diff --git a/lib/iframeProtection.js b/lib/iframeProtection.js
index ae90465..6457747 100644
--- a/lib/iframeProtection.js
+++ b/lib/iframeProtection.js
@@ -11,43 +11,52 @@
 	else {
 		scope = require.register("./iframeProtection", {});
 	}
-	const {getWrapped} = require("./modifiedAPIFunctions");
 	
 	scope.protect = function protect(window, wrappedWindow, singleCallback, allCallback){
 		
-		[window.HTMLIFrameElement, window.HTMLFrameElement].forEach(function(constructor){
-			var oldContentWindowGetter = constructor.prototype.__lookupGetter__("contentWindow");
-			Object.defineProperty(
-				getWrapped(constructor.prototype),
-				"contentWindow",
-				{
-					enumerable: true,
-					configurable: true,
-					get: exportFunction(function(){
-						var window = oldContentWindowGetter.call(this);
-						if (window){
-							singleCallback(window);
-						}
-						return window;
-					}, window)
-				}
+		["HTMLIFrameElement", "HTMLFrameElement"].forEach(function(constructorName){
+			const constructor = window[constructorName];
+			const wrappedConstructor = wrappedWindow[constructorName];
+			
+			const contentWindowDescriptor = Object.getOwnPropertyDescriptor(
+				constructor.prototype,
+				"contentWindow"
 			);
-			var oldContentDocumentGetter = constructor.prototype.__lookupGetter__("contentDocument");
-			Object.defineProperty(
-				getWrapped(constructor.prototype),
-				"contentDocument",
-				{
-					enumerable: true,
-					configurable: true,
-					get: exportFunction(function(){
-						var document = oldContentDocumentGetter.call(this);
-						if (document){
-							singleCallback(document.defaultView);
-						}
-						return document;
-					}, window)
+			const originalContentWindowGetter = contentWindowDescriptor.get;
+			const contentWindowTemp = {
+				get contentWindow(){
+					var window = originalContentWindowGetter.call(this);
+					if (window){
+						singleCallback(window);
+					}
+					return window;
 				}
+			};
+			contentWindowDescriptor.get = exportFunction(
+				Object.getOwnPropertyDescriptor(contentWindowTemp, "contentWindow").get,
+				window
 			);
+			Object.defineProperty(wrappedConstructor.prototype, "contentWindow", contentWindowDescriptor);
+			
+			const contentDocumentDescriptor = Object.getOwnPropertyDescriptor(
+				constructor.prototype,
+				"contentDocument"
+			);
+			const originalContentDocumentGetter = contentDocumentDescriptor.get;
+			const contentDocumentTemp = {
+				get contentDocument(){
+					var document = originalContentDocumentGetter.call(this);
+					if (document){
+						singleCallback(document.defaultView);
+					}
+					return document;
+				}
+			};
+			contentDocumentDescriptor.get = exportFunction(
+				Object.getOwnPropertyDescriptor(contentDocumentTemp, "contentDocument").get,
+				window
+			);
+			Object.defineProperty(wrappedConstructor.prototype, "contentDocument", contentDocumentDescriptor);
 		});
 		[
 			// useless as length could be obtained before the iframe is created and window.frames === window
diff --git a/releaseNotes.txt b/releaseNotes.txt
index 32e7a98..d561bd7 100644
--- a/releaseNotes.txt
+++ b/releaseNotes.txt
@@ -6,7 +6,7 @@ Version 0.5.11:
 		- 
 	
 	fixes:
-		- 
+		- improved protection of (i)frame properties
 	
 	known issues:
 		- if a data URL is blocked the page action button does not appear
diff --git a/test/detectionTest.js b/test/detectionTest.js
index 9a133ce..48a1df1 100644
--- a/test/detectionTest.js
+++ b/test/detectionTest.js
@@ -200,6 +200,10 @@ addTest("function name", function(log){
 			func: window.__lookupSetter__("name"),
 			expectedName: "set name"
 		},
+		{
+			func: HTMLIFrameElement.prototype.__lookupGetter__("contentDocument"),
+			expectedName: "get contentDocument"
+		},
 	].map(checkName).some(function(b){return b;});
 });
 addTest("property descriptor", function(log){