
Secret Dots from Printer Outed NSA Leaker - banku_brougham
http://blog.erratasec.com/2017/06/how-intercept-outed-reality-winner.html?m=1
======
NamTaf
The arrest warrant says nothing about printer dots, actually. It says that
once they saw it was printed (per the Intercept showing them a copy to confirm
its legitimacy) they simply looked at who'd printed the original document.
Upon looking into the desk computers of those 6 people, she was the only
person who'd had email contact with the Intercept.

They didn't even need the yellow dots. She literally emailed the Intercept
from her work email and was one of a trivial number of people who'd printed it
in the first place.

~~~
retox
Does this strike anyone else as suspicious? To my mind she's either
incompetent or she intended to become a martyr.

~~~
kibwen
Third possibility: that she suspected she'd be caught regardless, and decided
that releasing this specific information publicly was more important than her
personal freedom.

Fourth possibility: that the NSA did use the forensic marks in question to
identify her, and fabricated a parallel construction in order to avoid
acknowledging the existence of said marks.

(But still, most likely this is Hanlon's Razor. What's there to be suspicious
about?)

~~~
pilsetnieks
> order to avoid acknowledging the existence of said marks

Not likely. It's been common knowledge for a long time.

~~~
Larrikin
The reporting on this everywhere besides tech sites has completely left this
part out. Its not common knowledge to a lot of people.

~~~
pilsetnieks
Do you mean tracking dots in general? They've been mentioned in mainstream
media, it's just that nobody cares.

[http://www.nytimes.com/2008/07/24/technology/personaltech/24...](http://www.nytimes.com/2008/07/24/technology/personaltech/24askk-001.html)

[http://www.washingtonpost.com/wp-
dyn/content/article/2005/10...](http://www.washingtonpost.com/wp-
dyn/content/article/2005/10/18/AR2005101801663.html)

~~~
pessimizer
That they were in two articles 10 years ago is not evidence either that it's
common knowledge or that no one cares. They have their own wikipedia article.

------
jacquesm
This is a really nice bit from TFA:

"FBI special agent Justin Garrick told a federal court that Winner – a cross-
fit fan who graduated high school in 2011 and was in the US Air Force
apparently as a linguist – confessed to reading and printing out the document,
despite having no permission to do so. "

So, she joined the company 3 months prior, and it was 'permission' rather than
enforced access rights that they relied on for new trainees not to color
outside of the lines.

It's not about 'permission', it is all about 'capabilities'.

~~~
netsharc
It's the same with the NSA's excuse.. "Yes we gather Americans'
communications, but there are rules against agents listening to that!".

Or Facebook apps, "Yes apps can see your name, dob, email and your friends
list, but they are not allowed to abuse this information"... Thanks, I feel
secure now.

~~~
wbl
People could break your door and rob but don't. Punishment and deterrence work
in real life.

~~~
jacquesm
Well, you did start with the assumption the door would be locked. If you left
it open that would be the rough equivalent of what happened here.

~~~
AnimalMuppet
I once went around and taped a note to about 50 doors in my neighborhood. As I
recall, two of them opened at my touch - they weren't securely latched. At
that point, it didn't matter if they were locked.

------
FatalLogic
According to the FBI arrest affidavit, only six people printed that document,
and she emailed The Intercept from her own work computer.

So she would have been identified even if she or The Intercept had the sense
to remove or alter the DocuColor dots.

"The U.S. Government Agency conducted an internal audit to determine who
accessed the intelligence reporting since its publication. The U.S. Government
Agency determined that six individuals printed this reporting. WINNER was one
of these six individuals. A further audit of the six individuals' desk
computers revealed that WINNER had e-mail contact with the News Outlet. The
audit did not reveal that any of the other individuals had e-mail contact with
the News Outlet"

~~~
kibwen
Not that that makes it any less concerning that The Intercept forgot to scrub
the dots, unless the email in question contained instructions along the lines
of "lol dont worry bout opsec i dont care if i get caught kthx <3 <3".

