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Re: [tor-talk] Evercookies / supercookies tracking & No Script whitelisting tracking sites



On 5/14/2012 1:56 PM, Mike Perry wrote:
The short answer is "Yes, we've looked into it. New Identity removes
evercookies."

The long answer is
https://www.torproject.org/projects/torbrowser/design/#new-identity and
https://www.torproject.org/projects/torbrowser/design/#identifier-linkability

The footnote is "Please help us test this shit in new releases. We just
had a race condition on the cache that allowed cache cookies to persist
for up to a minute after clicking New Identity (though they did go away
after that)."
https://trac.torproject.org/projects/tor/ticket/3846
https://trac.torproject.org/projects/tor/ticket/5715
How, pray tell, does clicking New Identity remove evercookies from 12 - 15 possible locations? The cache isn't the only place evercookies can be stored. How does it remove ANY cookies at all? Does that necessarily clear LSOs, clear different locations HTML5 data can be stored - like delete webappstore.sqlite - (even if you've not viewed HTML5 media, the cookies can still be place there), or all other known locations evercookies can be placed (so far)? I never heard or read that feature when using New Identity. Was I absent that day or were we waiting for just the right time for a big announcement?

Thus spake Joe Btfsplk (joebtfsplk@xxxxxxx):

The most recent versions of TBB&  No Script's default settings under
Advanced>External filters, is not to block hulu.com, .youtube.com.
The content type (I think) refers to shockwave|futuresplash.  How -
OR IF - No Script's blocking ability of "evercookies" w/ its
settings as it ships w/ TBB&  sites like * Hulu * that (at least in
recent past) were * confirmed * by several privacy investigation
projects to be using evercookie / Kissmetrics.com tracking cookie
technology.  These cookies are NOT blocked by disabling all cookies
/ all 3rd party cookies in Firefox.  Even if they were, TBB ships w/
allow all cookies enabled.

One of the many ways / places (up to 12 - 15) that the js loaded
evercookies can be placed is as an LSO / flash cookie.  There are
many other traditional&  non traditional places these cookies are
stored.  AFAICT from reading research, these cookies CAN transmit
data that could compromise Tor users' anonymity - as they certainly
can in Firefox.  They are also very difficult to del&  "stay"
deleted (thus, sometimes called Zombie cookies).  Deleting cookies
by "normal" means does NOT delete them.

Numerous research reports that I've read say one of the only ways to
block these is disable js for most sites (as in, using No Script),
but that supposedly makes users more susceptible to fingerprinting,
by only allowing certain sites to load js content.  Yet Hulu was one
of the worst offenders for using evercookies (I don't use Hulu,
BTW), but is whitelisted in NoScript.

Have Tor devs looked into THESE special types of cookies&  if they
potentially compromising anonymity or even increasing chances of
fingerprinting, due to information they transmit about every site
you visit?
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