Slashdot Mirror
Attention PGP Users: New Vulnerabilities Require You To Take Action Now (eff.org)
A group of European security researchers have released a warning about a set of vulnerabilities affecting users of PGP and S/MIME. From a report: EFF has been in communication with the research team, and can confirm that these vulnerabilities pose an immediate risk to those using these tools for email communication, including the potential exposure of the contents of past messages. The full details will be published in a paper on Tuesday at 07:00 AM UTC (3:00 AM Eastern, midnight Pacific).
In order to reduce the short-term risk, we and the researchers have agreed to warn the wider PGP user community in advance of its full publication. Our advice, which mirrors that of the researchers, is to immediately disable and/or uninstall tools that automatically decrypt PGP-encrypted email. Until the flaws described in the paper are more widely understood and fixed, users should arrange for the use of alternative end-to-end secure channels, such as Signal, and temporarily stop sending and especially reading PGP-encrypted email. Further reading: People Are Freaking Out That PGP Is 'Broken' -- But You Shouldn't Be Using It Anyway (Motherboard).
In order to reduce the short-term risk, we and the researchers have agreed to warn the wider PGP user community in advance of its full publication. Our advice, which mirrors that of the researchers, is to immediately disable and/or uninstall tools that automatically decrypt PGP-encrypted email. Until the flaws described in the paper are more widely understood and fixed, users should arrange for the use of alternative end-to-end secure channels, such as Signal, and temporarily stop sending and especially reading PGP-encrypted email. Further reading: People Are Freaking Out That PGP Is 'Broken' -- But You Shouldn't Be Using It Anyway (Motherboard).
Isn't this supposed to be a peer reviewed protocol that was guaranteed to be secure? How long has this program existed? Holy shit.
In other news, lock picks can be used to open up your model of door lock. We advise you to remove all door locks from your door until a lock pick proof lock can be engineered and installed.
The problem is the clients decrypt, then process any external requests for content. So if you can re-send an encrypted email with an external content request added to it, the client will happily decrypt then send the content request with your precious decrypted content. If you globally disable fetching any external content you don't have to worry. The encryption protocols all work fine, it is the behavior of the clients after the decryption that is the problem. So S/MIME would be affected too, or potentially any other encryption tool. Refusing to load any external content under any circumstances is good advice anyway.
This posting is provided 'AS IS' without warranty of any kind, implied or otherwise.
PGP is broken now? It's only had fairly infrequent and minor issues over time. If this is broken now, then it's the final sign that anyone who thinks computers can be secured is wrong. If you want something secure, write it down in a notebook. It'll be about 100x more secure than putting it on a computer simply by not being networked. Even if someone steals and reads your notebook it's better than someone having it on their phone (or PGP, now I guess) for the ENTIRE WORLD to come along and steal. Computers are great for games, everything else is debatable.
then why are you using PGP? It is only used by criminals and the like.
Yes, indeed, some advice there. Because there is some potential for bad actors to possibly decrypt some of the PGP encrypted messages, if said messages include HTML with links to 3rd party sites (which your email client must display automatically), you need to **completely disable** email encryption. Then all of your email becomes clear text and, fully readable by anyone without effort, and thus you are completely safe from that vulnerability. SMH.
That wonderful advice is brought to you by researchers in no way sponsored by NSA or any other 3 letter agency.
For those worried - make sure your email client does not automatically display any embedded HTML links (or, better yet, just turn off HTML formatted email). I believe this is the default for Enigmail encrypted email anyway. Use plaintext, and you are as safe as cryptography allows. (I believe Enigmail authors posted a message to that effect).
I'm no security expert, but allowing HTML mail to arbitrarily download embedded graphics in a mail client is just dumb. From my reading of the articles, doing that doesn't disable the problem, but keeps the information from escaping back to the malicious parties. This is a mail client problem triggering PGP to decrypt, then allowing the information to escape through embedded graphics, not a fundamental problem in PGP itself. Turning off HTML mail support at the client and just taking the text representation of the message looks like it completely defeats the hack. Tell me if I'm wrong.
