TY  - CHAP
A1  - Müller, Jens
A1  - Brinkmann, Marcus
A1  - Poddebniak, Damian
A1  - Schinzel, Sebastian
A1  - Schwenk, Jörg
T1  - Mailto: Me Your Secrets. On Bugs and Features in Email End-to-End Encryption
T2  - 2020 IEEE Conference on Communications and Network Security (CNS)
N2  - OpenPGP and S/MIME are the two major standards for email end-to-end encryption. We show practical attacks against both encryption schemes in the context of email. First, we present a design flaw in the key update mechanism, allowing a third party to deploy a new key to the communication partners. Second, we show how email clients can be tricked into acting as an oracle for decryption or signing by exploiting their functionality to auto-save drafts. Third, we demonstrate how to exfiltrate the private key, based on proprietary mailto parameters implemented by various email clients. An evaluation shows that 8 out of 20 tested email clients are vulnerable to at least one attack. While our attacks do not target the underlying cryptographic primitives, they raise concerns about the practical security of OpenPGP and S/MIME email applications. Finally, we propose countermeasures and discuss their advantages and disadvantages.
KW  - Cyber Security
KW  - PGP
KW  - S/MIME
Y1  - 2020
U6  - http://dx.doi.org/10.1109/CNS48642.2020.9162218
SP  - 1
EP  - 9
ER  -