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ps. You could implement your own functionality to collect these reports. The Report-URI product (as opposed to header) is just a pre-written service to save yo

ps. You could implement your own functionality to collect these reports. The Report-URI product (as opposed to header) is just a pre-written service to save you rolling your own. You just need to build something to receive the HTTP POST statements and do something with the data. Or you look on GitHub and find someone's done that for you: https://github.com/seek-oss/csp-server https://github.com/seek-oss/csp-server (and more: https://github.com/search?utf8=%E2%9C%93&q=csp+report-to https://github.com/search?utf8=%E2%9C%93&q=csp+report-to). Specifics and examples of what `report-to` looks like here: https://wicg.github.io/reporting/#examples https://wicg.github.io/reporting/#examples There's also a nice blog about implementing the old `report-uri` header here: https://gdstechnology.blog.gov.uk/2015/02/12/experimenting-with-content-security-policy-on-gov-uk/ https://gdstechnology.blog.gov.uk/2015/02/12/experimenting-w...

johnlbevan2 9y ago
Here's a nice example of what the report packet looks like: { "@timestamp": "2016-07-07T12:01:03.044Z", "csp-report": { "document-uri": "http://example.com/signup.html", "referrer": "", "blocked-uri": "http://example.com/css/style.css", "violated-directive": "style-src cdn.example.com", "original-policy": "default-src \u0027none\u0027; style-src cdn.example.com; report-uri /_/csp-reports" } } Ref: https://github.com/seek-oss/csp-server/blob/master/example/csp-report-example.json https://github.com/seek-oss/csp-server/blob/master/example/c... I don't know what's in place (if anything) to prevent sending fake reports... i.e. presumably a hacker could read these headers from a site, then send HTTP POST messages reporting all kinds of errors from various IPs (e.g. if they have access to compromised machines), flooding your useful metrics with false data, thus hiding any useful information in there... Better than the current protocol, you'd have your site generate an ID for every legitimate request so that any reports could be tied back to that... but even then any hacker would just need to call your site once per false report to get that ID, so this only offers a small amount of additional protection (though in doing so increases the probability of the site being targeted by a flooding / DoS attack).
- dullgiulio 9y ago
  I haven't opened the ReportURI webpage, but I would assume their value added compared to DIY is exactly in spam-filtering and solving (or mitigating) all the security issues that report-uri (the header) inserts itself. Call me cynical, but I believe reporting causes more harm than good, by exposing new attack surface. Why not just deploy a crawler that detects CSP errors and reports them in a static report for the site owner?
  - johnlbevan2 9y ago
    Good point on ReportURI having better abilities to detect false reports. It's not mentioned (at least, not on the front page; I've not delved), but definitely their larger dataset will make it much simpler to blacklist IPs suspected of sending faked reports / spotting patterns to remove false data. I believe the benefit of having users' browsers report this over a crawler is for scenarios where pages attempt to display your content from another site (e.g. in an iframe behind an overlay for a click-jacking attack). You'd never know to monitor that URL / wouldn't know that the site was hosting your content from any of your metrics; but the users browsers would report it. In terms of "why report it if they know to block it anyway", I believe the idea is to improve security for others; i.e. we're no longer relying on users having the latest browser to be protected; so long as one user had a browser good enough to spot the issue, we can be made aware that there's a risk out there.
  - Ajedi32 9y ago
    CSP violations (such as XSS vulnerabilities) can manifest themselves on non-public pages, where they'd be difficult to detect with a crawler. In addition, the Web Reporting API covers more than just CSP. It can also report various types of certificate errors, such as those triggered by violations of the Expect-CT and Expect-Staple headers (such violations might occur if your users are under attack by a MITM).
    - dullgiulio 9y ago
      I imagine you realize that a user under MITM would have the report POST request tampered? It's false security. On the other hand, you are right that the crawler wouldn't catch everything.
3pt14159 9y ago
Sure, but you also should make sure it's on a different TLD, incase you've somehow misconfigured your HPKP cert pin.
- kuschku 9y ago
  HPKP is dead anyway, Chrome is dropping support for it in the next version anyway.
  - 3pt14159 9y ago
    I know and I completely disagree with that decision. HPKP has a place. Checking CA logs (via Expect-CT header) is bullshit because when the stakes are high enough some CA can get hacked or some low level sysadmin can verify domain control somehow and register a cert and some actor can MITM connections without anyone noticing for months. With HPKP the fucking page doesn't load. Period. You need to either root the server or use a PDA to stop HTTPS in the first place, but then the browser bar isn't green. If the costs of getting MITMed are high it is better to risk lockout than it is to risk silent data loss. At the very, very least I should be able to pin which CAs I trust so the threat vector doesn't include every CA in the world. The Expect-CT header is good enough for most people, but HPKP should be supported if needed.
    - dantiberian 9y ago
      > At the very, very least I should be able to pin which CAs I trust so the threat vector doesn't include every CA in the world. You can do this with CAA records today, to restrict which CAs can issue certificates for your domain.
      - lol768 9y ago
        This always seemed backwards to me. If the worry is that certs are being misissued, why on earth are we assuming that such CAs are following the rulebook? No, the browser should check the CAA record and refuse to trust certs issued by the wrong CA.
deadmetheny 9y ago
You can also implement Dropbox with a local FTP server, curlftpfs, and SVN.

