Mitigate Maliciousness -- jQuery Europe 2013
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Mitigate Maliciousness Mike West https://mikewest.org/ G+: https://mkw.st/+ Twitter: @mikewest
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jQuery has made it possible for developers to move more and more complex application logic down from the server to the client. This is a huge opportunity for JavaScript developers, and at the same time presents a tempting target for folks with malicious intent. It's more critical than ever to ensure that we're doing the right things with regard to security, and happily, modern browsers are here to help. Here, we'll talk about some of the new ways in which you can mitigate the effects of cross-site scripting and other attacks.
Transcript of Mitigate Maliciousness -- jQuery Europe 2013
Mitigate MaliciousnessMike West
https://mikewest.org/G+: https://mkw.st/+Twitter: @mikewest
<script> doAstoundinglyAwesomeThing();</script>
<script> sneakilyExfiltrateUserData();</script>
XSS is scary.
scheme://host:port
https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet
<style> p { color: {{USER_COLOR}}; }</style><p> Hello {{USER_NAME}}, view your <a href="{{USER_URL}}">Account</a>.</p><script> var id = {{USER_ID}};</script><!-- DEBUG: {{INFO}} -->
[][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]][([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]+!+[]]]]+([][[]]+[])[+[[+!+[]]]]+(![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[+!+[]]]]+([][[]]+[])[+[[+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]((![]+[])[+[[+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]+(!![]+[])[+[[+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[+!+[]]]+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+[+!+[]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[+!+[]]]+[[!+[]+!+[]+!+[]+!+[]+!+[]+!+[]]]])()
[][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]][([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]+!+[]]]]+([][[]]+[])[+[[+!+[]]]]+(![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[+!+[]]]]+([][[]]+[])[+[[+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]((![]+[])[+[[+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]+(!![]+[])[+[[+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[+!+[]]]+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+[+!+[]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[+!+[]]]+[[!+[]+!+[]+!+[]+!+[]+!+[]+!+[]]]])()
alert(1)
“I discount theprobability
of perfection.” -Alex Russell
Not “if”, but “when”.
Before all else, send data securely
$ curl -I http://mkw.st/HTTP/1.1 301 Moved PermanentlyServer: nginx/1.3.7Date: Sun, 11 Nov 2012 19:36:15 GMTContent-Type: text/htmlContent-Length: 184Connection: keep-aliveKeep-Alive: timeout=20Location: https://mkw.st/
Set-Cookie: ...; secure; HttpOnly
Strict-Transport-Security: max-age=2592000; includeSubDomains
Public-Key-Pins: max-age=2592000; pin-sha1="4n972H…60yw4uqe/baXc="; pin-sha1="IvGeLsbqzP…j2xVTdXgc="
http://tools.ietf.org/html/draft-ietf-websec-key-pinning
http://www.html5rocks.com/en/tutorials/security/transport-layer-security/
Limit the browser’s capabilities
“Every program and every privileged user of the system should operate using the least amount of privilege necessary to complete the job.”
Jerome H. Saltzer, "Protection and the control of information sharing in multics"
http://traumwerk.stanford.edu/philolog/2009/10/homers_odyssey_in_art_sirens_f.html
Content-Security-Policy: default-src 'none'; style-src https://mikewestdotorg.hasacdn.net; frame-src https://www.youtube.com http://www.slideshare.net; script-src https://mikewestdotorg.hasacdn.net https://ssl.google-analytics.com; img-src 'self' https://mikewestdotorg.hasacdn.net https://ssl.google-analytics.com data:; font-src https://mikewestdotorg.hasacdn.net
Content-Security-Policy: default-src ...; script-src ...; object-src ...; style-src ...; img-src ...; media-src ...; frame-src ...; font-src ...; connect-src ...; sandbox ...; report-uri https://example.com/reporter.cgi
<script> function handleClick() { ... }</script><button onclick="handleClick()">Click me!</button><a href="javascript:handleClick()">Click me!</a>
<!-- index.html --><script src="clickHandler.js"></script><button class="clickable">Click me!</button><a href="#" class="clickable">Click me!</a>
<!-- clickHandler.js -->function handleClick() { ...}
document.addEventListener('DOMContentLoader', function() { for (var e in document.querySelectorAll('.clickable')) e.addEventListener('click', clickHandler);});
Content-Security-Policy-Report-Only: default-src https:; report-uri https://example.com/csp-violations { "csp-report": { "document-uri": "http://example.org/page.html", "referrer": "http://evil.example.com/haxor.html", "blocked-uri": "http://evil.example.com/image.png", "violated-directive": "default-src 'self'", "original-policy": "...", "line-number": "10" }}
http://www.html5rocks.com/en/tutorials/security/content-security-policy/
Remember two things:HTTPS: http://goo.gl/Pw6wU
CSP: http://goo.gl/QcuaK
mkw.st/+ @mikewest
Even fewer privileges!
<iframe src="page.html" sandbox></iframe><!-- * Unique origin * No plugins. * No script. * No form submissions. * No top-level navigation. * No popups. * No autoplay. * No pointer lock. * No seamless iframes.-->
<iframe src="page.html" sandbox="allow-forms allow-pointer-lock allow-popups allow-same-origin allow-scripts allow-top-navigation"></iframe><!-- * No plugins. * No seamless iframes.-->
<!-- User-generated content? (in The Near Future™) --><iframe seamless srcdoc="<p>This is a comment!</p>" sandbox></iframe>
http://www.html5rocks.com/en/tutorials/security/sandboxed-iframes/
