EFail - OpenPGP S/MIME Vulnerability

[grarpamp]

https://efail.de/
https://lists.gnupg.org/pipermail/gnupg-users/2018-May/060315.html
https://efail.de/efail-attack-paper.pdf
https://twitter.com/matthew_d_green/status/995989254143606789
https://news.ycombinator.com/item?id=17064129
https://www.eff.org/deeplinks/2018/05/attention-pgp-users-new-vulnerabilities-require-you-take-action-now
https://arstechnica.com/information-technology/2018/05/critical-pgp-and-smime-bugs-can-reveal-encrypted-e-mails-uninstall-now/


The EFAIL attacks break PGP and S/MIME email encryption by coercing
clients into sending the full plaintext of the emails to the attacker.
In a nutshell, EFAIL abuses active content of HTML emails, for example
externally loaded images or styles, to exfiltrate plaintext through
requested URLs. To create these exfiltration channels, the attacker
first needs access to the encrypted emails, for example, by
eavesdropping on network traffic, compromising email accounts, email
servers, backup systems or client computers. The emails could even
have been collected years ago.