PGP and S/MIME. (!?) Thunderbird and Apple Mail and Outlook. Weirdly, they don't mention GnuPG by name but it is strongly implied ("tools that automatically decrypt PGP-encrypted email").
It looks like a bunch of things that seemingly share no code, unless it's some fundamental library or something that got copied a lot. Maybe a buffer overflow in some shared RSA or DH decryption library?
From https://lists.gnupg.org/piperm... :
> 1. This paper is misnamed.
Indeed
> 2. This attack targets buggy email clients.
Exactly
> 3. The authors made a list of buggy email clients.
Well said.
The MUA should not allow *any* utilization of HTTP when rendering a HTML E-mail. Any form of doing that is a serious mistake. Not only because of what is reported here, but also because that way *that* use of HTTP will allow spammers to identify when you open the E-mail. They use that to know if your E-mail adress is still alive.
Serious MUAs don't do this without user consent. Most HTML components even have a explicit offline mode exactly for that reason. Meaning that they won't automatically go online and fetch things like the src url of an IMG.
Any MUA that does this without user consent is completely and utterly wrong. Especially in a security sensitive context. This is something most MUA developers know about and if not, should know.
What might be common sense for us is certainly not for newcomers to PGP or those being made to use PGP in a corporate environment as part of a 'best practice'
when you're sending a PGP message, it needs to be plaintext. HTML is simply too dangerous to be disarmed in every conceivable application. This means your email messages should be read in plaintext for PGP.
I also think the EFF is a bit paranoid in issuing a 'full stop' to using PGP until this is fixed. At worst, you should send a link to the PGP document you'd like the user to read (in plaintext of course.)
Good people go to bed earlier.
Sounds like just what the spies would like you to do to gain temporary access to most communications that used to be encrypted, while disabling some of them...
In Soviet Washington the swamp drains you.
Seriously - there’s no good reason for an email which is important enough to encrypt to include html or other “rich formatting” anyway. Just turn it all off.
#DeleteChrome
I only wish I were using PGP. I can't get others to take encryption seriously enough to deal with the hassle of using it.
Here's to the day it is baked into mail programs in such a way that my program will send a query to public registry or their program and gets their public key just by checking a box before sending an email (or make it the default). But most importantly, mine and their keys were generated whether or not we ever use them. Yeah, there's still man in the middle weaknesses. But it's better than nothing. You'd be able to send Grandma an encrypted email (and maybe visa versa) without her even knowing diddly about encryption.
PGP is broken now? It's only had fairly infrequent and minor issues over time. If this is broken now, then it's the final sign that anyone who thinks computers can be secured is wrong. If you want something secure, write it down in a notebook. It'll be about 100x more secure than putting it on a computer simply by not being networked. Even if someone steals and reads your notebook it's better than someone having it on their phone (or PGP, now I guess) for the ENTIRE WORLD to come along and steal. Computers are great for games, everything else is debatable.
PGP is not broken. The way a few bad email clients are using it is broken. If you are not using Thunderbird you are safe with PGP. While S/MIME is comprised in every email client except modern Outlook, KMail, and mutt.
We fear that the PGP software stores hiddenly the password of the user in the PGP-encrypted message.
It does not appear only in PGP, it includes too SSL, TLS, etc.
By example, if the pure encrypted message occupies 10000 bytes then it will include 200 bytes somewhere hidden for the resulting 10200 bytes of the final encrypted message.
I request a new investigation to this fear.
No. PGP is probably fine. It's that some email clients with HTML email enabled and automatic decrypt enabled open an attack vector for some reasons. The EFF promises the details will be coming soon.
I also think the EFF is a bit paranoid in issuing a 'full stop' to using PGP until this is fixed. At worst, you should send a link to the PGP document you'd like the user to read (in plaintext of course.)
The EFF said no such thing; they recommended uninstalling or disabling widgets that *automatically* decrypt in the MUA.
