I'd add to that that people probably shouldn't treat phones as a significant increase in security, it's not really the out-of-band device that it used to be/was in the 1990s. Today, it basically equates to a second computer and the probability that the second computer is also compromised isn't overly unrealistic. While the focus is rightfully on SMS, I'd basically consider anything that isn't a hardware token to be more or less the same-- although in fairness the specifics of what we're talking about here doesn't include any of the computers involved, which is a different problem.
18.04.2021, 06:21, "Mel Beckman" <mel@beckman.org>:
No, every SMS 2FA should be prohibited by regulatory certifications. The telcos had years to secure SMS. They did nothing. The plethora of well-secured commercial 2FA authentication tokens, many of them free, should be a mandatory replacement for 2FA in every security governance regime, such as PCI, financial account access, government web portals, etc.
-mel via cell
Every SMS 2FA should check the current carrier against the carrier when enrolled and unenroll SMS for 2FA when a number is ported out. BofA and a few others do this.
--
Tim
Anecdotal: With the prior consent of the DID holders, I have successfully ported peoples' numbers using nothing more than a JPG scan of a signature that looks like an illegible 150 dpi black and white blob, pasted in an image editor on top of a generic looking 'phone bill'.