Mailing List Archive

ctf-like WKD challenge (was: WKD proper behavior on fetch error)
On 2021-01-20 at 08:08 +0100, Stefan Claas via Gnupg-users wrote:
> On Wed, Jan 20, 2021 at 12:41 AM Ángel <angel@pgp.16bits.net> wrote:
>
> > A list of all (well, most) openpgpkey subdomains can be easily
> > created.
>
> Yes and I believe that what Neal and you (in your new posting) have
> explained makes it only worthwhile for Mallory to start his work,
> because he has such an openpgpkey list created.

No, no, no. The idea of my previous mail, was *precisely* that there is
no point for Mallory to do that.

Counting wkd servers can be interesting for statistics, measuring
adoption, etc. but that would be of no use for an attacker.


Ok, let's frame it a bit different. I will give a game for you.

Last night, I prepared the domain wkdtest.pgp.16bits.net It is a valid
wkd server. I have just created and uploaded there a new pgp key, and
you have to obtain it:


«We have intercepted the following communication sent to an spy using
an undisclosed openpgp implementation. Based on the detected network
traffic, we are sure the key itself was downloaded using wkd, and the
domain of the userid to be ‘wkdtest.pgp.16bits.net’

Your mission, should you choose to accept it, is to find out the name
of the spy to which this communication was addressed:


-----BEGIN PGP MESSAGE-----
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=6hHu
-----END PGP MESSAGE-----»


Can you figure this out?




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Re: ctf-like WKD challenge (was: WKD proper behavior on fetch error) [ In reply to ]
On Thu, Jan 21, 2021 at 12:25 AM Ángel <angel@pgp.16bits.net> wrote:

> Last night, I prepared the domain wkdtest.pgp.16bits.net It is a valid
> wkd server. I have just created and uploaded there a new pgp key, and
> you have to obtain it:
>
>
> «We have intercepted the following communication sent to an spy using
> an undisclosed openpgp implementation. Based on the detected network
> traffic, we are sure the key itself was downloaded using wkd, and the
> domain of the userid to be ‘wkdtest.pgp.16bits.net’
>
> Your mission, should you choose to accept it, is to find out the name
> of the spy to which this communication was addressed:
>
>
> -----BEGIN PGP MESSAGE-----

Well, I am not in the spy business, but according to the meta data
of the message it is addressed to key owner 0xCD2687BFBB7D2624,
if I see it right.

Since you write that you have intercepted the comms, you are aware
about the following phrase: 'people get assasinated by meta data ...'

I guess this is true, because last year China, for example, executed
24 CIA agents.

The nice things about OpenPGP amored messages is also that
procmail and friends can be used at providers to filter -----BEGIN blah

So in the end, I would say when one intercepts the communications
and according how MTAs work the involved parties should have it
not to difficult to figure out to whom the message(s) is intended for.

My motto is :TCP/IP where C stands for me for *Control* and P
for Protokoll, e.g. protokoll or log everything. ;-)

Best regards
Stefan

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Re: ctf-like WKD challenge (was: WKD proper behavior on fetch error) [ In reply to ]
On Thu, Jan 21, 2021 at 8:02 AM Stefan Claas
<spam.trap.mailing.lists@gmail.com> wrote:

> The nice things about OpenPGP amored messages is also that
> procmail and friends can be used at providers to filter -----BEGIN blah

P.S. When Stale Schumacher ran the International PGP Homepage in the 90's
people could download PGP for Unix, VAX/VMS, Windows and the Mac
(there was no Linux IIRC available at that time) and there was a stealth
mode available, e.g. to hide the -----BEGIN blah in armored messages.

Regards
Stefan

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Re: ctf-like WKD challenge (was: WKD proper behavior on fetch error) [ In reply to ]
On 21/01/2021 07:10, Stefan Claas via Gnupg-users wrote:
> On Thu, Jan 21, 2021 at 8:02 AM Stefan Claas
> <spam.trap.mailing.lists@gmail.com> wrote:
>
>> The nice things about OpenPGP amored messages is also that
>> procmail and friends can be used at providers to filter -----BEGIN blah
>
> P.S. When Stale Schumacher ran the International PGP Homepage in the 90's
> people could download PGP for Unix, VAX/VMS, Windows and the Mac
> (there was no Linux IIRC available at that time) and there was a stealth
> mode available, e.g. to hide the -----BEGIN blah in armored messages.