~~~
ckastner
From The Intercept's "how to pass on tips" page [1]:

> _We’ve taken steps to make sure that people can leak to us as safely as
> possible. Our newsroom is staffed by reporters who have extensive experience
> working with whistleblowers, as well as some of the world’s foremost
> internet security specialists. Our pioneering use of the SecureDrop platform
> enables you to communicate with our reporters and send documents to us
> anonymously._

I think it's _shocking_ that nobody at The Intercept was aware of the yellow
dots, or other metadata (eg printer-specific output artifacts) that might
facilitate the revelation of the anonymous source. This is so careless of them
that I'm led to believe that they don't have a formal scrubbing step at all.

Of course, I might be biased a bit here because I dislike Greenwald so much
for how he handled the Snowden leaks. The risks Snowden took and the
sacrifices he made are incomparable, but "it took Greenwald several more
months and help from experts before he could learn relatively basic tools like
PGP encryption."

[1] [https://theintercept.com/leak/](https://theintercept.com/leak/)

[2] [https://www.dailydot.com/layer8/edward-snowden-gpg-for-
journ...](https://www.dailydot.com/layer8/edward-snowden-gpg-for-journalists-
video-nsa-glenn-greenwald/)

Edit: I think it's shocking because assisting whistleblowers and protecting
their anonymity seems central to The Intercept (which I believe is
commendable), so they, of all people, should know better -- if not _best_.

~~~
dredmorbius
Despite my criticisms of other comments of yours, this is an extremely cogent
point. _The Intercept_ should, nay, _must_ have policies, procedures, and
checks in place to prevent foul-ups of this nature. And must also produce a
post-mortem on this incident.

Screw-ups happen. _Repeated_ screw-ups show a systemic failure.

------
gszathmari
I have submitted a PR to 'pdf-redact-tools' tonight. The new feature removes
the yellow printer dots by converting the document to black and white:
[https://github.com/firstlookmedia/pdf-redact-
tools/pull/23](https://github.com/firstlookmedia/pdf-redact-tools/pull/23)

~~~
qb45
Are you very damn sure that it works and doesn't just convert them into
#fefefe dots?

~~~
arfar
But #fefefe isn't black or white? I presume the commenter specifically didn't
say greyscale.

EDIT- checked the source:

It looks like imagemagick's 'threshold' [0] command is being used, so
everything is max/min/black/white:

[https://github.com/firstlookmedia/pdf-redact-
tools/pull/23/c...](https://github.com/firstlookmedia/pdf-redact-
tools/pull/23/commits/e5e110f4f52bae58a5538c8b99f272050e99f506#diff-3bdc5abf0a60ad14fab98eb6df02c7a6R88)

[0] [https://www.imagemagick.org/script/command-line-
options.php#...](https://www.imagemagick.org/script/command-line-
options.php#threshold)

------
e2e8
The arstechnica article[1] reports, based on the FBI document, that the NSA
determined who leaked the info by finding creases in the documents provided to
them for authentication by the Intercept demonstrating that they were leaked
by being printed out.

[1] [https://arstechnica.com/security/2017/06/leaked-nsa-
report-s...](https://arstechnica.com/security/2017/06/leaked-nsa-report-says-
russians-tried-to-hack-state-election-officials/)

~~~
RachelF
The Register (as usual) has great coverage of this:

[https://www.theregister.co.uk/2017/06/06/contractor_leaked_r...](https://www.theregister.co.uk/2017/06/06/contractor_leaked_russians_hacking_election_systems/)

It turns out REALITY WINNER isn't an NSA exploit – it's her real name

~~~
qubex
In reality winner lost against the NSA.

~~~
jacquesm
But first the NSA lost against her.

------
jagermo
I don't get it. These kind of dots are not news, they have been around for
ages, the EFF cracked the code in 2005
([https://en.wikipedia.org/wiki/Printer_steganography](https://en.wikipedia.org/wiki/Printer_steganography))

