More mail madness?

[Phillip Hallam-Baker <[e-mail]>]

This is a security issue certainly, but it is a particular type of issue
that arises from attempting to analyze the security of a large and complex
system built from parts whose interactions as so complicated that they are
never likely to be sufficiently understood.

https://efail.de/

Basically the attack is to create a new multipart MIME message and sandwich
the ciphertexts we wish to break between chunks of HTML with a URL
reference to a web server we control.

This sort of attack could be devastating in certain situations.


The other attack they describe, the CBC gadget attack is one that I have
already been using a control against. I use a key derivation function to
calculate IVs rather than passing them in-band. I started doing this
because it cleans up the message flows a lot but it also turns out to have
security advantages.