>Immediately disable and/or uninstall tools that automatically decrypt PGP-encrypted email!
So to fix this, just disable HTML mail and use plain test email. Right?
PGP is not broken as crypto.
Either stop PGP from automatically decrypting, and transfer the encrypted text to PGP for decrypt outside the mail client.
OR, disable html in the mail client, use plain text mail (as I think Snowden recommended years ago).
No. You should read the first link.
This is all situations where the simply act of reading an email causes the mailreader to send a request for an external resource, i.e. html emails. Everyone who cares about security already told their mailreaders to stop doing shit like that back in the 1990s. We're talking about a situation where people already have a problem even if they're not using PGP.
My understanding of this is that it applies only to HTML email - if you are using S/MIME and PGP/GnuPG with text-only emails, you should be fine. So why are EFF calling for disabling all PGP and GnuPG?
Finding God in a Dog
Not..
This vulnerability affects those who have no idea how to use encrypted emails. HTML is not to be used in encrypted emails, neither is external references. In fact anyone who is versed in the secure use of email has any and all external references disabled. I do not care for your fancy font or for the background wall paper, If you refuse to attach any pertinent images directly to the email then they are not worth my time. Email is meant to be used as a direct method of communication, only the relevant portions need to be included and font and color are not relevant.
Personally i blame Microsoft for trying to get the masses to adopt email, if they had just left well enough alone then we wouldn't have half of the problems we do today.
In other words, disable HTML rendering in your email client, and check for other external referencing stupidity it might have. All of which shouldn't be in your client in the first place. So get a better client.
Which again means that the problem isn't in PGP/GPG, and the "security" "researchers" are much busier drumming up hype than they're doing useful work. Which is par for the course in s'kiddie-land. But we already knew that too, of course.
If you have nothing to hide... then why are you using PGP? It is only used by criminals and the like.
Ha, ha.
But seriously. If you have nothing to hide, do all your communication with your bank, mortgage holder, broker, 401(k) administrator, and doctor solely by postcard. And take the shades off your windows.
Law-abiding people have PLENTY to hide. And they have a RIGHT to hide it. The Fourth Amendment, among other parts of the constitution, explicitly recognizes this, and the Supreme Court has issued a ruling making explicit and binding an easy-to-understand "Right to Privacy" interpretation of a combination of several pieces of the Constitution.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Draft of the paper to be released tomorrow here: https://efail.de/efail-attack-paper.pdf
It's going to impact all 15 people in the world using PGPed email!
Either some didn't read the entire article or don't understand the need for authenticated encryption.
The issue the EFF is concerned about is that the OpenPGP spec doesn't mandate authenticated encryption and doesn't specify what to do if authentication fails.
The authentication tag could be as simple as the HMAC of the encrypted message using the symmetric key as the HMAC "secret". Attackers can't create provide a modified message that could be authenticated without knowing the shared key.
Have the minimum AES mode be GCM or other AEAD encryption modes such as ChaCha20-Poly1305.
The standard needs at least two new SHALLs 1) All encryption modes shall be AEAD. 2) Decryption process shall immediately stop if authentication fails and no part of the message is presented to the user.
The EFF is looking to advise dummies (ie. average Joe/Jill/Zilla who doesn't know anything about what they're doing on a computer on average). They want to spread info that will work in securing things without it being too hard for people to actually do.
The more in-depth reasoning and actions will always be sought out by anyone who *isn't* that kind of user.
https://lists.gnupg.org/piperm...
PGP is broken now? It's only had fairly infrequent and minor issues over time. If this is broken now, then it's the final sign that anyone who thinks computers can be secured is wrong. If you want something secure, write it down in a notebook. It'll be about 100x more secure than putting it on a computer simply by not being networked. Even if someone steals and reads your notebook it's better than someone having it on their phone (or PGP, now I guess) for the ENTIRE WORLD to come along and steal. Computers are great for games, everything else is debatable.
