7 ms·

Facebooks crawls every page recorded by its tracking pixel

• Angostura 9y ago
  Does it take notice of robots.txt?
• Artemix 9y ago
  Isn't it obvious? For which reason, if not tracking and information gathering, would such a feature even exist? Best solution is still to block Facebook's infrastructures, as always.
  • xstartup 9y ago
    I disagree, it's not at all obvious. Pixels are used for conversion tracking (cookie pixels/cookieless pixels). Crawl isn't necessary for a pixel to function.
    • lclarkmichalek 9y ago
      If you're trying to transmit trusted information in clientside js, then one common pattern is to have a user's browser to fire the data initially, then crawl to obtain a trusted copy. The last company I worked for did this, but skipped the second step, which led to all kinds of XSS attacks.
• dotdi 9y ago
  <rant> Shocking! Abuse of power and shady tracking techniques by Facebook? Unheard of! </rant> Seriously, this cannot be surprising after learning that the Messenger app listens to everything you do, all the time. That's just off the top of my head. They are doing this and much more.
  • rocqua 9y ago
    I've heard a lot of anecdotal reports of the messenger app listening to what you do. So much so that I've uninstalled the app. However, I've never seen a non-anecdotal source or even a source that gathers all anecdotes and gives a decent meta-analysis. Would you happen to have one?
    • Spooky23 9y ago
      The reply all podcast did a decent discussion of the topic. The messenger app probably doesn’t listen to you, but it’s abusive in other ways and shouldn’t be uninstalled. The main creepy feature of Facebook apps is that they continuously track your location. That’s a source of much of the creepy targeting that people notice. Also, Facebook’s weasel-worded response to the issue implies that they do not use pervasive audio targeting, but buy data from people who do. The Wired article that claimed that using audio was impractical is nonsense.
  • rock_hard 9y ago
    Please get your facts straight before posting here. https://www.wired.com/story/facebooks-listening-smartphone-microphone https://www.wired.com/story/facebooks-listening-smartphone-m...
    • dotdi 9y ago
      I've read the article before, and it's not convincing. I'm not one for conspiracy theories, but the article lists some forms of how it might work and reasons how it would be unfeasible. There are other ways this could work, IMHO.
    • nukeop 9y ago
      What facts? This article is full of inaccurate speculation but there are no facts in it. For example: >To make it happen, Facebook would need to record everything your phone hears while it's on. This assumption treated as an axiom here is false, and it makes the rest of the article inaccurate as well.
  • threeseed 9y ago
• unicornporn 9y ago
  > So yesterday we figured out that facebooks Facebot crawler will crawl _every_ url that was recorded by their tracking pixel. Not surprising at all. Would be interesting to see a write up on this.
• K0nserv 9y ago
  > 1. they are crawling potentially sensitive information granted by links with tokens Don't put Facebook tracking on sensitive pages. Actually as a service to your users don't put it anywhere where it doesn't add value. > 2. they are triggering potentially harmful and/or confusing actions in your website by repeating links They only perform idempotent[0]* requests which should not have any negative effect if performed multiple times 0: http://restcookbook.com/HTTP%20Methods/idempotency/ http://restcookbook.com/HTTP%20Methods/idempotency/ * They probably only actually perform GET in reality
  • d33 9y ago
    GET is only idempotent in theory. Way too many people abuse GET when creating websites.
    • eesmith 9y ago
      As an example of the problem, see the "Issues and criticism" of the related topic "Link prefetching" in Wikipedia - https://en.wikipedia.org/wiki/Link_prefetching#Issues_and_criticisms https://en.wikipedia.org/wiki/Link_prefetching#Issues_and_cr... .
      • icebraining 9y ago
        Almost all of those problems only apply to in-browser prefetchers, which reuse the user's session and connection.
        • eesmith 9y ago
          Point taken. Thanks for the correction.
    • mosselman 9y ago
      I believe that is the point that @K0nserv is making. The 'abuse' part I mean.
    • VMG 9y ago
• slig 9y ago
  > they are triggering potentially harmful and/or confusing actions in your website by repeating links Not their fault. GET requests should not modify anything.
• gnud 9y ago
  I assume the crawler only does HEAD/GET-requests Your fault if your webpage changes anything based on a GET. Now, if the crawler doesn't honor robots.txt, then you can complain (loudly).
• receptor 9y ago
  This is borderline criminal. Practically CSRF attack.
