#!/usr/bin/env python3 """ Checks for noncompliance or common errors on all rules Run using the command # python test_rules.py """ import os import unittest import yaml import re from attackcti import attack_client from colorama import init from colorama import Fore import collections class TestRules(unittest.TestCase): @classmethod def setUpClass(cls): print("Calling get_mitre_data()") # Get Current Data from MITRE ATT&CK® cls.MITRE_ALL = get_mitre_data() print("Catched data - starting tests...") MITRE_TECHNIQUE_NAMES = [ "process_injection", "signed_binary_proxy_execution", "process_injection"] # incomplete list MITRE_TACTICS = ["initial_access", "execution", "persistence", "privilege_escalation", "defense_evasion", "credential_access", "discovery", "lateral_movement", "collection", "exfiltration", "command_and_control", "impact", "launch"] # Don't use trademarks in rules - they require non-ASCII characters to be used on we don't want them in our rules TRADE_MARKS = {"MITRE ATT&CK", "ATT&CK"} path_to_rules = "rules" # Helper functions def yield_next_rule_file_path(self, path_to_rules: str) -> str: for root, _, files in os.walk(path_to_rules): for file in files: yield os.path.join(root, file) def get_rule_part(self, file_path: str, part_name: str): yaml_dicts = self.get_rule_yaml(file_path) for yaml_part in yaml_dicts: if part_name in yaml_part.keys(): return yaml_part[part_name] return None def get_rule_yaml(self, file_path: str) -> dict: data = [] with open(file_path, encoding='utf-8') as f: yaml_parts = yaml.safe_load_all(f) for part in yaml_parts: data.append(part) return data # Tests # def test_confirm_extension_is_yml(self): # files_with_incorrect_extensions = [] # for file in self.yield_next_rule_file_path(self.path_to_rules): # file_name_and_extension = os.path.splitext(file) # if len(file_name_and_extension) == 2: # extension = file_name_and_extension[1] # if extension != ".yml": # files_with_incorrect_extensions.append(file) # self.assertEqual(files_with_incorrect_extensions, [], Fore.RED + # "There are rule files with extensions other than .yml") def test_legal_trademark_violations(self): # See Issue # https://github.com/SigmaHQ/sigma/issues/1028 files_with_legal_issues = [] for file in self.yield_next_rule_file_path(self.path_to_rules): with open(file, 'r', encoding='utf-8') as fh: file_data = fh.read() for tm in self.TRADE_MARKS: if tm in file_data: files_with_legal_issues.append(file) self.assertEqual(files_with_legal_issues, [], Fore.RED + "There are rule files which contains a trademark or reference that doesn't comply with the respective trademark requirements - please remove the trademark to avoid legal issues") def test_optional_tags(self): files_with_incorrect_tags = [] tags_pattern = re.compile( r"cve\.\d+\.\d+|attack\.(t\d{4}\.\d{3}|[gts]\d{4})$|attack\.[a-z_]+|car\.\d{4}-\d{2}-\d{3}") for file in self.yield_next_rule_file_path(self.path_to_rules): tags = self.get_rule_part(file_path=file, part_name="tags") if tags: for tag in tags: if tags_pattern.match(tag) == None: print( Fore.RED + "Rule {} has the invalid tag <{}>".format(file, tag)) files_with_incorrect_tags.append(file) self.assertEqual(files_with_incorrect_tags, [], Fore.RED + "There are rules with incorrect/unknown MITRE Tags. (please inform us about new tags that are not yet supported in our tests) and check the correct tags here: https://attack.mitre.org/ ") def test_confirm_correct_mitre_tags(self): files_with_incorrect_mitre_tags = [] for file in self.yield_next_rule_file_path(self.path_to_rules): tags = self.get_rule_part(file_path=file, part_name="tags") if tags: for tag in tags: if tag not in self.MITRE_ALL and tag.startswith("attack."): print( Fore.RED + "Rule {} has the following incorrect tag {}".format(file, tag)) files_with_incorrect_mitre_tags.append(file) self.assertEqual(files_with_incorrect_mitre_tags, [], Fore.RED + "There are rules with incorrect/unknown MITRE Tags. (please inform us about new tags that are not yet supported in our tests) and check the correct tags here: https://attack.mitre.org/ ") def test_duplicate_tags(self): files_with_incorrect_mitre_tags = [] for file