johnlbevan2 9y ago

Here's a nice example of what the report packet looks like: { "@timestamp": "2016-07-07T12:01:03.044Z", "csp-report": { "document-uri": "http://example.com/signup.html", "referrer": "", "blocked-uri": "http://example.com/css/style.css", "violated-directive": "style-src cdn.example.com", "original-policy": "default-src \u0027none\u0027; style-src cdn.example.com; report-uri /_/csp-reports" } } Ref: https://github.com/seek-oss/csp-server/blob/master/example/csp-report-example.json https://github.com/seek-oss/csp-server/blob/master/example/c... I don't know what's in place (if anything) to prevent sending fake reports... i.e. presumably a hacker could read these headers from a site, then send HTTP POST messages reporting all kinds of errors from various IPs (e.g. if they have access to compromised machines), flooding your useful metrics with false data, thus hiding any useful information in there... Better than the current protocol, you'd have your site generate an ID for every legitimate request so that any reports could be tied back to that... but even then any hacker would just need to call your site once per false report to get that ID, so this only offers a small amount of additional protection (though in doing so increases the probability of the site being targeted by a flooding / DoS attack).

dullgiulio 9y ago
I haven't opened the ReportURI webpage, but I would assume their value added compared to DIY is exactly in spam-filtering and solving (or mitigating) all the security issues that report-uri (the header) inserts itself. Call me cynical, but I believe reporting causes more harm than good, by exposing new attack surface. Why not just deploy a crawler that detects CSP errors and reports them in a static report for the site owner?
- johnlbevan2 9y ago
  Good point on ReportURI having better abilities to detect false reports. It's not mentioned (at least, not on the front page; I've not delved), but definitely their larger dataset will make it much simpler to blacklist IPs suspected of sending faked reports / spotting patterns to remove false data. I believe the benefit of having users' browsers report this over a crawler is for scenarios where pages attempt to display your content from another site (e.g. in an iframe behind an overlay for a click-jacking attack). You'd never know to monitor that URL / wouldn't know that the site was hosting your content from any of your metrics; but the users browsers would report it. In terms of "why report it if they know to block it anyway", I believe the idea is to improve security for others; i.e. we're no longer relying on users having the latest browser to be protected; so long as one user had a browser good enough to spot the issue, we can be made aware that there's a risk out there.
- Ajedi32 9y ago
  CSP violations (such as XSS vulnerabilities) can manifest themselves on non-public pages, where they'd be difficult to detect with a crawler. In addition, the Web Reporting API covers more than just CSP. It can also report various types of certificate errors, such as those triggered by violations of the Expect-CT and Expect-Staple headers (such violations might occur if your users are under attack by a MITM).
  - dullgiulio 9y ago
    I imagine you realize that a user under MITM would have the report POST request tampered? It's false security. On the other hand, you are right that the crawler wouldn't catch everything.

3pt14159 9y ago

Sure, but you also should make sure it's on a different TLD, incase you've somehow misconfigured your HPKP cert pin.

kuschku 9y ago
HPKP is dead anyway, Chrome is dropping support for it in the next version anyway.
- 3pt14159 9y ago
  I know and I completely disagree with that decision. HPKP has a place. Checking CA logs (via Expect-CT header) is bullshit because when the stakes are high enough some CA can get hacked or some low level sysadmin can verify domain control somehow and register a cert and some actor can MITM connections without anyone noticing for months. With HPKP the fucking page doesn't load. Period. You need to either root the server or use a PDA to stop HTTPS in the first place, but then the browser bar isn't green. If the costs of getting MITMed are high it is better to risk lockout than it is to risk silent data loss. At the very, very least I should be able to pin which CAs I trust so the threat vector doesn't include every CA in the world. The Expect-CT header is good enough for most people, but HPKP should be supported if needed.
  - dantiberian 9y ago
    > At the very, very least I should be able to pin which CAs I trust so the threat vector doesn't include every CA in the world. You can do this with CAA records today, to restrict which CAs can issue certificates for your domain.
    - lol768 9y ago
      This always seemed backwards to me. If the worry is that certs are being misissued, why on earth are we assuming that such CAs are following the rulebook? No, the browser should check the CAA record and refuse to trust certs issued by the wrong CA.

deadmetheny 9y ago

You can also implement Dropbox with a local FTP server, curlftpfs, and SVN.