Add error handling to get_once

And check for specific ack result/reason for 32-bit.

Author: wvu

modules/exploits/windows/smb/ms17_010_eternalblue.rb

@@ -269,7 +269,14 @@ def verify_arch
     )
 
     sock.put(pkt)
-    res = sock.get_once
+
+    begin
+      res = sock.get_once(60)
+    rescue EOFError
+      print_error('DCE/RPC socket returned EOFError')
+      return false
+    end
+
     disconnect(sock)
 
     begin
@@ -287,7 +294,8 @@ def verify_arch
       end
     when ARCH_X86
       # Ack result: Provider rejection (2)
-      if resp.ack_result.first != 0
+      # Ack reason: Proposed transfer syntaxes not supported (2)
+      if resp.ack_result.first == 2 && resp.ack_reason.first == 2
         ret = true
       end
     end