PGP is not broken. The way a few bad email clients are using it is broken. If you are not using Thunderbird you are safe with PGP. While S/MIME is comprised in every email client except modern Outlook, KMail, and mutt.
If you are using Thunderbird and you have disabled loading remote content in messages (which you should be doing anyway) then this issue (which relies on automatic execution of embedded remote URLs) won't affect you. HTML emails are the real problem here.
And really has not much to do with PGP/GnuPG either, it is about the insane HTML integration in email software that can leak data if external resources are loaded automatically and, apparently, your email is decrypted automatically. If you have either of these, your security has gone out of the window long before the present issue was discovered. Also seems to require a broken MIME parser. Hence this is an issue with mailers, not with PGP/GnuPG (or rather the OpenPGP format). Pretty much the same screw-up by email software makers also affects S/MIME, only it suffers from missing authenticated encryption in addition.
Bottom line, a sane set-up that only renders HTML (or refuses it completely like I used to, these days I convert it to text with lynx), but does not fetch/execute anything should be safe from this. And yes, you should definitely use PGP/GnuPG, despite what some people say.
The other bottom line is that many people making email software have really, really screwed up here. The makers of PGP/GnuPG have not.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
PGP is very much _not_ broken. Some wannabee mail software is badly broken in how it handles HTML, MIME and PGP integration. This is also not a surprise at all. There is a reason many of us still use mutt or elm or the like at least for encrypted email.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
Auto decryption is convenient but makes the system weaker.
I do this and I don't even use PGP. It's like a built in no-script feature as far as I'm concerned. Only loads local stuff and then I just go to whatever website the email is about. Don't need to click links in emails.
PGP is not broken. Look it's really simple kids, stop using software that does stupid things like automatically opening attachments. You've been warned for literally decades.
Any sane IT department should be disabling at the very least, js in emails. Preferably BAN HTML period though I s'pose "basic" HTML is a middle ground.
The headline should be "outlook users still click on emails".
The more fucked up thing about this is with S/MIME and CA certs that are trusted to execute CODE. It's not an attack surface limited to PGP though.
I am surprised the EFF would participate in this circle jerk. This has nothing to do with encryption. This is one of the great pieces of yellow journalism of our time, and I'm amazed Slashdot would perpetuate it. Shame on you...
I have always disabled html in my email program.
I use Thunderbird, html is disabled, remote content is disabled, I have thoroughly gone through it's about:config, I only connect to my ISP with port 995 and 465, and I run Thunderbird in a firejail. I have also deleted many of it's trusted certificate providers.
I use the Enigmail plugin and do not automatically decrypt.
Is there anything else to be done to secure this?
The word "he" is gender neutral.
The word "she" is feminine.
Also, we all know the hacker ain't a woman.
just convince it....
sudo groupadd mailonly
sudo usermod -a -G mailonly `whoami`
sudo ipset create allowed-mailclntdst6 hash:ip family inet6 timeout 0
sudo ipset create allowed-mailclntdst hash:ip family inet timeout 0
sudo ipset add allowed-mailclntdst6 [imap.provider.tld]
sudo ipset add allowed-mailclntdst6 [smtp.provider.tld]
sudo ipset add allowed-mailclntdst [imap.provider.tld]
sudo ipset add allowed-mailclntdst [smtp.provider.tld]
sudo ip6tables -I OUTPUT -m owner --gid-owner mailonly -j REJECT
sudo iptables -I OUTPUT -m owner --gid-owner mailonly -j REJECT --reject-with icmp-port-unreachable
sudo ip6tables -I OUTPUT -p tcp -m multiport --dports 143,465,587,993 -m owner --gid-owner mailonly -m set --match-set allowed-mailclntdst6 dst -j ACCEPT
sudo iptables -I OUTPUT -p tcp -m multiport --dports 143,465,587,993 -m owner --gid-owner mailonly -m set --match-set allowed-mailclntdst dst -j ACCEPT
sg mailonly thunderbird