  • smt88 9y ago
    This sounds a little extreme at first, but I actually totally agree. It's in murky waters when it comes to GDPR, for starters. Where do they draw the line? Why not run a keylogger through embedded like buttons and widgets? That sounds worse, but isn't all that much worse.
    • dspillett 9y ago
      > It's in murky waters when it comes to GDPR, for starters. I'm not sure about from facebook's side, but from the point of view of how GDPR applies to the side being crawled if they, as custodians of PII and other sensitive data, are handing it out to unauthenticated requests, they might be liable for punishment for lack of due diligence.
      • throwaway2016a 9y ago
        I agree with this. The website author is potentially liable for providing inadequate protections to the user's PII. I don't see anything that would implicate Facebook here. Although, there is an interesting side effect that applies to all crawlers in that website owners failing to protect their customer PII like this means that crawlers inadvertently gather and store personal data as a side effect. I can't help but wonder if there is some liability there and if there is if something like AI or pattern matching can help to scrub the info before it is stored.
        • dspillett 9y ago
          facebook might have an issue with having collected the data too, of course, but the source site definitely should be taking appropriate measures to avoid handing it out in the first place.
  • threeseed 9y ago
• zerostar07 9y ago
  is this the same crawler they use for external links ? if yes you can exclude them, their User-agent id is "facebookexternal"
• detaro 9y ago
  If security of sensitive information depends on tokens in the URL, don't just give those URLs to a third party, how would that ever be a reasonable thing to do? (especially since the third party apparently hasn't given you any guarantees on how they treat that, otherwise we wouldn't be having this conversation?) Do your users, your broken software and yourself a favor and don't put Facebook tracking crap everywhere.
  • radicalbyte 9y ago
    That's because our industry is full of hopelessly under qualified people who somehow manage to create software by randomly throwing together bits of code from stackoverflow / books and tweaking it until it "works".
    • tpllaha 9y ago
      That's true. But also trackers (especially big ones) deliberately try to make it as easy as possible to accidentally include them in your page. e.g: the if you use their cdn for fonts/style sheets, if you include a fb like button etc. A friend of mine covers this more extensively in this blog post which I found a very interesting read: https://remusao.github.io/posts/static-comments.html https://remusao.github.io/posts/static-comments.html So I think it's still concerning that once they're in, they start crawling. Although not very surprising I have to say... That's their business after all.
      • radicalbyte 9y ago
        Yeah, of course they'll try that. They're businesses, they make their money by tracking people. When I inherit a team of project these CDN links are the second thing to get removed / fixed (after their the inevitable unencrypted passwords / homerolled security and homerolled SQL).
    • tzahola 9y ago
      You mean "hopelessly", right?
• Quppa 9y ago
  I don't mind Facebook crawling pages as long as it respects robots.txt, but for the last few weeks we've been hammered by requests from Facebook-owned IP addresses (millions of hits daily, 50+ for the same URL at times). They don't even set the User-Agent header. There's a bug report regarding the missing header here: https://developers.facebook.com/bugs/1654459311255613/ https://developers.facebook.com/bugs/1654459311255613/ Unfortunately it seems impossible to get in touch with Facebook devs directly.
  • AznHisoka 9y ago
    what site do you own (if you can tell)?
    • Quppa 9y ago
      Not sure I can say. On a positive note, it's given us an opportunity to focus on performance improvements :)
  • ikeboy 9y ago
    Send a cease and desist to the CTO. Wait 30 days, then sue under the CFAA. LinkedIn did it
    • icebraining 9y ago
      No, LinkedIn was sued by the recipient of the letter.
• dspillett 9y ago
  > we figured out that facebooks Facebot crawler will crawl _every_ url that was recorded by their tracking pixel. I would be more surprised to find out that they didn't crawl everything they can, specifically pages that invite them in. > 1. they are crawling potentially sensitive information granted by links with tokens If the page contains sensitive information you absolutely should not have code that you do not control (any code loaded from third party hosts, not just facebook's bits). As a matter of security due diligence if you have third party hosted code linked into any such pages you should remove it with some urgency and carefully review the design decisions that lead to the situation. If you really must have the third party code in that area then you'll need to find a way of removing the need for the tokens being present. Furthermore, if the information is sensitive to a particular user then your session management should not permit a request from facebook (or any other entity that has not correctly followed your authentication procedure) to see the content anyway. > 2. they are triggering potentially harmful and/or confusing actions in your website by repeating links Possibly true, but again that suggests a design flaw in the page in question. I assume that they are not sending POST or PUT requests? GET and HEAD requests should at very least be idempotent (so repeated calls are not a problem) and ideally lack any lasting side effect (with the exception of logging). > 3. they are repeating requests in a broken way by not encoding url-parameters correctly That does sound like a flaw, but one that your code should be immune to being broken by. Inputs should always be verified and action not taken unless they are valid. This is standard practise for good security and stability. The Internet is a public place, the public includes both deliberately nasty people and damagingly stupid ones so your code needs to take proper measures to not allow malformed inputs to cause problems. You can't use "the page isn't normally linked from other sources so won't normally be found by a crawler" as a valid mitigation because the page could potentially be found by a malicious entity via URL fuzzing. > 4. I could not find a warning or note on their tracking-pixel documentation that pages tracked would be crawled later A warning would be nice, but again unless they explicitly say they won't do such things I would be surprised to find that they didn't not that they do.
