API: Bug in method auth.validatePhone
Unknown
Vulnerability Details
The bug is that auth.validatePhone does not validate the parameter "sid". In theory he should be in the format "2fa_$userId_$appId_$hash", but to get the correct result (send SMS/make call) enough only "2fa_$userId_$anyText".
For example, these requests will send a SMS:
https://api.vk.com/method/auth.validatePhone?sid=2fa_23048942_lolka
https://api.vk.com/method/auth.validatePhone?sid=2fa_66748_блаблабла
It turns out that with this endlessly send SMS with the activation code, and to call if the request to add voice=1:
https://api.vk.com/method/auth.validatePhone?sid=2fa_66748_блаблабла&voice=1
There is also another bug. SMS and calls will be carried out in any case, even if the user has disabled two-factor authentication.
// I don't know, are you interested. But there is a bug - I reported.
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- Report ID: 64963
- State: Closed
- Substate: resolved
- Upvotes: 2