Minor fix for --dump --technique=B when empty strings are returned

lib/request/inject.py

@@ -437,7 +437,7 @@ def getValue(expression, blind=True, inband=True, error=True, time=True, fromUse
                     value = __goInferenceProxy(query, fromUser, batch, unpack, charsetType, firstChar, lastChar, dump)
 
             if value and isinstance(value, basestring):
-                value = value.strip()
+                value = value.strip() if value.strip() else value[:1]
         else:
             errMsg = "none of the injection types identified can be "
             errMsg += "leveraged to retrieve queries output"

plugins/generic/entries.py

@@ -285,6 +285,7 @@ class Entries:
                                         query = rootQuery.blind.query % (index, column, tbl)
 
                                     value = NULL if column in emptyColumns else inject.getValue(query, inband=False, error=False, dump=True)
+                                    value = '' if value is None else value
 
                                     _ = DUMP_REPLACEMENTS.get(getUnicode(value), getUnicode(value))
                                     lengths[column] = max(lengths[column], len(_))