diff --git a/addon/etc/rmupdate-addon.cfg b/addon/etc/rmupdate-addon.cfg
index cde4aa0..f456c31 100644
--- a/addon/etc/rmupdate-addon.cfg
+++ b/addon/etc/rmupdate-addon.cfg
@@ -1,5 +1,5 @@
 {
-  CONFIG_URL /addons/rmupdate
+  CONFIG_URL /addons/rmupdate/index.cgi
   CONFIG_DESCRIPTION {
     de {<li>System-Update</li>}
     en {<li>System-update</li>}
diff --git a/addon/lib/querystring.tcl b/addon/lib/querystring.tcl
new file mode 100644
index 0000000..bd1f01f
--- /dev/null
+++ b/addon/lib/querystring.tcl
@@ -0,0 +1,9 @@
+catch {
+  set input $env(QUERY_STRING)
+  set pairs [split $input &]
+  foreach pair $pairs {
+    if {0 != [regexp "^(\[^=]*)=(.*)$" $pair dummy varname val]} {
+      set $varname $val
+    }
+  }
+}
diff --git a/addon/lib/session.tcl b/addon/lib/session.tcl
new file mode 100644
index 0000000..eb183a6
--- /dev/null
+++ b/addon/lib/session.tcl
@@ -0,0 +1,13 @@
+#!/bin/tclsh
+
+load tclrega.so
+
+proc check_session sid {
+    if {[regexp {@([0-9a-zA-Z]{10})@} $sid all sidnr]} {
+        set res [lindex [rega_script "Write(system.GetSessionVarStr('$sidnr'));"] 1]
+        if {$res != ""} {
+            return 1
+        }
+    }
+    return 0
+}
diff --git a/addon/www/index.cgi b/addon/www/index.cgi
new file mode 100644
index 0000000..92bdf32
--- /dev/null
+++ b/addon/www/index.cgi
@@ -0,0 +1,12 @@
+#!/bin/tclsh
+
+source /usr/local/addons/rmupdate/lib/querystring.tcl
+source /usr/local/addons/rmupdate/lib/session.tcl
+
+if {[info exists sid] && [check_session $sid]} {
+    set fp [open "/usr/local/addons/rmupdate/www/rmupdate.html" r]
+    puts -nonewline [read $fp]
+    close $fp
+} else {
+    puts {error: invalid session}
+}
diff --git a/addon/www/index.html b/addon/www/rmupdate.html
similarity index 100%
rename from addon/www/index.html
rename to addon/www/rmupdate.html