"""
Copyright (c) 2006-2025 sqlmap developers (https://sqlmap.org)
See the file 'doc/COPYING' for copying permission
"""
from lib.core.compat import xrange
from lib.core.enums import PRIORITY
from lib.core.settings import REPLACEMENT_MARKER
__priority__ = PRIORITY.HIGHEST
def dependencies():
pass
def tamper(payload, **kwargs):
"""
Replaces instances like 'IF(A, B, C)' with 'CASE WHEN (A) THEN (B) ELSE (C) END' counterpart
Requirement:
* MySQL
* SQLite (possibly)
* SAP MaxDB (possibly)
Tested against:
* MySQL 5.0 and 5.5
Notes:
* Useful to bypass very weak and bespoke web application firewalls
that filter the IF() functions
>>> tamper('IF(1, 2, 3)')
'CASE WHEN (1) THEN (2) ELSE (3) END'
>>> tamper('SELECT IF((1=1), (SELECT "foo"), NULL)')
'SELECT CASE WHEN (1=1) THEN (SELECT "foo") ELSE (NULL) END'
"""
if payload and payload.find("IF") > -1:
payload = payload.replace("()", REPLACEMENT_MARKER)
while payload.find("IF(") > -1:
index = payload.find("IF(")
depth = 1
commas, end = [], None
for i in xrange(index + len("IF("), len(payload)):
if depth == 1 and payload[i] == ',':
commas.append(i)
elif depth == 1 and payload[i] == ')':
end = i
break
elif payload[i] == '(':
depth += 1
elif payload[i] == ')':
depth -= 1
if len(commas) == 2 and end:
a = payload[index + len("IF("):commas[0]].strip("()")
b = payload[commas[0] + 1:commas[1]].lstrip().strip("()")
c = payload[commas[1] + 1:end].lstrip().strip("()")
newVal = "CASE WHEN (%s) THEN (%s) ELSE (%s) END" % (a, b, c)
payload = payload[:index] + newVal + payload[end + 1:]
else:
break
payload = payload.replace(REPLACEMENT_MARKER, "()")
return payload
