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elastic and opensearch regex fixes, sigma source mapping fix #6

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Merged
merged 1 commit into from
Nov 10, 2023
Merged

elastic and opensearch regex fixes, sigma source mapping fix #6

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5 changes: 3 additions & 2 deletions siem-converter/app/converter/backends/elasticsearch/parsers/elasticsearch.py
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Original file line number Diff line number Diff line change
Expand Up @@ -32,15 +32,16 @@ class ElasticSearchParser(Parser):
mappings: ElasticSearchMappings = elasticsearch_mappings
tokenizer = ElasticSearchTokenizer()

log_source_pattern = r"___source_type___\s*(:|=)\s*(?:\"?(?P<d_q_value>[%a-zA-Z_*:0-9\-/]+)\"|(?P<value>[%a-zA-Z_*:0-9\-/]+))(?:\s+(?:and|or)\s+|\s+)?"
log_source_pattern = r"___source_type___\s*(?:[:=])\s*(?:\"?(?P<d_q_value>[%a-zA-Z_*:0-9\-/]+)\"|(?P<value>[%a-zA-Z_*:0-9\-/]+))(?:\s+(?:and|or)\s+|\s+)?"
log_source_key_types = ("index", "event\.category")

def _parse_log_sources(self, query: str) -> Tuple[str, Dict[str, List[str]]]:
log_sources = {}
for source_type in self.log_source_key_types:
pattern = self.log_source_pattern.replace('___source_type___', source_type)
while search := re.search(pattern, query, flags=re.IGNORECASE):
value = search.group(1)
group_dict = search.groupdict()
value = group_dict.get("d_q_value") or group_dict.get("value")
log_sources.setdefault(source_type, []).append(value)
pos_start = search.start()
pos_end = search.end()
Expand Down
4 changes: 2 additions & 2 deletions siem-converter/app/converter/backends/elasticsearch/tokenizer.py
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Expand Up @@ -32,13 +32,13 @@ class ElasticSearchTokenizer(QueryTokenizer):
match_operator_pattern = r"(?:___field___\s*(?P<match_operator>:))\s*"

num_value_pattern = r"(?P<num_value>\d+(?:\.\d+)*)\s*"
double_quotes_value_pattern = r'"(?P<d_q_value>(?:[:a-zA-Z\*0-9=+%#\-_/,\'\.$&^@!\(\)\{\}\s]|\\\"|\\)+)"\s*'
double_quotes_value_pattern = r'"(?P<d_q_value>(?:[:a-zA-Z\*0-9=+%#\-_/,\'\.$&^@!\(\)\{\}\s]|\\\"|\\)*)"\s*'
no_quotes_value_pattern = r"(?P<n_q_value>(?:[a-zA-Z\*0-9=%#_/,\'\.$@]|\\\"|\\\\)+)\s*"
re_value_pattern = r"/(?P<re_value>[:a-zA-Z\*0-9=+%#\\\-_\,\"\'\.$&^@!\(\)\{\}\[\]\s?]+)/\s*"
_value_pattern = fr"{num_value_pattern}|{re_value_pattern}|{no_quotes_value_pattern}|{double_quotes_value_pattern}"
keyword_pattern = r"(?P<n_q_value>(?:[a-zA-Z\*0-9=%#_/,\'\.$@]|\\\"|\\\(|\\\)|\\\[|\\\]|\\\{|\\\}|\\\:|\\)+)(?:\s+|\)|$)"

multi_value_pattern = r"""\((?P<value>[:a-zA-Z\"\*0-9=+%#\-_\/\\'\,.&^@!\(\[\]\s]*)\)"""
multi_value_pattern = r"""\((?P<value>[:a-zA-Z\"\*0-9=+%#\-_\/\\'\,.&^@!\(\[\]\s]+)\)"""
multi_value_check_pattern = r"___field___\s*___operator___\s*\("

wildcard_symbol = "*"
Expand Down
5 changes: 3 additions & 2 deletions siem-converter/app/converter/backends/opensearch/parsers/opensearch.py
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Original file line number Diff line number Diff line change
Expand Up @@ -32,15 +32,16 @@ class OpenSearchParser(Parser):
mappings: OpenSearchMappings = opensearch_mappings
tokenizer = OpenSearchTokenizer()

log_source_pattern = r"___source_type___\s*(:|=)\s*(?:\"?(?P<d_q_value>[%a-zA-Z_*:0-9\-/]+)\"|(?P<value>[%a-zA-Z_*:0-9\-/]+))(?:\s+(?:and|or)\s+|\s+)?"
log_source_pattern = r"___source_type___\s*(?:[:=])\s*(?:\"?(?P<d_q_value>[%a-zA-Z_*:0-9\-/]+)\"|(?P<value>[%a-zA-Z_*:0-9\-/]+))(?:\s+(?:and|or)\s+|\s+)?"
log_source_key_types = ("index", "event\.category")