... which was pure security theatre that made it look more obfuscated to
the untrained eye, but would never fool even the simplest automated tool.

It is important to remember what PGP is for, and what it is not for. It
is most definitely NOT for hiding metadata. No system based on email can
ever do that, so it is safer not to pretend otherwise.

If you need to hide your metadata from the state on pain of torture and
death, PGP is NOT the solution. Use Tor, use Signal. And even then
you're taking your chances because in many countries it is highly likely
that your endpoint is rooted, and no security software can protect you
from an pwned endpoint.

--
Andrew Gallagher
Re: ctf-like WKD challenge (was: WKD proper behavior on fetch error) [ In reply to ]
On Thu, Jan 21, 2021 at 12:25 PM Andrew Gallagher via Gnupg-users
<gnupg-users@gnupg.org> wrote:
>
> On 21/01/2021 07:10, Stefan Claas via Gnupg-users wrote:
> > On Thu, Jan 21, 2021 at 8:02 AM Stefan Claas
> > <spam.trap.mailing.lists@gmail.com> wrote:
> >
> >> The nice things about OpenPGP amored messages is also that
> >> procmail and friends can be used at providers to filter -----BEGIN blah
> >
> > P.S. When Stale Schumacher ran the International PGP Homepage in the 90's
> > people could download PGP for Unix, VAX/VMS, Windows and the Mac
> > (there was no Linux IIRC available at that time) and there was a stealth
> > mode available, e.g. to hide the -----BEGIN blah in armored messages.
>
> ... which was pure security theatre that made it look more obfuscated to
> the untrained eye, but would never fool even the simplest automated tool.
>
> It is important to remember what PGP is for, and what it is not for. It
> is most definitely NOT for hiding metadata. No system based on email can
> ever do that, so it is safer not to pretend otherwise.
>
> If you need to hide your metadata from the state on pain of torture and
> death, PGP is NOT the solution. Use Tor, use Signal. And even then
> you're taking your chances because in many countries it is highly likely
> that your endpoint is rooted, and no security software can protect you
> from an pwned endpoint.

Very well said, Andrew!

Things I usually post here are more or less for the little PGP user
whishing to improve his practices, when using OpenPGP software.

And regarding Signal, I would think twice about that, which would
be to much OT here on this ML, but I can tell people here when
I asked Moxie, Signal, Micah Lee a question they did not answer.
And when Elon Musk started to advertise Signal usage on Twitter
publicity he received a reply from me, which he then not answered.

As some of you may know I have sold my smartphone ...

Best regards
Stefan

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Re: ctf-like WKD challenge [ In reply to ]
On Thu, 21 Jan 2021 10:48, Andrew Gallagher said:

> It is important to remember what PGP is for, and what it is not
> for. It is most definitely NOT for hiding metadata. No system based on
> email can ever do that, so it is safer not to pretend otherwise.

Full Ack.

There are ways to hide meat data and they exists for a long time. Use
them or helpt to get them back to live. Tor is one option but it does
not really target mails because it is designed as a low-latency service.

> If you need to hide your metadata from the state on pain of torture
> and death, PGP is NOT the solution. Use Tor, use Signal. And even then

That is not corrct. OpenPGP can and is in the real world part of a
solution. But communication in a hostile environment requires training
and creative methods to convey the data. Signal for example is not a
solution because it is a centralized service, requires easy to subvert
OSes, backdoored updates can easiliy be pushed to users, easuy to block,
and so forth. It may be part of a solution.

> likely that your endpoint is rooted, and no security software can
> protect you from an pwned endpoint.

There are ways to mitigate this but again training is required.


Salam-Shalom,

Werner

--
Die Gedanken sind frei. Ausnahmen regelt ein Bundesgesetz.
Re: ctf-like WKD challenge [ In reply to ]
On 22/01/2021 10:32, Werner Koch wrote:
> On Thu, 21 Jan 2021 10:48, Andrew Gallagher said:
>
>> If you need to hide your metadata from the state on pain of torture
>> and death, PGP is NOT the solution. Use Tor, use Signal. And even then
>
> That is not corrct. OpenPGP can and is in the real world part of a
> solution. But communication in a hostile environment requires training
> and creative methods to convey the data.

Yes of course, sorry for the crude generalisation. Write in haste,
repent at leisure. :-(

--
Andrew Gallagher