Security News > 2020 > June > Researcher Claims Apple Paid $100,000 for 'Sign in With Apple' Vulnerability
An attacker exploiting the vulnerability could have taken over user accounts on the affected third-party applications, regardless of whether the victim was using a valid Apple ID or not, security researcher Bhavuk Jain explains.
In the second step, the user is provided with the option to share the Apple Email ID with the third-party app.
If the user does not share their ID, a user-specific Apple relay Email ID is generated, and then a JWT that contains this Email ID is created, for the third-party app to log in the user.
"I found I could request JWTs for any Email ID from Apple and when the signature of these tokens was verified using Apple's public key, they showed as valid. This means an attacker could forge a JWT by linking any Email ID to it and gaining access to the victim's account," the researcher reports.
The researcher also claims that Apple has paid a $100,000 bug bounty for the finding, as part of the Apple Security Bounty program.