Why did no one at the intercept check for them? Its trivial and they have to
know about this kind of stuff?

~~~
LeifCarrotson
I don't want to sound like a tinfoil hat wearer, but there's a lot of trivial
data that a leaker could/should guard against. Multi-layer PDFs and their
metadata. Microsoft Office metadata. Photograph EXIF data. Tracking cookies.
File access logging. Print job logging. Printer microdot steganography.
Traffic and license plate cameras. Cell tower connections logs. Email headers.
Windows event logs.

Many of these can be circumvented through the use of tech like VPNs, Tor, or
GPG, and through careful behavior such as scrubbing metadata and the use of
burner phones/laptops, cash, and public internet connections. And we're not
even getting to the level of wireless carrier, home ISP, or NSA web activity
tracking, NSA Tor exploitation, or zero-day exploits. Furthermore, this
assumes that the documents themselves are not themselves subject to
punctuation, word replacement, typesetting, or other content steganography.
Should The Intercept be responsible for ensuring that its sources adhere to
safe leaking behaviors? They probably should, at some level.

But what if - as I'm reading here - The Intercept got an email from
reality.winner@nsa.gov, subject "NSA Report on Russia Spearphishing.pdf", body
"Hey, I was browsing some stuff out of curiosity in our SCIF and thought this
study might be useful to you. I printed it off and smuggled it out in my
purse, then scanned it and attached it to this email. Please publish it so the
American people can know what's really going on. Hope this helps! -- Reality".
There's not really any point to worrying about printer steganography,
protecting your IP address, or GPG at that point.

~~~
flavio81
Your assessment is totally correct. Steganography can be put everywhere.
Perhaps the Free Software Foundation can take advantage of these cases for
pushing for more use of open source, non-fingerprinted software.

OR for enforcing fingerprinting! (It can help with fighting against corrupt
governments)

------
russdill
Or more accurately, the Intercept either though ineptitude or malice burned
their source.

~~~
1024core
I would call it criminal ineptitude.

They (the Intercept) are playing in a dangerous game, and they should be extra
careful about such things. After all the drama about smashed hard drives,
Greenwald's BF being detained in London, etc. etc. you'd think they'd know
better.

I'm not in the security business, and even I knew about the dots (and circles
in the $20 bills). It's been on HN several times:
[http://goo.gl/h1kqbu](http://goo.gl/h1kqbu)

So, shame on you, Intercept. Your callous disregard for your sources is now
going to send one to prison for a looong time.

------
Simulacra
"Yes, this code the government forces into our printers is a violation of our
3rd Amendment rights"

FYI: The 3rd Amendment reads as follows:

"No Soldier shall, in time of peace be quartered in any house, without the
consent of the Owner, nor in time of war, but in a manner to be prescribed by
law."

I don't see the connection. Why does this violate our 3rd amendment rights?

~~~
orangecat
One could argue that the "spirit" of the 3rd Amendment is that the government
cannot compel you to use your own resources for their benefit on an ongoing
basis. It's a stretch, but possibly no more so than other interpretations of
the Constitution that courts have made.

~~~
Simulacra
Good point, but in this case I don't know if it's quite reaching the level of
compelling. Maybe co-opting? I imagine the government uses us in many, many
ways for their own gain that we may not know of. Perhaps a better connection
might be the 1st Amendments implied right to freedom of association.

------
rl3
> _To fix this yellow-dot problem, use a black-and-white printer, black-and-
> white scanner, or convert to black-and-white with an image editor._

I'm not convinced that would be sufficient, especially the latter option.

Also this is the NSA. If they're smart, they have backup fingerprinting that
isn't publicly known.

~~~
cnvogel
Yes, b/w converting is not sufficient. Once printed, the yellow dots are hard
to remove.

[http://imgur.com/a/kLovh](http://imgur.com/a/kLovh)

And even when you mask them out so that they are no longer visible in the "all
white" (paper) background, e.g. by messing with the white/black point of the
image there's still the possibility that they could be recovered with
correlation methods in grey areas where they aren't visible to the naked eye
or just by increasing the contrast.

~~~
thaumasiotes
Why would there be grey in a thresholded image? The entire point of the
transform is that it maps everything above a certain threshold to pure white
and everything else to pure black.

They didn't say "convert to greyscale".

~~~
cnvogel
> They didn't say "convert to greyscale".

Very good point. But even then, assume that one page of a leaked document
contains a large picture with areas around the thrshold value: With the agency
being able to recreate a perfect replica of the initially scanned paper
version, but without yellow dots, it might be possible to extract the (very
few) bits necessary to boil it down to a single printer serial number by
statistical methods.

~~~
davidsong
Hmm, okay, so we reduce to black and white, add some warp and noise and then
reduce the size so that the text is only just readable.

...and they focus on adding fonts of multiple sizes so it can't be shrunk
without losing information.

~~~
thaumasiotes
Reduce to black and white, and proofread for dots. If they're still there,
they will be easy to see, since you only have two colors. You can white out an
image that came out looking like a test pattern.

