diff --git a/src/chrome/content/rules/Threema-Forum.de.xml b/src/chrome/content/rules/Threema-Forum.de.xml
new file mode 100644
index 000000000000..6ef168fa34e4
--- /dev/null
+++ b/src/chrome/content/rules/Threema-Forum.de.xml
@@ -0,0 +1,12 @@
+<!--
+
+-->
+<ruleset name="Threema-forum.de">
+    <target host="threema-forum.de" />
+    <target host="www.threema-forum.de" />
+
+    <securecookie host="^(www\.)?threema-forum\.de" name=".+" />
+
+    <rule from="^http:"
+            to="https:" />
+</ruleset>