in self.yield_next_rule_file_path(self.path_to_rules): tags = self.get_rule_part(file_path=file, part_name="tags") if tags: known_tags = [] for tag in tags: if tag in known_tags: print( Fore.RED + "Rule {} has the duplicate tag {}".format(file, tag)) files_with_incorrect_mitre_tags.append(file) else: known_tags.append(tag) self.assertEqual(files_with_incorrect_mitre_tags, [], Fore.RED + "There are rules with duplicate tags") def test_look_for_duplicate_filters(self): def check_list_or_recurse_on_dict(item, depth: int, special: bool) -> None: if type(item) == list: check_if_list_contain_duplicates(item, depth, special) elif type(item) == dict and depth <= MAX_DEPTH: for keys, sub_item in item.items(): if "|base64" in keys: # Covers both "base64" and "base64offset" modifiers check_list_or_recurse_on_dict(sub_item, depth + 1, True) else: check_list_or_recurse_on_dict(sub_item, depth + 1, special) def check_if_list_contain_duplicates(item: list, depth: int, special: bool) -> None: try: # We use a list comprehension to convert all the element to lowercase. Since we don't care about casing in SIGMA except for the following modifiers # - "base64offset" # - "base64" if special: item_ = item else: item_= [i.lower() for i in item] if len(item_) != len(set(item_)): # We find the duplicates and then print them to the user duplicates = [i for i, count in collections.Counter(item_).items() if count > 1] print(Fore.RED + "Rule {} has duplicate filters {}".format(file, duplicates)) files_with_duplicate_filters.append(file) except: # unhashable types like dictionaries for sub_item in item: if type(sub_item) == dict and depth <= MAX_DEPTH: check_list_or_recurse_on_dict(sub_item, depth + 1, special) MAX_DEPTH = 3 files_with_duplicate_filters = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") check_list_or_recurse_on_dict(detection, 1, False) self.assertEqual(files_with_duplicate_filters, [], Fore.RED + "There are rules with duplicate filters") def test_field_name_with_space(self): def key_iterator(fields, faulty): for key, value in fields.items(): if " " in key: faulty.append(key) print( Fore.YELLOW + "Rule {} has a space in field name ({}).".format(file, key)) if type(value) == dict: key_iterator(value, faulty) faulty_fieldnames = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") key_iterator(detection, faulty_fieldnames) self.assertEqual(faulty_fieldnames, [], Fore.RED + "There are rules with an unsupported field name. Spaces are not allowed. (Replace space with an underscore character '_' )") def test_single_named_condition_with_x_of_them(self): faulty_detections = [] for file in self.yield_next_rule_file_path(self.path_to_rules): yaml = self.get_rule_yaml(file_path=file) detection = self.get_rule_part( file_path=file, part_name="detection") has_them_in_condition = "them" in detection["condition"] has_only_one_named_condition = len(detection) == 2 not_multipart_yaml_file = len(yaml) == 1 if has_them_in_condition and \ has_only_one_named_condition and \ not_multipart_yaml_file: faulty_detections.append(file) self.assertEqual(faulty_detections, [], Fore.RED + "There are rules using '1/all of them' style conditions but only have one condition") def test_all_of_them_condition(self): faulty_detections = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") if "all of them" in detection["condition"]: faulty_detections.append(file) self.assertEqual(faulty_detections, [], Fore.RED + "There are rules using 'all of them'. Better use e.g. 'all of selection*' instead (and use the 'selection_' prefix as search-identifier).") def test_duplicate_detections(self): def compare_detections(detection1: dict, detection2: dict) -> bool: # detections not the same count can't be the same if len(detection1) != len(detection2): return False for named_condition in detection1: # don't check timeframes if named_condition == "timeframe": continue # condition clause must be the same too if named_condition == "condition": if detection1["condition"] != detection2["condition"]: return False else: continue # Named condition must exist in both rule files if named_condition not in detection2: return False # can not