
Dr Irvine noted that the increased knowledge of ‘hackers' and the affordability of adequate technology has further exposed the outdated nature of SS7's security features."It's not designed for the world we live in at the moment. SS7 was designed when you had national telecomm operators talking to other national telecomm operators, and you needed tens of hundreds of millions of dollars to set up a network, or even a switching centre within a network. But now we're living in a situation where, with a PC and a little bit of radio hardware, you can emulate a GSM (Global System for Mobile Communications) network.Who is listening in?
The revelations have sparked concerns that flaws in the mobile network systems are being exploited by intelligence agencies to listen in on calls and decode messages.
The Edward Snowden revelations have led many industry experts to note the sophisticated surveillance operations of governmental intelligence agencies like Britain's GHCQ and the American NSA.
Despite the worries over any potential intelligence agency phone hacking, Dr Irvine believes there are more serious concerns following the revelation of SS7's security flaws.
"If you operate a telecomm network, in most countries, you have to include lawful interception. So, security agencies already have the facilities to tap into calls. The real worry is not so much the security agencies being able to tap into calls, because there is at least some sort of oversight over the security agencies. The real worry is we're now getting computing power and communications technology to a stage where non-security agencies can pretend to be networks, or get themselves into networks and make use of these vulnerabilities, so I think that's where the real risk lies."
As the battle for surveillance becomes an increasingly international game, played by both governments and anonymous hackers, there is a growing push for greater mobile privacy and security.
And although efforts are being made to increase security measures, the latest revelations about flaws in mobile security systems have highlighted that there is still a lot of work to do to keep our phone calls truly private.
