diff --git a/modules/exploits/windows/scada/codesys_web_server.rb b/modules/exploits/windows/scada/codesys_web_server.rb
index 4b6169d434..770a983458 100644
--- a/modules/exploits/windows/scada/codesys_web_server.rb
+++ b/modules/exploits/windows/scada/codesys_web_server.rb
@@ -29,7 +29,7 @@ class Metasploit3 < Msf::Exploit::Remote
 				],
 			'References'      =>
 				[
-					[ 'OSVDB', 77387'],
+					[ 'OSVDB', '77387'],
 					[ 'URL', 'http://aluigi.altervista.org/adv/codesys_1-adv.txt' ],
 					[ 'URL', 'http://www.exploit-db.com/exploits/18187/' ],
 					[ 'URL', 'http://www.us-cert.gov/control_systems/pdf/ICS-ALERT-11-336-01A.pdf' ]