be the same if len is not equal if len(detection1[named_condition]) != len(detection2[named_condition]): return False for condition in detection1[named_condition]: if type(condition) != str: return False if condition not in detection2[named_condition]: return False condition_value1 = detection1[named_condition][condition] condition_value2 = detection2[named_condition][condition] if condition_value1 != condition_value2: return False return True faulty_detections = [] files_and_their_detections = {} for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") logsource = self.get_rule_part( file_path=file, part_name="logsource") detection["logsource"] = {} detection["logsource"].update(logsource) yaml = self.get_rule_yaml(file_path=file) is_multipart_yaml_file = len(yaml) != 1 if is_multipart_yaml_file: continue for key in files_and_their_detections: if compare_detections(detection, files_and_their_detections[key]): faulty_detections.append((key, file)) files_and_their_detections[file] = detection self.assertEqual(faulty_detections, [], Fore.YELLOW + "There are rule files with exactly the same detection logic.") def test_source_eventlog(self): faulty_detections = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") detection_str = str(detection).lower() if "'source': 'eventlog'" in detection_str: faulty_detections.append(file) self.assertEqual(faulty_detections, [], Fore.YELLOW + "There are detections with 'Source: Eventlog'. This does not add value to the detection.") def test_event_id_instead_of_process_creation(self): faulty_detections = [] for file in self.yield_next_rule_file_path(self.path_to_rules): with open(file, encoding='utf-8') as f: for line in f: if re.search(r'.*EventID: (?:1|4688)\s*$', line) and file not in faulty_detections: detection = self.get_rule_part(file_path=file, part_name="detection") if detection: for search_identifier in detection: if isinstance(detection[search_identifier], dict): for field in detection[search_identifier]: if "Provider_Name" in field: if isinstance(detection[search_identifier]["Provider_Name"], list): for value in detection[search_identifier]["Provider_Name"]: if "Microsoft-Windows-Security-Auditing" in value or "Microsoft-Windows-Sysmon" in value: if file not in faulty_detections: faulty_detections.append(file) else: if "Microsoft-Windows-Security-Auditing" in detection[search_identifier]["Provider_Name"] or "Microsoft-Windows-Sysmon" in detection[search_identifier]["Provider_Name"]: if file not in faulty_detections: faulty_detections.append(file) self.assertEqual(faulty_detections, [], Fore.YELLOW + "There are rules still using Sysmon 1 or Event ID 4688. Please migrate to the process_creation category.") def test_missing_id(self): faulty_rules = [] dict_id = {} for file in self.yield_next_rule_file_path(self.path_to_rules): id = self.get_rule_part(file_path=file, part_name="id") if not id: print(Fore.YELLOW + "Rule {} has no field 'id'.".format(file)) faulty_rules.append(file) elif len(id) != 36: print( Fore.YELLOW + "Rule {} has a malformed 'id' (not 36 chars).".format(file)) faulty_rules.append(file) elif id.lower() in dict_id.keys(): print( Fore.YELLOW + "Rule {} has the same 'id' than {} must be unique.".format(file, dict_id[id])) faulty_rules.append(file) else: dict_id[id.lower()] = file self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with missing or malformed 'id' fields. Create an id (e.g. here: https://www.uuidgenerator.net/version4) and add it to the reported rule(s).") def test_optional_related(self): faulty_rules = [] valid_type = [ "derived", "obsoletes", "merged", "renamed", "similar" ] for file in self.yield_next_rule_file_path(self.path_to_rules): related_lst = self.get_rule_part( file_path=file, part_name="related") if related_lst: # it exists but isn't a list if not isinstance(related_lst, list): print( Fore.YELLOW + "Rule {} has a 'related' field that isn't a list.".format(file)) faulty_rules.append(file) else: # should probably test if we have only 'id' and 'type' ... type_ok = True for ref in related_lst: id_str = ref['id'] type_str = ref['type'] if not type_str in valid_type: type_ok = False # Only add one time if many bad type in the same file if type_ok == False: print( Fore.YELLOW + "Rule {} has a 'related/type' invalid value.".