{"id":268,"date":"2008-05-06T14:45:19","date_gmt":"2008-05-06T21:45:19","guid":{"rendered":"http:\/\/kennyw.com\/general\/268"},"modified":"2008-05-06T14:45:19","modified_gmt":"2008-05-06T21:45:19","slug":"wsdualhttp-and-faults","status":"publish","type":"post","link":"https:\/\/kennyw.com\/?p=268","title":{"rendered":"WsDualHttp and Faults"},"content":{"rendered":"<p>The other day a customer was sending unauthenticated messages to a service and the requests were timing out over WsDualHttp. When using WsHttpBinding or NetTcpBinding, the customer received an authentication MessageFault.&#160; Why was there no Fault returned over WsDualHttpBinding?<\/p>\n<p>The reason has to do with securing composite-duplex channels. WsDualHttp uses two HTTP connections to provide its duplex nature, and messages are correlated between these two connections based on WS-Addressing (ReplyTo\/MessageId).&#160; Because of this, the server behavior is entirely dependent on data received from the client. If this client is malicious, then he can cause the server to do a couple of things:<\/p>\n<ul>\n<li>Initiate arbitrary outbound connections<\/li>\n<li>Cause a &quot;bouncing DOS&quot; attack. For example, consider a server A that can send messages to server B that&#8217;s behind a firewall. Suppose that client C can send messages to A, but cannot send messages directly to server B (due to the firewall). Now suppose that the client sends a badly secured message to server A, with a ReplyTo equal to server B. If we send back a fault for unsecured messages over WsDualHttp, this would result in C being able to DOS server B due to bounce-assistance from server A.<\/li>\n<\/ul>\n<p>In addition, since these are two one-way channels, the HTTP response (202 Accepted) has already returned prior to the Security channel (or any higher-layer in the channel\/dispatcher stack) being called. So we cannot simply piggy-back the fault over the HTTP back channel.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The other day a customer was sending unauthenticated messages to a service and the requests were timing out over WsDualHttp. When using WsHttpBinding or NetTcpBinding, the customer received an authentication MessageFault.&#160; Why was there no Fault returned over WsDualHttpBinding? The reason has to do with securing composite-duplex channels. WsDualHttp uses two HTTP connections to provide [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-268","post","type-post","status-publish","format-standard","hentry","category-indigo"],"_links":{"self":[{"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/posts\/268","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/kennyw.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=268"}],"version-history":[{"count":0,"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/posts\/268\/revisions"}],"wp:attachment":[{"href":"https:\/\/kennyw.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=268"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kennyw.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=268"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kennyw.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=268"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}