SS7 (Signaling System 7) protocol has some serious flaws, of which the experts have been warning for years now. This is something that the cellphone networks are using in order to communicate, and it turned out to be very vulnerable.
The flaws in the system can be abused in several different ways, as the researchers have reported, includes redirecting calls and text messages to other devices. And now we even have examples of how this can be used to rob people out of their money.
Germany’s O2-Telefonica has confirmed that several of Süddeutsche Zeitung users were robbed and had their accounts emptied. The criminals who did it apparently exploited SS7 and used a two-stage attack.
Simply said, thieves intercepted two-factor codes that the bank customers were supposed to receive, and then used them to empty their victim’s accounts. Multiple sources have confirmed that these thefts happened during the past few months.
SS7 was created back in the 1980s so that telcos could connect landline and cellular networks and exchange data. Scientists have discovered that this system is flawed, and are repeating it since 2014. They’ve warned that a hacker or a corrupt employee of telcos can use flaws like this and track phones, read and redirect messages, listen to calls and breach users’ privacy in general.
This has now proven to be true, and hackers used the two-factor system to trick banks and transfer the funds between the accounts. They started by spamming victim’s computer with malware and used it to collect the bank account balance and users’ credentials. After that, they would gain access one of the rogue telecommunications providers, and redirect everything that’s sent to the victims phone to the one controlled by them.
The rest of it was easy, the hacker would log into victims online bank account in the middle of the night and transfer the funds. Both the security experts and the politicians were trying to warn telcos of this kind of attacks, but their warnings didn’t do much. The general attitude was that you’d need a telco to pull off an attack like this and that none of the firms would allow someone to use them like that.
Of course, that may have been so back in the 1980s, but now pretty much anyone can get a telco, either by setting it up themselves or by buying a rogue one. A solution was presented – to replace SS7 with 5G, but unfortunately, this also has many security issues, according to the FCC.
Since Germany has quite an influence in Europe, many hope that this might be enough to start fixing the SS7 problems. When it comes to the US, it’s believed that there will be no significant changes until their citizens’ experience a few attacks themselves.