diff --git a/lib/client.js b/lib/client.js
index 1ce3fc4986..0ac95dffae 100644
--- a/lib/client.js
+++ b/lib/client.js
@@ -91,7 +91,9 @@ Client.prototype.connect = function(name){
 
 Client.prototype.disconnect = function(){
   for (var id in this.sockets) {
-    this.sockets[id].disconnect();
+    if (this.sockets.hasOwnProperty(id)) {
+      this.sockets[id].disconnect();
+    }
   }
   this.sockets = {};
   this.close();
@@ -104,7 +106,7 @@ Client.prototype.disconnect = function(){
  */
 
 Client.prototype.remove = function(socket){
-  if (this.sockets[socket.id]) {
+  if (this.sockets.hasOwnProperty(socket.id)) {
     var nsp = this.sockets[socket.id].nsp.name;
     delete this.sockets[socket.id];
     delete this.nsps[nsp];
@@ -204,7 +206,9 @@ Client.prototype.ondecoded = function(packet) {
 
 Client.prototype.onerror = function(err){
   for (var id in this.sockets) {
-    this.sockets[id].onerror(err);
+    if (this.sockets.hasOwnProperty(id)) {
+      this.sockets[id].onerror(err);
+    }
   }
   this.onclose('client error');
 };
@@ -224,7 +228,9 @@ Client.prototype.onclose = function(reason){
 
   // `nsps` and `sockets` are cleaned up seamlessly
   for (var id in this.sockets) {
-    this.sockets[id].onclose(reason);
+    if (this.sockets.hasOwnProperty(id)) {
+      this.sockets[id].onclose(reason);
+    }
   }
   this.sockets = {};
 
diff --git a/lib/index.js b/lib/index.js
index 1612c0cfa3..4300b99328 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -348,7 +348,9 @@ Server.prototype.of = function(name, fn){
 
 Server.prototype.close = function(){
   for (var id in this.nsps['/'].sockets) {
-    this.nsps['/'].sockets[id].onclose();
+    if (this.nsps['/'].sockets.hasOwnProperty(id)) {
+      this.nsps['/'].sockets[id].onclose();
+    }
   }
 
   this.engine.close();
diff --git a/lib/namespace.js b/lib/namespace.js
index 1a5b7efcfd..8bf460a3e2 100644
--- a/lib/namespace.js
+++ b/lib/namespace.js
@@ -187,7 +187,7 @@ Namespace.prototype.add = function(client, fn){
  */
 
 Namespace.prototype.remove = function(socket){
-  if (this.sockets[socket.id]) {
+  if (this.sockets.hasOwnProperty(socket.id)) {
     delete this.sockets[socket.id];
   } else {
     debug('ignoring remove for %s', socket.id);
diff --git a/lib/socket.js b/lib/socket.js
index 1e50a0232b..d792038a45 100644
--- a/lib/socket.js
+++ b/lib/socket.js
@@ -59,7 +59,6 @@ function Socket(nsp, client){
   this.nsp = nsp;
   this.server = nsp.server;
   this.adapter = this.nsp.adapter;
-  this.id = client.id;
   this.id = nsp.name + '#' + client.id;
   this.client = client;
   this.conn = client.conn;
@@ -223,7 +222,7 @@ Socket.prototype.packet = function(packet, opts){
 Socket.prototype.join = function(room, fn){
   debug('joining room %s', room);
   var self = this;
-  if (this.rooms[room]) return this;
+  if (this.rooms.hasOwnProperty(room)) return this;
   this.adapter.add(this.id, room, function(err){
     if (err) return fn && fn(err);
     debug('joined room %s', room);
diff --git a/test/socket.io.js b/test/socket.io.js
index 026cb5f143..c27dff16d0 100644
--- a/test/socket.io.js
+++ b/test/socket.io.js
@@ -1668,6 +1668,23 @@ describe('socket.io', function(){
         });
       });
     });
+
+    it('should not crash when messing with Object prototype', function(done){
+      Object.prototype.foo = 'bar';
+      var srv = http();
+      var sio = io(srv);
+      srv.listen(function(){
+        var socket = client(srv);
+
+        sio.on('connection', function(s){
+          s.disconnect(true);
+          sio.close();
+          setTimeout(function(){
+            done();
+          }, 100);
+        });
+      });
+    });
   });
 
   describe('messaging many', function(){