Detect version in check()

Author: bcoles

modules/exploits/multi/http/cups_bash_env_exec.rb

@@ -83,19 +83,21 @@ def check
     if !res
       vprint_error("#{peer} - No response from host")
       return Exploit::CheckCode::Unknown
-    elsif res.body =~ /Set Default Options for #{printer_name}/
+    elsif res.headers['Server'] =~ /CUPS\/([\d\.]+)/
+      vprint_status("#{peer} - Found CUPS version #{$1}")
+    else
+      print_status("#{peer} - Target is not a CUPS web server")
+      return Exploit::CheckCode::Safe
+    end
+    if res.body =~ /Set Default Options for #{printer_name}/
       vprint_good("#{peer} - Added printer successfully")
       delete_printer(printer_name)
-      return Exploit::CheckCode::Detected
     elsif res.code == 401 || (res.code == 426 && datastore['SSL'] == true)
       vprint_error("#{peer} - Authentication failed")
-      return Exploit::CheckCode::Detected
     elsif res.code == 426
       vprint_error("#{peer} - SSL required - set SSL true")
-      return Exploit::CheckCode::Detected
-    else
-      return Exploit::CheckCode::Safe
     end
+    Exploit::CheckCode::Detected
   end
 
   #