[Cryptography] Vulnerability found in PGP.

[Ray Dillinger]

On 05/14/2018 11:00 AM, Natanael wrote:
> The details are already out.
> 
> https://efail.de/


Okay, yeah, it's dumb. Attacker takes your old mail that he wants you to
decrypt for him; manipulates the message using S/MIME to slice & dice it
in parts creating a "fake" message where the message he wants decrypted
is part of a URL inside an encrypted message; sends it to you; and when
your system decrypts it, it goes to auto-fetch that phony URL, which
gives him the plaintext of the original message.

It has always been obvious that the auto-fetch of HTML content is an
unsound security practice.  S/MIME's capability to cut and join messages
at arbitrary boundaries after applying processing (including decryption)
to selected substrings makes it worse.  This subverts most standard
methods of document and protocol design for email use.

				Bear