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed optional 'related' fields. (check https://github.com/SigmaHQ/sigma/wiki/Specification)") def test_sysmon_rule_without_eventid(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): logsource = self.get_rule_part( file_path=file, part_name="logsource") if logsource: service = logsource.get('service', '') if service.lower() == 'sysmon': with open(file, encoding='utf-8') as f: found = False for line in f: # might be on a single line or in multiple lines if re.search(r'.*EventID:.*$', line): found = True break if not found: faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules using sysmon events but with no EventID specified") def test_missing_date(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): datefield = self.get_rule_part(file_path=file, part_name="date") if not datefield: print(Fore.YELLOW + "Rule {} has no field 'date'.".format(file)) faulty_rules.append(file) elif not isinstance(datefield, str): print( Fore.YELLOW + "Rule {} has a malformed 'date' (should be YYYY/MM/DD).".format(file)) faulty_rules.append(file) elif len(datefield) != 10: print( Fore.YELLOW + "Rule {} has a malformed 'date' (not 10 chars, should be YYYY/MM/DD).".format(file)) faulty_rules.append(file) elif datefield[4] != '/' or datefield[7] != '/': print( Fore.YELLOW + "Rule {} has a malformed 'date' (should be YYYY/MM/DD).".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with missing or malformed 'date' fields. (create one, e.g. date: 2019/01/14)") def test_missing_description(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): descriptionfield = self.get_rule_part( file_path=file, part_name="description") if not descriptionfield: print(Fore.YELLOW + "Rule {} has no field 'description'.".format(file)) faulty_rules.append(file) elif not isinstance(descriptionfield, str): print( Fore.YELLOW + "Rule {} has a 'description' field that isn't a string.".format(file)) faulty_rules.append(file) elif len(descriptionfield) < 16: print( Fore.YELLOW + "Rule {} has a really short description. Please elaborate.".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with missing or malformed 'description' field. (create one, e.g. description: Detects the suspicious behaviour of process XY doing YZ)") def test_optional_date_modified(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): modifiedfield = self.get_rule_part( file_path=file, part_name="modified") if modifiedfield: if not isinstance(modifiedfield, str): print( Fore.YELLOW + "Rule {} has a malformed 'modified' (should be YYYY/MM/DD).".format(file)) faulty_rules.append(file) elif len(modifiedfield) != 10: print( Fore.YELLOW + "Rule {} has a malformed 'modified' (not 10 chars, should be YYYY/MM/DD).".format(file)) faulty_rules.append(file) elif modifiedfield[4] != '/' or modifiedfield[7] != '/': print( Fore.YELLOW + "Rule {} has a malformed 'modified' (should be YYYY/MM/DD).".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed 'modified' fields. (create one, e.g. date: 2019/01/14)") def test_optional_status(self): faulty_rules = [] valid_status = [ "stable", "test", "experimental", "deprecated", "unsupported" ] for file in self.yield_next_rule_file_path(self.path_to_rules): status_str = self.get_rule_part(file_path=file, part_name="status") if status_str: if not status_str in valid_status: print( Fore.YELLOW + "Rule {} has a invalid 'status' (check wiki).".format(file)) faulty_rules.append(file) elif status_str == "unsupported": print( Fore.YELLOW + "Rule {} has the unsupported 'status', can not be in rules directory".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed 'status' fields. (check https://github.com/SigmaHQ/sigma/wiki/Specification)") def test_level(self): faulty_rules = [] valid_level = [ "informational", "low", "medium", "high", "critical", ] for file in self.yield_next_rule_file_path(self.path_to_rules): level_str = self.get_rule_part(file_path=file, part_name="level") if not level_str: print(Fore.YELLOW + "Rule {} has no field 'level'.".format(file)) faulty_rules.append(file) elif not level_str in valid_level: print( Fore.YELLOW + "Rule {} has a invalid 'level' (check wiki).".