Following up on our post about the wildly exaggerated claims made about the purported XKeyScore source code released in Germany this week by hacker Jacob Applebaum, here’s a very interesting post by cybersecurity expert Robert Graham with evidence that the code may have been at least partly faked: Errata Security: Validating XKeyScore Code.
The burning questions about the XKeyScore “source code” is whether it’s real, and whether it come from Snowden. The Grugq (@thegrugq) has some smart insight into this, and I have my own expertise with deep-packet-inspection code. I thought I’d write up our expert analysis to the questions.
TL;DR: we believe the code partly fake and that it came from the Snowden treasure trove.
A slightly longer summary is:
- The signatures are old (2011 to 2012), so it fits within the Snowden timeframe, and is unlikely to be a recent leak.
- The code is weird, as if they are snippets combined from training manuals rather than operational code. That would mean it is "fake".
- The story makes claims about the source that are verifiably false, leading us to believe that they may have falsified the origin of this source code.
- The code is so domain specific that it probably is, in some fashion, related to real XKeyScore code - if fake, it's not completely so.
Here’s a point that jumped out at me immediately upon looking at the code: all over the Internet, people are claiming that the code identifies linuxjournal.com as an “exremist forum” — but that’s simply false. As I tweeted two days ago:
By the way, folks? It's another falsehood that the NSA considers http://t.co/0o8VJWSyxq to be an “extremist forum.”
There's a comment in the code that says TAILS is “advocated by extremists on extremist forums.” It does NOT call linuxjournal “extremist.”
Every time one of these NSA stories comes out, it's rife with misrepresentations and distortions like this.
Graham’s post agrees with this evaluation:
Another misrepresentation in the story is that the source calls the Linux Journal an extremist forum. That’s not true.
A comment does say that TAILS is “a comsec mechanism advocated by extremists on extremist forums”. This is true, as the picture (from the Grugq) demonstrates on the right: it’s a picture from an ISIS/jihad forum advocating the use of TAILS. But nowhere does it claim that the Linux Journal is one of those extremists — that’s something willfully made up by the authors of the story.
That the story already misrepresents the meaning of this source code hints that it may already be misrepresenting the provenance.