2018-01-03 19:04 GMT+02:00 Daniel Kahn Gillmor <d...@fifthhorseman.net>: > On Wed 2018-01-03 14:39:55 +0200, Lachezar Dobrev wrote: >> Recently I've been greeted with a red warning every time I try to >> reply to an encrypted message saying: >> >> "Beware of leaking sensitive information - partially encrypted email." >> >> With a Details button that shows a pop-up: >> >> """ >> The message you are editing was partially encrypted. That is, the >> message contains unencrypted and encrypted parts. Some encrypted >> message parts may even be invisible to you. >> >> If the sender was not able to decrpyt the message parts originally, it >> is likely that you only got the email with some surrounding >> unencrypted text in order to make you reveal the encrypted >> information. >> """ >> (the "decrpyt" is a spelling mistake as is) >> >> What does this actually mean, and why does it show on every message >> I try to reply to? >> >> I have checked, and the mail is encrypted with the same two keys >> that the reply is going to be encrypted with: one is mine, the other >> is the one for the original sender. > > This is about CVE-2017-17844. The attack these warnings aim to mitigate > against goes like this: > > * attacker gets a copy of an encrypted message X that had been sent to > you > > * attacker creates a new message Y to you, and embeds encrypted message > X somewhere in the tail of message Y (the long chain of quoted, > attributed text that everyone ignores because top-posting is somehow > the expected norm). > > * you receive message Y, and reply to it (composing a new e-mail to the > attacker). > > * without the warning, it's likely that enigmail will decrypt the > quoted message and place the cleartext in the new reply message. > > > However, it sounds like you're seeing this warning trigger on every > e-mail reply, which seems unlikely to be the intended situation. > > What do your inbound e-mails look like? how are they structured? are > they PGP/MIME, or inline PGP? if they're inline PGP, is there a lot of > text around the encrypted blob? > > --dkg
Hm, that does make sense. I made a test: sent myself a pair of PGP/MIME and a pair of Inline-PGP messages (one with signature, another unsigned). Trying to reply to the PGP/MIME message works as expected. Trying to reply to the Inline-PGP was met with the "Beware..." warning. I also noticed that most my peers are using Inline-PGP 'cause android... I also noticed, that when cancelling the replies to the Inline-PGP messages Thunderbird asks to save the draft even with no new content, while cancelling the replies to the PGP/MIME message goes through. I suspect it is due to the way Inline-PGP messages work (the content is decrypted in-place). The Inline-PGP mail seems to be really blank: """ To: obfuscated From: obfuscated Subject: Test Message-ID: <obfuscated> Date: Thu, 4 Jan 2018 15:15:55 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: bg Content-Transfer-Encoding: 8bit -----BEGIN PGP MESSAGE----- Charset: utf-8 hQIOAxxQ0nrmqQMHEAf7BkQcd2+kZmXLrDOkUPpHf41/P3cssK4aslN+yuMPEQg5 ... stripped 16 lines ... cBrNYUYb =cT46 -----END PGP MESSAGE----- """ If I understand correctly this is something I should get accustomed with. _______________________________________________ enigmail-users mailing list enigmail-users@enigmail.net To unsubscribe or make changes to your subscription click here: https://admin.hostpoint.ch/mailman/listinfo/enigmail-users_enigmail.net
