Language Selection

English French German Italian Portuguese Spanish

Critical PGP Security Issue

Filed under
  • Attention PGP Users: New Vulnerabilities Require You To Take Action Now

    A group of European security researchers have released a warning about a set of vulnerabilities affecting users of PGP and S/MIME. 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.

  • Disabling PGP in Thunderbird with Enigmail

Response from Werner Koch

Subject: Efail or OpenPGP is safer than S/MIME
Date: Mon, 14 May 2018 09:45:51 +0200
From: Werner Koch


Some may have noticed that the EFF has warnings about the use of PGP out
which I consider pretty overblown. The GnuPG team was not contacted by
the researchers but I got access to version of the paper related to
KMail. It seems to be the complete paper with just the names of the
other MUAs redacted.

Given that the EFF suggests to deinstall GpgOL, we know tha it is not
vulnerable; see see

Here is a response I wrote on the weekend to a reporter who inquired on
this problem.

The topic of that paper is that HTML is used as a back channel to create
an oracle for modified encrypted mails. It is long known that HTML
mails and in particular external links like
are evil if the MUA actually honors them (which many meanwhile seem to
do again; see all these newsletters). Due to broken MIME parsers a
bunch of MUAs seem to concatenate decrypted HTML mime parts which makes
it easy to plant such HTML snippets.

There are two ways to mitigate this attack

- Don't use HTML mails. Or if you really need to read them use a
proper MIME parser and disallow any access to external links.

- Use authenticated encryption.

The latter is actually easy for OpenPGP because we started to use
authenticated encryption (AE) since 2000 or 2001. Our AE is called MDC
(Modification detection code) and was back then introduced for a very
similar attack. Unfortunately some OpenPGP implementations were late to
introduce MDC and thus GPG could not fail hard on receiving a mail
without an MDC. However, an error is returned during decrypting and no
MDC is used:

gpg: encrypted with 256-bit ECDH key, ID 7F3B7ED4319BCCA8, created 2017-01-01
"Werner Koch "
There is more to life than increasing its speed.
-- Mahatma Gandhi
gpg: WARNING: message was not integrity protected

When giving a filename on the command line an output file is even not
created. This can't be done in pipe mode because gpg allows to process
huge amounts of data. MUAs are advised to consider the DECRYPTION_FAILED
status code and not to show the data or at least use a proper way to
display the possible corrupted mail without creating an oracle and to
inform the user that the mail is fishy.

For S/MIME authenticated encryption is not used or implemented in
practice and thus there is no short term way to fix this in S/MIME
except for not using HTML mails.

The upshot of this is that OpenPGP messages are way better protected
against such kind of attacks than S/MIME messages. Unless, well, the
MUAs are correctly implemented and check error codes!



Some cryptographers turn up their nose at the OpenPGP MDC which is an
ad-hoc AE mode from a time before AE received much research. However,
it does it job and protects reliable against this and other attacks.
The next OpenPGP revision will bring a real AE mode (EAX or OCB
depending on key preferences) which has other benefits (early detection
of corrupted messages, speed) but it will takes years before it will be
widely deployed and can can actually be used to create messages.

# Please read: Daniel Ellsberg - The Doomsday Machine #
Die Gedanken sind frei. Ausnahmen regelt ein Bundesgesetz.

Alarmist articles

Subject: Re: [Enigmail] FYI disable enigmail now
Date: Mon, 14 May 2018 03:14:12 -0400
From: Robert J. Hansen
Reply-To: Enigmail user discussion list

We saw a preview of that paper. It's under embargo so it would be
inappropriate for us to comment on it until it's released. It was also
inappropriate for the EFF to comment on it. You can expect us to have
an official statement on it once the paper is published.

I will say this is a tempest in a teapot. Patrick, Werner, and I have
all seen it. We are not in the least bit worried. We wish the EFF had
reached out to us before running with an alarmist article.

tl;dr: as always, please use the latest Enigmail version, and do so with

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

More in Tux Machines

Red Hat Woes and Fedora 29 Plans

  • Shares of open-source giant Red Hat pounded on weaker outlook
  • Fedora 29 Aims To Offer Up Modules For Everyone
    The latest Fedora 29 feature proposal is about offering "modules for everyone" across all Fedora editions. The "modules for everyone" proposal would make it where all Fedora installations have modular repositories enabled by default. Up to now the modular functionality was just enabled by default in Fedora Server 28. The modular functionality allows Fedora users to choose alternate versions of popular software, such as different versions of Node.js and other server software components where you might want to stick to a particular version.