------
yborg
So this is the "extraordinary law enforcement effort" Rosenstein referred to.
Check printer logs, send FBI to leaker's house.

This will certainly make anybody thinking of leaking to the Intercept think
twice.

~~~
fapjacks
I'm not sure how to say this, but I've been in a position to see what the US
government considers some of its most valuable technical resources. More than
a decade ago, a very specific breach of security happened in a specific place,
operated by "a company". That organization sent in a team of people from D.C.
for five days that specifically were "extraordinarily good" at their jobs in
order to analyze the machines where this breach happened. All three of these
folks were stumped _for three days_ by deleted browser cookies on a Windows
machine, no kidding. I was originally one of a handful of suspects, but
hearing about their ineptitude was _so fucking infuriating_ that I wouldn't
keep quiet. Eventually, one of the people in power in that place (who was on
my side) convinced the "crack forensics team" to hear me out. So I met with
them and discussed the plan, and then I walked them through installing a
stupid FOSS utility for recovering deleted browser cache and cookies, and they
were able to extract a URL, account name, and timestamp from the cookies on
the machine which then let them pull up the right footage from the security
camera, and catch the criminal responsible. The person in charge of the whole
thing offered me a job (which I did not take). Ever since that day, whenever I
hear something like "extraordinary law enforcement effort" I think about those
_stupid_ contractors and how I could have somehow suffered legal problems
because of them. I absolutely _do not_ trust the US government's claims about
its own technical capabilities. I mean obviously not everyone working for the
government is an ID-10-T, but here is supposedly one of the best technical
teams this organization has to offer, and they can't even get this really
basic shit right. And not just "can't get it right" but consider the
ramifications of their being wrong! Amazing, and eye-opening, and frightening.

~~~
cafard
Quite. The US government employs contractors more or less on the Charlie Sheen
principle: it pays them to go away. There are some really sharp people
employed by contractors, and some others that are just billed as if they were.

------
Jonnax
With all the talk of scanning in black and white, photocopying, taking a photo
with a camera or retyping as means to get around the printer dots.

Why not use OCR?

~~~
DanBC
NSA uses punctuation and typos to steganographically insert source
information.

~~~
dredmorbius
Do you happen to have a source on that?

------
bsenftner
What did she reveal? That's what's important. Everything is focusing on how
she was caught. Nice distraction.

~~~
dredmorbius
Specifics of Russian activities, methods, and US intelligence awareness of
same, all of which are relevant.

The fact of the arrest strongly suggests the documents themselves are
accurate. If they don't reflect actual Russian _activity_ , they appear to
reflect US _intelligence_ of such activity.

If accurate, the documents corroborate a general pattern of activity of
election manipulation carried on from at _least_ June of 2016 through
November, which would be highly significant.

There is circumstantial evidence of vote tampering in at least North Carolina,
based on unexpected vote-tally convergence differences based on precinct size
(I'm not entirely sold on the story, though it seems to have some legs):
[http://www.votesleuth.org/north-
carolina-2016-overview/](http://www.votesleuth.org/north-
carolina-2016-overview/)

At a larger scale, this highlights weakensses in multiple elements of liberal
democratic institutions, mechanisms, communications, and media, as well as,
quite possibly, political bodies and individuals. Arguments which have been in
large part theoretical of risks of voting machines, email, and end-to-end
encryption are now looking to be substantial, actual, and potentially
existential threats.

That's some prime meat in my register.

------
rwmj
Can someone explain the reference to the Third Amendment at the end of the
article? Looking on Wikipedia, the 3rd Amendment is something to do with
quartering soldiers in private homes.

~~~
_jal
The theory is that by pressuring printer makers in to making all printed
documents trackable, the printer is an agent of the state quartered in your
home to spy on you.

A theory that isn't going to satisfy many people. It is interesting, though,
to ponder what would have happened at various points in history, had
$state_actor at the time had access to this tech.

------
reacweb
For privacy purpose, we should have free (open source) printers.

~~~
lb1lf
#1 feature should be allowing the insertion of microdot patterns of your
choice.

Whenever I hear of dubious 'features' like this, I dream of seeing them
backfire on one of their supporters.

Say, next time there's a leak, the microdots show the source to be a printer
in the White House.

If nothing else, it would make it trivial for the defense of a real leaker to
show that forging the pattern is a very real possibility.

