[HN Gopher] Ask HN: How do I protect myself against SIM swap att...
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       Ask HN: How do I protect myself against SIM swap attacks?
        
       I am on T-mobile in the US if that helps.
        
       Author : benrapscallion
       Score  : 31 points
       Date   : 2021-12-30 16:14 UTC (6 hours ago)
        
       | alphabettsy wrote:
       | https://www.t-mobile.com/support/plans-features/account-take...
        
         | kmos17 wrote:
         | in my experience it's pure PR bs with no teeth in response to
         | public pressure. Getting past the code verification is trivial
         | in stores. Employees do not enforce verification at all or even
         | when they do a decent fake id would easily defeat it since
         | tmobile doesn't bother sending a 2fa verification to your
         | device.
        
           | alfu wrote:
           | Yes, I listened to a podcast that describes an attacker
           | getting access even though the victim's account had a PIN
           | (https://darknetdiaries.com/transcript/97/):
           | 
           | >MILES: [MUSIC] They were able to get ahold of T-Mobile and
           | manipulate their way in through either doing it in person or
           | doing it over the phone, and convince somebody to change out
           | the SIM for them.
        
       | dookahku wrote:
       | I use Google Fi because the SIM card is attached to my Gmail
       | account where I can use A real 2FA
        
         | toomuchtodo wrote:
         | Does Google Fi support eSIM?
        
           | devoutsalsa wrote:
           | Yes.
        
             | toomuchtodo wrote:
             | Tremendous, thank you!
        
       | CAPSLOCKSSTUCK wrote:
       | One answer I haven't seen mentioned yet is to use a carrier who
       | lacks a physical presence (e.g. many MVNOs). I'm not sure if the
       | MVNO security infrastructure can be circumvented by employees at
       | the source network's physical stores, however. E.g. if I use
       | Boost Mobile, can a Verizon store employee override the PIN I've
       | set?
       | 
       | Of course the best answer is to not rely on SMS or voice call
       | 2FA, but as others point out, some services only support these
       | insecure options.
        
       | ridaj wrote:
       | Use authenticator app for 2FA, not your phone number.
       | 
       | But be really sure you want to do this. The main reason I would
       | not recommend ordinary consumers do this, is that if you lose
       | your SIM (eg, stolen or lost phone), you can go to a mobile phone
       | shop and get a new SIM card issued to you after verifying your
       | identity. With other forms of 2FA, you do not have access to the
       | same real-life-based identity verification service, and it is
       | also essentially the source of SIM-swap risk.
        
         | pkrotich wrote:
         | Authenticator app can also stop working when you migrate to a
         | new phone - a friend got locked out recently after migration.
         | Apparently you need to follow some steps [0]
         | 
         | [0] https://www.alphr.com/transfer-google-authenticator-codes-
         | ne...
        
           | yumraj wrote:
           | You can use Authy and install it on multiple
           | devices/computers
        
           | Zizizizz wrote:
           | Andotp or aegis authenticator are both great open source 2fa
           | apps that let you export and backup your 2fa to cold storage
           | somewhere incase of these situations
        
         | embeng4096 wrote:
         | Yes, ordinary consumers are starting to use TOTP more but still
         | may not be aware of what you pointed out.
         | 
         | To mitigate the risk of losing my 2FA credentials I use the
         | FOSS app andOTP (Aegis is similar, but better UI, from what I
         | hear). It can export your data as both cleartext and encrypted
         | JSON so you can import into a new phone as desired.
        
           | ridaj wrote:
           | I'm aware of solutions that can help prepare for a backup. I
           | don't think most people should trust themselves to handle
           | backup responsibilities. Speaking as someone locked out of an
           | encrypted disk full of old photos that I carefully wrote down
           | the passphrase to on a piece of paper for safekeeping...
           | Since then lost.
        
       | missedthecue wrote:
       | Don't use text messages as 2FA in the first place.
        
         | andrei_says_ wrote:
         | Not up to me in many cases.
        
         | dookahku wrote:
         | That's a good idea but it's not a practical solution because
         | most websites don't give you the choice.
        
       | greatjack613 wrote:
       | I use google voice locked with 2fa like the rest of my google
       | account.
       | 
       | And yes, I have never been rejected from a service for using a
       | google voice number as my 2fa source. Heck, even my google
       | account uses 2fa through the google voice number - as one option
       | :)
        
         | drakonka wrote:
         | I've never even heard of Google Voice and now feel like I've
         | been living under a rock. Could you elaborate on how you use
         | this? For example:
         | 
         | * Do you use the same Google Voice number as your actual Google
         | account phone number, or just for other sites? If the former,
         | how does it work with Google 2FA (ie if you are logged out of
         | Google account I imagine you can't access you Voice number
         | either?)
         | 
         | * Are you concerned with losing access to your Google Voice
         | number if Google decides to ban your account one day? Regular
         | phone numbers seem a bit less nebulous in that phone providers
         | don't seem to just suddenly decide to ban you and your number
         | as much as Google, Amazon, et al. Then again I have no data to
         | back up this impression.
         | 
         | * What made you pick Google Voice over another VoIP option?
         | 
         | * Do you worry about Voice going away with Google Fi?
        
         | Sinema wrote:
         | Not 2FA per se but Google Voice numbers do not work for certain
         | services at all. Zelle is a recent example I ran into but I've
         | had others before that wouldn't accept it or would accept it
         | but fail silently.
        
       | jrootabega wrote:
       | Have a separate sim/phone dedicated to 2fa.
       | 
       | Send test sms to yourself at least twice a day
        
         | b3morales wrote:
         | Could you elaborate? What makes the secondary one more secure
         | than the first one?
        
           | dmitrygr wrote:
           | Nobody knows about it. Sim swappers will attack your number.
           | The one they know.
        
             | jrootabega wrote:
             | They may be able to bribe phone company employees to look
             | you up by name, but you'd at least be blocking one route of
             | compromise
        
               | dmitrygr wrote:
               | Which company? :)
        
               | jrootabega wrote:
               | All of them, probably
        
           | Zircom wrote:
           | Having a separate number/SIM solely for 2fa makes it harder
           | for attackers to know the number they need to initiate a
           | simswap in the first place, since it won't be publicly
           | associated with you the same way your normal phone number is,
           | like being listed on your LinkedIn or resume, or obtained
           | from a social media or other account info leak, or able to be
           | socially engineered or phished out of friends/family.
        
             | b3morales wrote:
             | All good points, thank you.
        
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       (page generated 2021-12-30 23:01 UTC)