Description
The signature verification routine in the Airmail GPG-PGP Plugin, versions 1.0 (9) and earlier, does not verify the status of the signature at all, which allows remote attackers to spoof arbitrary email signatures by crafting a signed email with an invalid signature. Also, it does not verify the validity of the signing key, which allows remote attackers to spoof arbitrary email signatures by crafting a key with a fake user ID (email address) and injecting it into the user's keyring.
References
- https://github.com/Airmail/AirmailPlugIn-Framework/commits/master
- 20190430 OpenPGP and S/MIME signature forgery attacks in multiple email clients mailing-list
- http://packetstormsecurity.com/files/152703/Johnny-You-Are-Fired.html
- [oss-security] 20190430 Spoofing OpenPGP and S/MIME Signatures in Emails (multiple clients) mailing-list
- https://github.com/RUB-NDS/Johnny-You-Are-Fired
- https://github.com/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.pdf