~~~
SmellyGeekBoy
Are these not forge-able now with modified firmware? Seems like this should be
a very real possibility.

------
mrb
I remember a HN thread years ago on these yellow dots watermarks, where an
employee at a printer manufacturer said there was no indication this was ever
used by law enforcement to track who printed what because, for one, the team
who implemented the watermarking never documented or taught anyone how to
decode these watermarks.

Well, here we are today with this NSA story.

I think it's possible that US-based printer manufacturers implemented
watermarking _on special request_ from the NSA. That would also explain why
the printer manufacturer employees never needed to teach anyone how to decode
them. It wasn't their specs in the first place.

------
rdtsc
As someone else pointed out already there is no evidence the dots were used.
Only 6 people viewed the document and she was the one who printed it. Then
they found logs of her emailing it from her work computer.

------
bgribble
So there are definitely printer dots in the posted images, but how do we know
they are from a printer at NSA? They could be from a printer at The Intercept,
a public copy and print shop, or anywhere else, intentionally left in as a red
herring.

Of course, as others have posted, she doesn't appear to have tried hard to
cover her tracks at NSA so that doesn't seem too likely. But stating that she
accidentally left in the printer dots is assuming several facts not in
evidence.

~~~
NoGravitas
The printer dots include the serial number of the printer. So _we_ don't know
if they are definitely from a printer at the NSA, surely the NSA does.

------
danso
tl;dr: the dots may have exposed metadata of the printing, but from what we
know officially, NSA's internal access control system was all that was needed
to argue probable cause against Reality Winner.

So the dots don't look good in terms of The Intercept's opsec, but from what
we know from the Justice Department's affidavit [0] and the search warrant
[1], those dots were likely inconsequential as evidence compared to the audit
trail that Winner left when she accessed and printed the file. It's not
unreasonable to believe that the NSA and its contractors can track access
activity by user, post-Snowden; I mean, it's a feature built into states' DMV
systems, which is how cops get busted in the occasional scandal of
unauthorized lookup of citizen info [2].

The warrant and affidavit allude to such a system when describing the audit
that was done as soon as the NSA was made aware (because the Intercept reached
out to them) that the document was out in the wild. At that point, it doesn't
seem hard to query their own logs to find all users who accessed and/or
printed out the document. Unfortunately for Winner, it seems that very few (1
in 6) NSA employees printed out the document, and I'm sure it didn't help that
her background (former Air Force, fluent in several Middle Eastern languages)
would indicate that her job did not require her to have a physical copy of
this particular document.

The affidavit and warrant mention "physical" metadata that they say supports
their case, but it's all circumstantial

1\. The documents show evidence of creases/folding, which indicates that
someone had to secret it out physically (i.e. they printed it first) from the
NSA. But that folding/creasing could come from the reporters printing out
their own copies of the document.

2\. The affidavit says that of the 6 employees to have had printed out the
document, Winner was the only one to have email contact with The intercept.
But the warrant specifies that this email contact occurred using her private
GMail address in _March_ , and it was limited to 2 emails: her subscribing the
The Intercept podcast, and a confirmation email. i.e. she didn't use email
(that we know of) to talk to the Intercept.

There's no mention of the yellow dots, which, sure, we could argue that the
NSA is just keeping that bit of tradecraft secret. But keep in mind that the
NSA started their investigation last week, with the FBI interviewing Winner
just a few days ago (on a Saturday no less).

The other key point is that, according to the warrant, the Intercept
journalist sent along the leaked documents to a NSA source for confirmation
_using a smartphone_ , i.e. they texted smartphone photos of the documents. It
seems possible that that kind of ad hoc scanning would make the yellow dots
illegible, depending on how much care was taken to photograph the documents.

At any rate, it's kind of irrelevant. Assuming Winner used her own NSA
credentials to peruse the system, the access control logs were all that were
needed to out her as fast as the NSA and FBI were able to. However, it's worth
noting that if the NSA had been clueless until the Intercept's published
report, the actual published document apparently did reveal the yellow dots.
This means that if even if Winner were one of many NSA employees to print out
the documents, the yellow-dot timestamp would greatly help in narrowing the
list of suspects.

So, it's wrong to say the Intercept outed her, because we don't know what
would've happened in an alternative reality in which the NSA didn't start its
investigation until after seeing the published report. It is OK, probably, to
speculate that the Intercept was sloppy in handling the documents...but that's
not what led to Winner being outed so quickly.

[0] [https://www.justice.gov/opa/pr/federal-government-
contractor...](https://www.justice.gov/opa/pr/federal-government-contractor-
georgia-charged-removing-and-mailing-classified-materials-news)

[1] [http://blog.erratasec.com/2017/06/how-intercept-outed-
realit...](http://blog.erratasec.com/2017/06/how-intercept-outed-reality-
winner.html#.WTYT4hPyvUI)

[2] [https://apnews.com/699236946e3140659fff8a2362e16f43/ap-
acros...](https://apnews.com/699236946e3140659fff8a2362e16f43/ap-across-us-
police-officers-abuse-confidential-databases)

