Android pin bypass with rate limiting

baluz
1 min readJul 18, 2020

Application pin rate limiting bypass

The bug is in private program .

There is a feature to lock mobile app with pin . But only 3 attempts. If we attempt wrong pin. The app logouts.

But there is a misconfig in this feature. If you enter the pin 2 times. close the app and open the app again you will get another 3 attempts . So the rate limiting bypassed by closing and calling the main activity

You can launch the main activity as many times as you want with adb

while true;do adb shell am start -a android.intent.action.VIEW -n com.redacted/com.redacted.MainActivity;sleep 4;done

while the sleep time you can enter the pin 2 times and again the main activity will be called so you can enter pin again

Impact :- mobile auth pin rate limiting bypassed

No thanks for reading ..!

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