def _parse_log_sources(self, query: str) -> Tuple[str, Dict[str, List[str]]]:
log_sources = {}
for source_type in self.log_source_key_types:
pattern = self.log_source_pattern.replace('___source_type___', source_type)
while search := re.search(pattern, query, flags=re.IGNORECASE):
value = search.group(1)
group_dict = search.groupdict()
value = group_dict.get("d_q_value") or group_dict.get("value")
log_sources.setdefault(source_type, []).append(value)
pos_start = search.start()
pos_end = search.end()
Expand Down
4 changes: 2 additions & 2 deletions siem-converter/app/converter/backends/opensearch/tokenizer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -32,13 +32,13 @@ class OpenSearchTokenizer(QueryTokenizer):
match_operator_pattern = r"(?:___field___\s*(?P<match_operator>:))\s*"

num_value_pattern = r"(?P<num_value>\d+(?:\.\d+)*)\s*"
double_quotes_value_pattern = r'"(?P<d_q_value>(?:[:a-zA-Z\*0-9=+%#\-_/,\'\.$&^@!\(\)\{\}\s]|\\\"|\\)+)"\s*'
double_quotes_value_pattern = r'"(?P<d_q_value>(?:[:a-zA-Z\*0-9=+%#\-_/,\'\.$&^@!\(\)\{\}\s]|\\\"|\\)*)"\s*'
no_quotes_value_pattern = r"(?P<n_q_value>(?:[a-zA-Z\*0-9=%#_/,\'\.$@]|\\\"|\\\\)+)\s*"
re_value_pattern = r"/(?P<re_value>[:a-zA-Z\*0-9=+%#\\\-_\,\"\'\.$&^@!\(\)\{\}\[\]\s?]+)/\s*"
_value_pattern = fr"{num_value_pattern}|{re_value_pattern}|{no_quotes_value_pattern}|{double_quotes_value_pattern}"
keyword_pattern = r"(?P<n_q_value>(?:[a-zA-Z\*0-9=%#_/,\'\.$@]|\\\"|\\\(|\\\)|\\\[|\\\]|\\\{|\\\}|\\\:|\\)+)(?:\s+|\)|$)"

multi_value_pattern = r"""\((?P<value>[:a-zA-Z\"\*0-9=+%#\-_\/\\'\,.&^@!\(\[\]\s]*)\)"""
multi_value_pattern = r"""\((?P<value>[:a-zA-Z\"\*0-9=+%#\-_\/\\'\,.&^@!\(\[\]\s]+)\)"""
multi_value_check_pattern = r"___field___\s*___operator___\s*\("

wildcard_symbol = "*"
Expand Down
15 changes: 11 additions & 4 deletions siem-converter/app/converter/backends/sigma/renders/sigma.py
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Original file line number Diff line number Diff line change
Expand Up @@ -17,15 +17,15 @@
"""

import copy
from typing import Any
from typing import Any, List

import yaml

from app.converter.backends.sigma.const import SIGMA_RULE_DETAILS
from app.converter.backends.sigma.mapping import SigmaMappings, sigma_mappings, SigmaLogSourceSignature
from app.converter.core.compiler import DataStructureCompiler
from app.converter.core.exceptions.core import StrictPlatformFieldException
from app.converter.core.mapping import SourceMapping
from app.converter.core.mapping import SourceMapping, DEFAULT_MAPPING_NAME
from app.converter.core.models.field import Field, Keyword
from app.converter.core.models.functions.types import ParsedFunctions
from app.converter.core.models.group import Group
Expand Down Expand Up @@ -229,11 +229,18 @@ def generate_detection(self, data: Any, source_mapping: SourceMapping) -> dict:
self.reset_counters()

return detection

def __get_source_mapping(self, source_mapping_ids: List[str]) -> SourceMapping:
for source_mapping_id in source_mapping_ids:
if source_mapping := self.mappings.get_source_mapping(source_mapping_id):
return source_mapping

return self.mappings.get_source_mapping(DEFAULT_MAPPING_NAME)

def generate(self, query, meta_info: MetaInfoContainer, functions: ParsedFunctions):
self.reset_counters()

source_mapping = self.mappings.get_source_mapping(meta_info.source_mapping_ids[0])
source_mapping = self.__get_source_mapping(meta_info.source_mapping_ids)
log_source_signature: SigmaLogSourceSignature = source_mapping.log_source_signature
sigma_condition = copy.deepcopy(query)
prepared_data_structure = DataStructureCompiler().generate(tokens=sigma_condition)
Expand All @@ -243,7 +250,7 @@ def generate(self, query, meta_info: MetaInfoContainer, functions: ParsedFunctio
"id": meta_info.id,
"description": meta_info.description,
"status": "experimental",
"author": "",
"author": meta_info.author,
"references": meta_info.references,
"tags": meta_info.tags,
"logsource": log_source_signature.log_sources,
Expand Down
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