~~~
shabbyfinal
> There's no mention of the yellow dots, which, sure, we could argue that the
> NSA is just keeping that bit of tradecraft secret

Printers have been using microdots since the 90's; their use isn't secret. And
the NSA would use other forms of forensic fingerprinting. For example, there's
some kerning variation in that document, which could easily be another form of
steganography. There are numerous other textual/grammar variations they could
use to watermark a document.

~~~
zumu
> the NSA would use other forms of forensic fingerprinting

This is what I'm betting on. The 'creases' story may have some truth to it,
but I suspect its primary goal is to take over the narrative and distract from
the actual methods of identify the leak.

------
coldtea
Arresting the leaker is part of making this seem legit leaking?

------
basicplus2
Convert the white background to yellow

~~~
rasz
dont print, make a picture of the screen with old camera bought in a car sale
town away.

~~~
londons_explore
If I were the NSA, I'd have a modified graphics driver which overlays
pseudorandom very faint grey dots over the screen at all times. A 254 254 254
pixel hidden amongst all while pixels isn't visible, yet thousands of them
across a page will encode significant amounts of information, even in the face
of quite severe image compression and low quality.

The dots could be based on the computer, currently logged in user, and
timestamp.

Then later, if any screenshot or screen photo is leaked, you can decode the
dots to identify the source.

~~~
cthalupa
You think that they would even be picked up when you take a picture with a
camera? Between the external camera, and then compression, I don't think that
the 254 254 254 pixels are going to make it into the final image. They might
not even make it into the initial picture - screen backlighting consistency,
etc, is going to wreak havoc on that from the start, before we even get into
sensor noise, etc on the camera, any smudges on the lens, all before it even
gets saved a jpg

~~~
londons_explore
There's an amazing way of encoding data called "gold codes". By having enough
pixels like this, you can correlate the image with the expected pattern, and
successfully extract data even though no individual pixel is visible.

It's used in GPS transmissions to allow decoding signals considerably weaker
than the background noise. Because the receiver is aware what the signal
should look like, it can extract it despite all the noise by averaging across
all the samples.

It _does_ require perfect alignment though, which might be tricky considering
camera lens warping, etc.

------
qq66
Something smells fishy here. How did the Intercept maintain enough opsec to
stay in contact with Snowden (who would have dropped them like a hot potato if
they didn't seem competent) and then do this, with the same general staff in
place?

~~~
stevenwoo
From what I learned in Citizenfour, Snowden had to walk his contacts Laura
Poitras(Citizenfour maker)/The Intercept through all the steps needed before
he would communicate with them, and this latest person mistakenly trusted The
Intercept with the original paper document (instead of passing it through a
b/w filter, second step as recommended by the link).

~~~
netsharc
I believe you're wrong...

Before they even meet, Snowden asked Greenwald to set-up PGP/GPG so they can
securely talk/he can tell them what he has, Greenwald didn't manage to do
that/ignored this "anonymous person", Snowden found that Laura had a GPG key,
and knew Greenwald, so he asked her to help him set that up. This all happened
pre-Intercept, Greenwald was working for The Guardian at that time.

Despite his technical ineptitude, Greenwald was the only journalist Snowden
trusted with the info, he didn't go to NYTimes after the NYT delayed a story
about surveillance during the Bush admin until after Bush's reelection, he was
afraid the NYT would just go straight to the government before publication,
asking "So is this story legit?"...

