Experts have been warning for years about security blunders in the Signaling System 7 protocol – the magic glue used by cellphone networks to communicate with each other.

These shortcomings can be potentially abused to, for example, redirect people’s calls and text messages to miscreants’ devices. Now we’ve seen the first case of crooks exploiting the design flaws to line their pockets with victims’ cash.

O2-Telefonica in Germany has confirmed to Süddeutsche Zeitung that some of its customers have had their bank accounts drained using a two-stage attack that exploits SS7.

In other words, thieves exploited SS7 to intercept two-factor authentication codes sent to online banking customers, allowing them to empty their accounts. The thefts occurred over the past few months, according to multiple sources.

Source: After years of warnings, mobile network hackers exploit SS7 flaws to drain bank accounts