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Google Security Technology

How To Pull Location Data From Encrypted Google Maps Sessions 28

Posted by Soulskill
from the step-one-create-1:1-model-of-the-earth dept.
Trailrunner7 writes "In the last couple of years, Google and some other Web giants have moved to make many of their services accessible over SSL, and in many cases, made HTTPS connections the default. That's designed to make eavesdropping on those connections more difficult, but as researchers have shown, it certainly doesn't make traffic analysis of those connections impossible. Vincent Berg of IOActive has written a tool that can monitor SSL connections and make some highly educated guesses about the contents of the requests going to Google Maps, specifically looking at what size the PNG files returned by Google Maps are. The tool then attempts to group those images in a specific location, based on the grid and tile system that Google uses to construct its maps."
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How To Pull Location Data From Encrypted Google Maps Sessions

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  • by Anonymous Coward
    This is an example of an algorithm to guess based on image sizes based on knowledge of the system that Google uses to send map information, there is nothing wrong with the underlying technology. Google could easily stymie this if they wanted to. Moderately interesting, but not really news-worthy.
    • by tibit (1762298) on Monday February 13, 2012 @06:33PM (#39026575)

      Well, it has to do with the underlying technology: SSL, as it's normally applied, provides you with an unencrypted side channel that leaks information that you'd like kept private. To counter it would require sending a more-or-less fixed bandwidth SSL stream, padded with pseudorandom noise. That is a fundamental deficiency of SSL and many other cryptosystems that apply to interactive uses over the web: to keep everything private, it needs a fixed (and wasteful) bandwidth allocation.

      • by gnasher719 (869701) on Monday February 13, 2012 @06:37PM (#39026617)
        It doesn't even have to be fixed size; if these maps were let's say between 1000 and 10,000 bytes, then round up to a multiple of 500 bytes, and only twenty different sizes get transmitted - very little information left.
        • by bennomatic (691188) on Monday February 13, 2012 @07:01PM (#39026823) Homepage
          Even with only 20 different sizes, if there is enough variation between neighboring tiles, the groupings could still provide enough information to narrow things down significantly.
      • by DarkOx (621550)

        I don't know that it needs to be fixed bandwidth. For things like speech were rates of pauses can yield information absolutely. I would expect most attacks like this one could be thwarted with noop commands padded with random number of enough random bytes to put them within a few standard deviation of the applications typical transaction size, sent at a random internal again within what would be an expected rate of human interactions for the protocol.

        That still will result in the transmission of lots of j

      • by Rei (128717)

        The US learned a frustrating lesson about this in the 1980s when they discovered that this was precisely how the Soviets were listening into our communications in our war games exercises.

        Of course, we had a number of fun ways to listen in on them that they either didn't know about or kept forgetting about. Like how, for example, the radio signals on early mobile phones didn't just propagate laterally (which they were very careful about), but also up. And can be heard from really far up, if you have a good

    • Re: (Score:3, Insightful)

      by Hatta (162192)

      Why is it possible to determine the sizes of the images over HTTPS? Are they seriously opening a new connection for each and every image on the satellite map? What's wrong with opening one tunnel and shoveling everything through there?

      • by Anonymous Coward

        You can guess by the size of the ip packets. As they are not fixed. The meta data for the tcp packets is basically 'in the clear' (size destination etc). Given that meta data you can 'infer' that it is a small subset. Then give other similar sized packets you can narrow it down to exactly what they are looking at. This does require you however to have a LARGE subset of the data already mapped out.

        Didnt read the article. But that is my guess of how they did it.

  • by Lally Singh (3427) on Monday February 13, 2012 @06:20PM (#39026437) Journal

    This is a known-cyphertext attack using the tile filesizes as identifiers. Build a database of map tiles' sizes and coordinates (x,y,z) from gmaps, then compare against the SSL response stream.

    It doesn't say if it's only effective for satellite view.

    • Satellite and Terrain tiles seem to follow similar patterns in file sizes. The 'normal' view is vast amounts of nothing. What you see in the browser is an overlay of the terrain/sat/normal PNG images plus the actual map view GIF. So you have two sets of data to analyze.