• dna_polymerase 9y ago
  It is the fucking internet, if you put something on there you should expect someone to find it, be it a crawler or an attacker. > 1. they are crawling potentially sensitive information granted by links with tokens If tokens in GET params are your security concept: please leave the entire field. 2. they are triggering potentially harmful and/or confusing actions in your website by repeating links So you built something that can be triggered by a simple HTTP request and may have a harmful potential? Wow. 3. they are repeating requests in a broken way by not encoding url-parameters correctly You are kidding right? That's a problem to you? Either your Webserver drops these or your routes don't match, end of story. 4. I could not find a warning or note on their tracking-pixel documentation that pages tracked would be crawled later Not a problem, you put it on the web and it will be crawled. Did you ever use Chrome? They report every URL you type to the Google Crawler. Read that anywhere lately?
  • MattBearman 9y ago
    You're correct, but there's no need to be a dick about it
    • dcow 9y ago
      Can we make a minor exception for this case? Please? Let's trust the OP has a good sense of humor and can interpret critique apersonally.
  • kiloreux 9y ago
    While I certainly don't disagree with what you said. I think you need to look at his arguments as a way to protect user data. Not all users that use your "mediocre" technical solution are aware of how "mediocre" it is. And if tokens are sent with GET requests or whatever stupid thing.
  • rurounijones 9y ago
    Everything you said was technically correct yet the message will probably be lost due to the manner in which you decided to delivered it.
• agopaul 9y ago
  A while ago while looking at the apache logs I noticed that the AdWords remarketing pixel does the same, it was trying to crawl private URLs that are only accessible to 'admins' that are not linked publicly. I'm not sure if this is still valid as I blocked by using robots.txt. Also, the same crawler ignores the "User-agent: *" directive in the robots.txt file and you have to add specific rules for it: "User-agent: Adsbot-Google"
• gaius 9y ago
  Sorry, if you are using their tracking pixel then you deserve no sympathy for the consequences.
• boraturan 9y ago
  Highly likely that they are feeding all the data into a deep network for ad recommendation engine.
• throwaway2016a 9y ago
  This is a great example over outrage by someone who doesn't understand how the web works. Unfortunately this is a problem with lots of web developers but the author shouldn't take it personally but should try to learn from it. I can't understand if they don't though because some of the replies here are a little harsh. The summary of what most people are saying including some take aways: - If you put something on the Internet it is public. Period. It is up to you to keep prying eyes away from that page. You can do that with strong mechanisms (like passwords and firewalls) or weak (like robots.txt) but you need to do something. You can't expect a page on the Internet to be private. - Requests should never ever have anything sensitive in the query string. The query string is inherently logged. By your browser history, your web server, any tracking pixels like Facebook you put on the page, etc. If you absolutely must include a token in the URL (like with OAuth) make sure it is a temporary token and is immediately replaced with something more durable like a cookie or local storage, no unnecessary HTML is rendered, and the user is redirected to a new page that doesn't have it in the URL. - GET requests should be idempotent. They should avoid changing any data as much as possible and should not have side effects. This is specified directly in the HTTP spec. - If your page displayed sensitive data it should send the security tokens in a header field (like cookies or authentication). Users who hit the page without that header field should be responded to with a 404. - Your point #3 is an add one. It is a bug on the Facebook side, yes, but it doesn't support your primary argument. In fact, if they fixed that bug it would make the perceived issues in your primary argument worse. - Re #4 they don't need to warn you. See the first bullet. If it is on the internet it is public. Skype, Slack, Twitter, Google, all do the same thing.
• deleted 9y ago
  [deleted]
• eli 9y ago
  Does it crawl URLs blocked by robots.txt? I doubt it. If you don't want well-behaving crawler to crawl your site, there's your answer. But not all are well behaved...