A high-net-worth crypto executive watched in real-time as $4.2M was drained from their exchange account. Their phone never lost cellular service, they never received an unexpected password reset link, and they still had physical possession of their device. They assumed the exchange had suffered an internal breach.
Our investigation proved otherwise. By auditing the telco's signaling logs, we discovered the attackers didn't need to steal the client's SIM card physically. They exploited inherited flaws in the SS7 (Signaling System 7) protocol—the backbone of global telecom roaming. By purchasing access to a rogue SS7 node on the dark web, the attackers tricked the cellular network into believing the executive's phone was roaming in a foreign country.
The Resolution
The network silently routed all incoming SMS messages containing the 2FA tokens directly to the attacker's server while the victim's phone remained idle. We mapped the rogue node's Global Title (GT) routing data, worked with international telecom authorities to blacklist the node, and migrated the executive board to hardware-backed U2F security keys (YubiKeys), permanently neutralizing SMS-based interception vectors.