diff --git a/lib/core/common.py b/lib/core/common.py
index 636703505..6d69fbfd7 100755
--- a/lib/core/common.py
+++ b/lib/core/common.py
@@ -989,7 +989,7 @@ def checkFile(filename):
     Checks for file existence
     """
 
-    if not os.path.isfile(filename):
+    if filename is None or not os.path.isfile(filename):
         raise SqlmapFilePathException("unable to read file '%s'" % filename)
 
 def banner():
diff --git a/lib/utils/hash.py b/lib/utils/hash.py
index 0c76bff5b..e414e7239 100644
--- a/lib/utils/hash.py
+++ b/lib/utils/hash.py
@@ -750,6 +750,8 @@ def dictionaryAttack(attack_dict):
                     else:
                         logger.info("using default dictionary")
 
+                    dictPaths = filter(None, dictPaths)
+
                     for dictPath in dictPaths:
                         checkFile(dictPath)