EFail - OpenPGP S/MIME Vulnerability

Mirimir mirimir at riseup.net
Mon May 14 23:14:42 PDT 2018

On 05/14/2018 06:05 PM, Marina Brown wrote:
> On 05/14/2018 07:49 PM, Mirimir wrote:
>> On 05/14/2018 06:48 AM, grarpamp wrote:
>>> 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.
>> Thanks. That's the clearest explanation I've seen.
> Remember the campaign against HTML email ? I do.
> We were right.
> --- Marina

Right, and its evil child, remote content.

I always disable HTML. And fetching of remote content.

And I have since the 90s. I got that from this list :)

It's funny that these exploits depend on both. And that some on HN put
it all on pgp/gpg, arguing that one can't expect users to know this
stuff. By default, Thunderbird does render HTML. But at least it doesn't
fetch remote content. So Thunderbird+Enigmail users should be safe.

More information about the cypherpunks mailing list