And this time *with* the link... I hate it when I do that.

http://webpolicy.org/2013/12/09/metaphone-the-nsa-three-hop/

Robin

On 11 Dec 2013, at 17:23, Robin Wilton wrote:

> Thanks Nicholas - this is useful and relevant analysis.
> 
> In case you haven't already seen it, this piece about some new research (at 
> Stanford... sorry ;^)  ) gives a similarly worrying perspective on the role 
> of "hub" sites in expanding the scope of the "three hops" rule. Your Step 2 
> is, I think, a very similar mechanism, and has significant privacy impact.
> 
> Yrs.,
> Robin
> 
> Robin Wilton
> Technical Outreach Director - Identity and Privacy
> Internet Society
> 
> email: [email protected]
> Phone: +44 705 005 2931
> Twitter: @futureidentity
> 
> 
> 
> 
> On 11 Dec 2013, at 16:43, Nicholas Weaver wrote:
> 
>> 
>> Cookies and user tracking are wonderful things.  If you are a intelligence 
>> service, that is.
>> 
>> Its now clear that the NSA (and, remember, any other intelligence service 
>> that might see such traffic can do the same thing) uses cookies/advertising 
>> for both tracking (e.g. HAPPYFOOT: Advertisement libraries (esp on Android) 
>> which broadcast location + IMEI in the clear -> easy user tracking) and 
>> targeting (e.g. Know the victim's google PREFID cookie through other means, 
>> then use it to target exploitation: 
>> 
>> http://apps.washingtonpost.com/g/page/national/nsa-signal-surveillance-success-stories/647/#document/p3/a135602
>> 
>> http://www.washingtonpost.com/blogs/the-switch/wp/2013/12/10/nsa-uses-google-cookies-to-pinpoint-targets-for-hacking/
>> )
>> 
>> Everyone on this list should now consider themselves an in-scope target from 
>> at least one foreign intelligence service...
>> 
>> 
>> But the intelligence services can do even better if they want.  Here's how:
>> 
>> The NSA or foreign intelligence wiretap has a possible candidate for attack, 
>> but not probable.  That is, they THINK they may want to do an exploitation 
>> attack but aren't sure...
>> 
>> 
>> 1)  On the packet-injecting wiretap, it sees a possible candidate and it 
>> does a packet injection of a 302 redirect to a "User ID" script on the 
>> exploit server for something inconsequentially small.
>> 
>> 
>> 2)  The user-ID script creates a hidden iframe.
>> 
>> Within that iframe, it opens up a bunch of other iframes to various sites, 
>> e.g.www.youtube.com,www.linkedin.com, www.yahoo.com, slashdot.org, etc.  
>> Namely ANLY (and well, all) sites which
>> 
>> a)  Identifies the user in the response
>> 
>> b)  Uses a user-identifying cookie that can be sent in the clear.
>> 
>> This causes the possible victim's browser to visit all these sites, 
>> identifying the victim to any wiretap that can see it.
>> 
>> 
>> 3)  Back on the packet-injecting wiretap, it looks for request/response 
>> pairs to the targeted sites, using the request to extract the user ID 
>> cookies and the response to match the user identification by quick & dirty 
>> parsing of the HTML in the response.
>> 
>> Since the wiretap knows the user identifications it wants to exploit, it now 
>> knows the user ID cookies it wants to exploit as well.
>> 
>> 
>> 4)  Back on the user-ID script, after a ~10 second delay, it then creates a 
>> second set of iframes to the various sites for different URLs.  This causes 
>> the possible victim's browser to revisit all the sites.  These requests 
>> contain the user's ID cookies, which any wiretap has now been able to map to 
>> "is this the actual person I want to target"
>> 
>> 
>> 5)  The packet injecting wiretap, now that it knows the user ID cookies it 
>> might want to target, packet injects an exploit against any desired user ID 
>> cookie...
>> 
>> 
>> This enables the packet injection/exploitation system to leverage all known 
>> user-identifying sites in the clear to target their exploitation with high 
>> precision, even when the potential victim doesn't attempt to visit the user 
>> identifying sites in the clear.
>> 
>> 
>> 
>> The requirements for ANY intelligence service to do this to target YOU are:
>> 
>> a)  They must see ONE web request from you in the clear pass ONE of their 
>> wiretaps when they consider you "just might be a possible target"
>> 
>> b)  They must see ONE of the user-identifying web requests pass ONE of their 
>> wiretaps, and you must be logged into that site.
>> 
>> 
>> As you can imagine, the set of possible actors able to do this actually ends 
>> up being pretty darn big...
>> 
>> The IETF needs to work for HTTPS-only, NOW, out of simple self defense.
>> 
>> 
>> --
>> Nicholas Weaver                  it is a tale, told by an idiot,
>> [email protected]                full of sound and fury,
>> 510-666-2903                                 .signifying nothing
>> PGP: http://www1.icsi.berkeley.edu/~nweaver/data/nweaver_pub.asc
>> 
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> 

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