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Timing attack against HSTS to sniff browser history in Chrome and Firefox

zyan.scripts.mit.edu

41–50 of 99 posts

Re: Timing attack against HSTS to sniff browser history in Chrome and Firefox

#41

Earlier quoted context omitted.

This has mostly been fixed. See http://dbaron.org/mozilla/visited-privacy and https://blog.mozilla.org/security/2010/03/31/plugging-the-cs...

Yes. If you're using a browser version that's been updated past 2010-2011, this will no longer work.

Yes, and if you're running an older browser, then the webserver can provide arbitrary code that just reads the history directly. :)

Re: Timing attack against HSTS to sniff browser history in Chrome and Firefox

#42

This approach is rather interesting. But I'm wondering whether a similar attack could be made by placing links on a web page and using the CSS :visited selector to change the style of visited web pages. Couldn't you then check which links have that formatting and which don't via JS?

This used to be possible, but browsers put into place various mitigations: restricting which properties a :visited selector can affect, always computing both the visited and non-visited style to avoid timing attacks, etc. http://dbaron.org/mozilla/visited-privacy has a writeup describing the issues and the solutions that were adopted.

Re: Timing attack against HSTS to sniff browser history in Chrome and Firefox

#43

Wow. Our corporate proxy isn't going to like that many requests that quickly from one box. I wonder if they can add a landing page.

Yan has hit the HN homepage before, so hopefully it can weather this storm too.

I believe voltagex_ meant outgoing requests from his/her location.

Re: Timing attack against HSTS to sniff browser history in Chrome and Firefox

#44
post #6

I hit the page from Chrome 45.0.2454.101 and it literally did not get a single site that I regularly visit. It did make a hit on Reddit, I guess, but I have only visited the site two or three times, and you could probably say that about 2/3 of the population.

Same on Firefox 41.0.2. It got 1 or 2 correct hits; a lot of correct ones in "sites you probably haven't visited" but then again that's not the hard part?

Re: Timing attack against HSTS to sniff browser history in Chrome and Firefox

#46

One nice thing is that it is quite inaccurate, I've visited a large number of the sites it tells me I haven't.

It's accurate depending on what you're looking for. Saying you didn't visit a site means you either did, or did not, but saying you did visit a site means you 100% did for sure. In the case of a negative the results are meaningless, but in the case of a positive they are accurate. Similar to a bloom filter

I've just checked my history and the sites I thought I have not visited do not show (2/14). Maybe 85%?

Re: Timing attack against HSTS to sniff browser history in Chrome and Firefox

#47
post #8

How much of this is accurate, and how much of this is simply the top XXX sites that people visit?

I pulled the list of domains out of the Alexa Top 1M plus some domains that my friends run. But I'm not biasing results towards showing up as visited by popularity or anything like that.

I didn't set up analytics to figure out how accurate results are for the average person; having manually checked with a few people's browsers, I'd say the accuracy rate is ~75%.

Re: Timing attack against HSTS to sniff browser history in Chrome and Firefox

#48
post #46

Earlier quoted context omitted.

It's accurate depending on what you're looking for. Saying you didn't visit a site means you either did, or did not, but saying you did visit a site means you 100% did for sure. In the case of a negative the results are meaningless, but in the case of a positive they are accurate. Similar to a bloom filter

I've just checked my history and the sites I thought I have not visited do not show (2/14). Maybe 85%?

Yeah, I think the accuracy so far has been like 75-80% among my friends (once httpseverywhere is disabled). PS: you can check whether sites are in your HSTS cache in chrome at chrome://net-internals#hsts

Re: Timing attack against HSTS to sniff browser history in Chrome and Firefox

#49
post #28
post #2

Probably a good idea to edit the title to indicate that this is an example attack site as well, not my favorite thing in general to land on without warning. No js seems to mean no worries though.

The results never leave your browser, though, so there's not much to worry about.

The JS code sent to kentonv's browser might be safe, but you can't really meaningfully comment on hobs' situation, since you don't have a copy of the JS code that was sent to hobs' browser.

Re: Timing attack against HSTS to sniff browser history in Chrome and Firefox

#50
post #27

Earlier quoted context omitted.

CSP, HSTS, and HPKP were all known to be exploitable for "supercookie" purposes, but not history sniffing like this. So it's fair to call this a novel attack.

No. Leaks were known far beyond the "supercookie", but attacks were not as high quality as these.

Could you link some older sources discussing some of these leaks? I'm having trouble finding any. Not doubting you, since you're probably right; would just be interested in reading them.
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