The listener is opened on INADDR_ANY, so it will accept any network

connection, no matter if it is originating locally or from the outside
of the host. There is no check in place to discard non-local
connections. The only security against a malicious attack would be
provided by a local firewall, which is not guaranteed to be installed on
every workstation kicad is used on.

I tested this, and a host running eeschema accepts connections on TCP
port 4243 from other hosts on the internet.

A patch to remedy this potentially serious security hole is attached. It
creates the listener on localhost instead. A flag is provided to allow
the creation of sockets on 0.0.0.0 instead, if required. localhost is
the default.

common/eda_dde.cpp

@@ -35,12 +35,15 @@ void SetupServerFunction( void (*remotefct)(const char* remotecmd) )
 
 /* Function to initialize a server socket
  */
-WinEDA_Server* CreateServer( wxWindow* window, int service )
+WinEDA_Server* CreateServer( wxWindow* window, int service, bool local )
 {
     wxIPV4address addr;
 
     // Create a new server
     addr.Service( service );
+    // Listen on localhost only if requested
+    if( local )
+        addr.Hostname( HOSTNAME );
 
     server = new wxServer( addr );
 

include/eda_dde.h

@@ -30,7 +30,7 @@
 /* autres fonctions */
 /********************/
 
-WinEDA_Server * CreateServer( wxWindow * window, int port );
+WinEDA_Server * CreateServer( wxWindow * window, int port, bool local = true );
 bool SendCommand( int port, const char* cmdline );
 void SetupServerFunction( void (*remotefct) (const char* remotecmd) );