I repeat this on related threads: taking over any US phone number's inbound/outbound SMS traffic with the ability to intercept inbound SMS as well as send SMS originating from a particular number is dangerously easy. It takes one minute, and ALL numbers are vulnerable. Worse, there is no fix for this. Never ever use SMS for authentication, or sensitive communication of any kind.

I believe this is being exploited on a regular basis and people just have no clue. This is likely used for anything from gaining access to email accounts to insider trading to political leverage to who the heck knows what else.