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I've been doing this to get by SMS based two factor in pen tests for years. The only time it didn't work is when I'd forgotten part of the auto process so I'd h

by nikcub 10y ago

I've been doing this to get by SMS based two factor in pen tests for years. The only time it didn't work is when I'd forgotten part of the auto process so I'd hang up and try again Because support teams aren't coordinated with call attempts you can essentially brute force the process Also the online portals for number transfer are notoriously weak. There was one MVNO i used for years because their website did no server side auth and I could transfer numbers to new SIMs at will SMS as an authentication transport is beyond useless - nobody should be implementing it

gst 10y ago
Does the provider that currently holds the number need to release the number when it's transfered? Or can any random provider port out my number from my current provider?
- nikcub 10y ago
  Most countries have number portability laws now that say the current provider has to release the number. They can't even hold it over an unpaid debt. Worse, a lot of these laws have government SLAs in them that say x% of transfers have to happen within 2-3 hours (usually 90-99%) There is zero incentive from any party to add friction to the process for authentication purposes It really got easy when I noticed the process was automated by a lot of providers a few years ago. I really don't think there was any human oversight on many of these transfers (perhaps a rubber stamp from a cheap offshore pair of eyes for compliance purposes)
  - phicoh 10y ago
    The last time I transferred my mobile number, the telco wanted to have the IMSI as well. Then what my phone reported was not what they wanted, so it took a while to sort that out. But it seems secure enough. It is not easy to get an IMSI for a random phone number.
    - lukego 10y ago
      > It is not easy to get an IMSI for a random phone number This is easy if you have an SS7 network connection. Comparable to the difficulty of resolving a DNS name to an IP address using an internet connection.

by nikcub 10y ago

gst 10y ago

Does the provider that currently holds the number need to release the number when it's transfered? Or can any random provider port out my number from my current provider?

nikcub 10y ago
Most countries have number portability laws now that say the current provider has to release the number. They can't even hold it over an unpaid debt. Worse, a lot of these laws have government SLAs in them that say x% of transfers have to happen within 2-3 hours (usually 90-99%) There is zero incentive from any party to add friction to the process for authentication purposes It really got easy when I noticed the process was automated by a lot of providers a few years ago. I really don't think there was any human oversight on many of these transfers (perhaps a rubber stamp from a cheap offshore pair of eyes for compliance purposes)
- phicoh 10y ago
  The last time I transferred my mobile number, the telco wanted to have the IMSI as well. Then what my phone reported was not what they wanted, so it took a while to sort that out. But it seems secure enough. It is not easy to get an IMSI for a random phone number.
  - lukego 10y ago
    > It is not easy to get an IMSI for a random phone number This is easy if you have an SS7 network connection. Comparable to the difficulty of resolving a DNS name to an IP address using an internet connection.