      It's a lot of data. I once cached (ripped off) enough map tiles to build a mobile GPS enabled application for a small geographic area and the number of tiles is absolutely huge when you consider all the zoom levels. Triple the number o
      • by unrtst (777550)

        The article says he tested with just 3 cities. As you noted, it's a lot of data. It's a hell of a lot more data if you consider the whole world. I'm VERY curious if this would work at all if your local cache of tiles had all of them?

        I suspect that the number of potential matches would increase significantly if the test were repeated with the whole db... so you have to have a starting point for this to work (maybe geoip and assume they're looking locally), and at that point, what's it really worth?

        Don't get

  • So perhaps I'm new to this game - but this is a pretty cool hack. Using the sizes of PNG files over an encrypted channel to locate someone is pretty nifty.

    For those who know more: is SSL encryption predictable (size-wise)? If I have the same size payload, will it always generate the same size encrypted result?
    • by chrylis (262281)

      SSL is a protocol for agreeing on a set of encryption parameters to use (which cipher, what keys, and so on) rather than a cipher itself. The two most common ciphers, (3)DES and AES (as well as all the other block ciphers I know of) produce a ciphertext that's the same size as the plaintext (plus padding if necessary to fill out the block size). An SSL connection, however, frequently gzips the content before running it through the cipher, so the size of the ciphertext depends on the compressibility of the

    • First, it's not a hack. Second, you can only *guess* at what region the client is looking, not where the client is.
  • by eyenot (102141) <eyenot@hotmail.com> on Monday February 13, 2012 @06:21PM (#39026449) Homepage

    Could anybody brainstorm as to how this could be made lucrative? I don't imagine it, somehow.

    1. You're on a public wifi, unsecured, and I'm sniffing your packets, and uh oh, I'm getting information about where you are located. Wait... you're right over there. I can see you. Okay, I'm smart.

    2. Okay, you're far away, and somehow I hacked your network connection, and all I see is you're using Google. Or maybe I hacked you over unsecure wifi from the public bench over here. Anyways, I can see what location you're looking *at*. So... I come up to you, and I say, "Karl... Karl, are you looking at Mogadishu, Karl? You know... we, uh, we're not allowed to look at Mogadishu, Karl. It's against whatevers. So... you're FIRED, Karl. Clean out your locker, Karl!"

    Is this all plausible? What is this useful for, anyway?

    "I caught you looking at the world's largest beaver dam in northern Canada. I'm going to tell the boss I caught you looking at beaver on your lunch break. Guess what? He's going to totally misunderstand. He's going to fire you. I'm going to get the partnership. I might be a douche, but, you're saaaaaaaaaaaaaaack---tuh."

    Or how about this:

    "Hrmmmm my opponent seems to be spending a great deal of time looking at the Himalayas. Hrrmmmmm yesssss I think I have something to use against him there. Hrmmmmm the public sentiment could be turned again.... no.... well the.... his wife would not appreesh... uh.... well.... the U.S. government has a strict policy regarding.... no.... well wtf. There's something wrong with this fuck for staring at Katchenjunga all god damn day long."

    • by vidnet (580068)

      Your boss could keep track of where you plan to go if you use the office network, and he can keep track of where you are if you have VPN enabled on your phone or tablet and use Google navigation software.

      "You're not looking up addresses of our competitors, are you Karl? You know, we don't tolerate disloyalty here at the company. And did you visit a.. gentleman's club after hours yesterday? We're a family company, Karl. We need all employees to represent our family values at all times, also outside work."

  • An interesting take on attacking an SSL stream, but like said above how useful is this really? As the first reply said, it does sounds like a known-plaintext attack in that you know to look for a certain number of bits, and when taken together with other certain numbers of bits you can deduce the area of the world being viewed. Seems mostly academic, unless you're law enforcement or some other such entity who is recording traffic from a known bad guy and trying to determine his next target... (which then
    • by Mithent (2515236)
      True. There are some fringe uses, but mostly you're just going to be intercepting someone planning how to get to their meeting tomorrow, or looking for the nearest Starbucks. You'd have to have a target in mind before it would be worthwhile spending the computational resources.
  • by bundling tiles randomly google could make this approach much harder - if they accept that sometimes its a little slower.

We warn the reader in advance that the proof presented here depends on a clever but highly unmotivated trick. -- Howard Anton, "Elementary Linear Algebra"

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