SMS-fr

De xtof lifedesign


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SMS, t(e)xt messaging, or t(e)xting is a way of sending short messages over cell phones which is unfortunately often used and recommended by silos as a second factor and password resets, despite being highly insecure and a known enabler of account hijackings.

Criticism

Insecure Account Recovery

Insecure Second Auth Factor

  • 2018-08-01 We had a security incident. Here's what you need to know.
    • "Already having our primary access points for code and infrastructure behind strong authentication requiring two factor authentication (2FA), we learned that SMS-based authentication is not nearly as secure as we would hope, and the main attack was via SMS intercept. We point this out to encourage everyone here to move to token-based 2FA."
  • 2018-07-17 Motherboard: The SIM Hijackers

    By hijacking Rachel’s phone number, the hackers were able to seize not only Rachel’s Instagram, but her Amazon, Ebay, Paypal, Netflix, and Hulu accounts too. None of the security measures Rachel took to secure some of those accounts, including two-factor authentication, mattered once the hackers took control of her phone number.

    Emphasis added.

Silo Examples

(need screenshots from the nag-ware screens from Apple (iOS 9+ nags you on first start, iOS 10+ nags you continuously in Settings app), Google, Facebook etc encouraging/defaulting you to add your cell phone number for auth / recovery reasons).

Also need screenshots from any services that when you add SMS as a second factor, they default to adding SMS as an account recovery method (1-factor), which actually makes your account *LESS SECURE* than if you would have never attempted to turn on 2FA in the first place.

Apple ID

Apple ID is a silo identity service that is now (all but?) required to use any iOS or MacOS device.

On MacOS, you are prompted by the "Settings" app to associate a phone number that can receive SMS with your Apple ID to "verify your identity":

2017-02-17-macos-2fa-sms-settings-e.png


Instagram

Instagram only allows SMS based MFA and then enables SMS recovery as well thus making your account MORE vulnerable (e.g. to SIM-jacking as documented) than if you had never turned on their MFA.

  • 2018-07-17 Motherboard: The SIM Hijackers

    Certain services, including Instagram, require that users provide a phone number when setting up two-factor, a stipulation with the unintended effect of giving hackers another method of getting into an account. That’s because if hackers take over a target’s number, they can skirt two-factor and seize their Instagram account without even knowing the account’s password.


Twitter

Twitter actually prompts you to add a phone number to your account (if you don't already have one on it) with SMS password reset *as a feature*! They are literally prompting you to make your account *less* secure, while claiming the opposite. WTF.

2017-09-27-twitter-add-sms-pw-reset-prompt.png

Text of prompt reads (emphasis added):

Safeguard your account

Add your phone number now to help ensure that you can log in to Twitter, even if you lose your password


What the prompt really means:

Make your account vulnerable

Add your phone number now to help ensure that anyone pretending to be you to your phone company can log in to Twitter, even without your password

Benefits

When used for it's intended purpose - for notifications that doesn't require security -, SMS can be used as an alternative to push notifications in case there is no data connectivity due to it's extremely compact nature. Services like PagerDuty utilize SMS alerting for monitoring.

See Also