"Why the US still won’t require SS7 fixes that could secure your phone" (2019) https://arstechnica.com/features/2019/04/fully-compromised-c...

  the group:

    - dragged its feet on resolving SS7 security vulnerabilities 
    - repeatedly ignored input from DHS technical experts
    - [identified] best practices.. using different filtering systems
    - [but] pushed.. to rely on voluntary compliance