GNU Make, FSFE Newsletter, and FSF's BLAG Removal

  • Linux Fu: The Great Power of Make
    Over the years, Linux (well, the operating system that is commonly known as Linux which is the Linux kernel and the GNU tools) has become much more complicated than its Unix roots. That’s inevitable, of course. However, it means old-timers get to slowly grow into new features while new people have to learn all in one gulp. A good example of this is how software is typically built on a Linux system. Fundamentally, most projects use make — a program that tries to be smart about running compiles. This was especially important when your 100 MHz CPU connected to a very slow disk drive would take a day to build a significant piece of software. On the face of it, make is pretty simple. But today, looking at a typical makefile will give you a headache, and many projects use an abstraction over make that further obscures things.
  • FSFE Newsletter June 2018
  • About BLAG's removal from our list of endorsed distributions
    We recently updated our list of free GNU/Linux distributions to add a "Historical" section. BLAG Linux and GNU, based on Fedora, joined the list many years ago. But the maintainers no longer believe they can keep things running at this time. As such, they requested that they be removed from our list. The list helps users to find operating systems that come with only free software and documentation, and that do not promote any nonfree software. Being added to the list means that a distribution has gone through a rigorous screening process, and is dedicated to diligently fixing any freedom issues that may arise.

Servers: Kubernetes, Oracle's Cloudwashing and Embrace of ARM

  • Bloomberg Eschews Vendors For Direct Kubernetes Involvement
    Rather than use a managed Kubernetes service or employ an outsourced provider, Bloomberg has chosen to invest in deep Kubernetes expertise and keep the skills in-house. Like many enterprise organizations, Bloomberg originally went looking for an off-the-shelf approach before settling on the decision to get involved more deeply with the open source project directly. "We started looking at Kubernetes a little over two years ago," said Steven Bower, Data and Infrastructure Lead at Bloomberg. ... "It's a great execution environment for data science," says Bower. "The real Aha! moment for us was when we realized that not only does it have all these great base primitives like pods and replica sets, but you can also define your own primitives and custom controllers that use them."
  • Oracle is changing how it reports cloud revenues, what's it hiding? [iophk: "probably Microsoft doing this too" (cloudwashing)]

    In short: Oracle no longer reports specific revenue for cloud PaaS, IaaS and SaaS, instead bundling them all into one reporting line which it calls 'cloud services and licence support'. This line pulled in 60% of total revenue for the quarter at $6.8 billion, up 8% year-on-year, for what it's worth.

  • Announcing the general availability of Oracle Linux 7 for ARM
    Oracle is pleased to announce the general availability of Oracle Linux 7 for the ARM architecture.
  • Oracle Linux 7 Now Ready For ARM Servers
    While Red Hat officially launched RHEL7 for ARM servers last November, on Friday Oracle finally announced the general availability of their RHEL7-derived Oracle Linux 7 for ARM. Oracle Linux 7 Update 5 is available for ARM 64-bit (ARMv8 / AArch64), including with their new Unbreakable Enterprise Kernel Release 5 based on Linux 4.14.

Graphics: XWayland, Ozone-GBM, Freedreno, X.Org, RadeonSI

  • The Latest Batch Of XWayland / EGLStream Improvements Merged
    While the initial EGLStreams-based support for using the NVIDIA proprietary driver with XWayland was merged for the recent X.Org Server 1.20 release, the next xorg-server release will feature more improvements.
  • Making Use Of Chrome's Ozone-GBM Intel Graphics Support On The Linux Desktop
    Intel open-source developer Joone Hur has provided a guide about using the Chrome OS graphics stack on Intel-based Linux desktop systems. In particular, using the Chrome OS graphics stack on the Linux desktop is primarily about using the Ozone-GBM back-end to Ozone that allows for direct interaction with Intel DRM/KMS support and evdev for input.
  • Freedreno Reaches OpenGL ES 3.1 Support, Not Far From OpenGL 3.3
    The Freedreno Gallium3D driver now supports all extensions required by OpenGL ES 3.1 and is also quite close to supporting desktop OpenGL 3.3.
  • X.Org Is Looking For A North American Host For XDC2019
    If software development isn't your forte but are looking to help out a leading open-source project while logistics and hospitality are where you excel, the X.Org Foundation is soliciting bids for the XDC2019 conference. The X.Org Foundation is looking for proposals where in North America that the annual X.Org Developers' Conference should be hosted in 2019. This year it's being hosted in Spain and with the usual rotation it means that in 2019 they will jump back over the pond.
  • RadeonSI Compatibility Profile Is Close To OpenGL 4.4 Support
    It was just a few days ago that the OpenGL compatibility profile support in Mesa reached OpenGL 3.3 compliance for RadeonSI while now thanks to the latest batch of patches from one of the Valve Linux developers, it's soon going to hit OpenGL 4.4. Legendary open-source graphics driver contributor Timothy Arceri at Valve has posted 11 more patches for advancing RadeonSI's OpenGL compatibility profile support, the alternative context to the OpenGL core profile that allows mixing in deprecated OpenGL functionality. The GL compatibility profile mode is generally used by long-standing workstation software and also a small subset of Linux games.