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with missing or malformed 'level' fields. (check https://github.com/SigmaHQ/sigma/wiki/Specification)") def test_optional_fields(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): fields_str = self.get_rule_part(file_path=file, part_name="fields") if fields_str: # it exists but isn't a list if not isinstance(fields_str, list): print( Fore.YELLOW + "Rule {} has a 'fields' field that isn't a list.".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed optional 'fields' fields. (has to be a list of values even if it contains only a single value)") def test_optional_falsepositives_listtype(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): falsepositives_str = self.get_rule_part( file_path=file, part_name="falsepositives") if falsepositives_str: # it exists but isn't a list if not isinstance(falsepositives_str, list): print( Fore.YELLOW + "Rule {} has a 'falsepositives' field that isn't a list.".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed optional 'falsepositives' fields. (has to be a list of values even if it contains only a single value)") def test_optional_falsepositives_capital(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): fps = self.get_rule_part( file_path=file, part_name="falsepositives") if fps: for fp in fps: # first letter should be capital try: if fp[0].upper() != fp[0]: print( Fore.YELLOW + "Rule {} defines a falsepositive that does not start with a capital letter: '{}'.".format(file, fp)) faulty_rules.append(file) except TypeError as err: print("TypeError Exception for rule {}".format(file)) print("Error: {}".format(err)) print("Maybe you created an empty falsepositive item?") self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with false positives that don't start with a capital letter (e.g. 'unknown' should be 'Unknown')") def test_optional_falsepositives_blocked_content(self): faulty_rules = [] banned_words = ["none", "pentest", "penetration test"] common_typos = ["unkown", "ligitimate", "legitim ", "legitimeate"] for file in self.yield_next_rule_file_path(self.path_to_rules): fps = self.get_rule_part( file_path=file, part_name="falsepositives") if fps: for fp in fps: for typo in common_typos: if fp == "Unknow" or typo in fp.lower(): print( Fore.YELLOW + "Rule {} defines a falsepositive with a common typo: '{}'.".format(file, typo)) faulty_rules.append(file) for banned_word in banned_words: if banned_word in fp.lower(): print( Fore.YELLOW + "Rule {} defines a falsepositive with an invalid reason: '{}'.".format(file, banned_word)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with invalid false positive definitions (e.g. Pentest, None or common typos)") # Upgrade Detection Rule License 1.1 def test_optional_author(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): author_str = self.get_rule_part(file_path=file, part_name="author") if author_str: # it exists but isn't a string if not isinstance(author_str, str): print( Fore.YELLOW + "Rule {} has a 'author' field that isn't a string.".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed 'author' fields. (has to be a string even if it contains many author)") def test_optional_license(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): license_str = self.get_rule_part( file_path=file, part_name="license") if license_str: if not isinstance(license_str, str): print( Fore.YELLOW + "Rule {} has a malformed 'license' (has to be a string).".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed 'license' fields. (has to be a string )") def test_optional_tlp(self): faulty_rules = [] valid_tlp = [ "WHITE", "GREEN", "AMBER", "RED", ] for file in self.yield_next_rule_file_path(self.path_to_rules): tlp_str = self.get_rule_part(file_path=file, part_name="tlp") if tlp_str: # it exists but isn't a string if not isinstance(tlp_str, str): print( Fore.YELLOW + "Rule {} has a 'tlp' field that isn't a string.".format(file)) faulty_rules.append(file) elif not tlp_str.upper() in valid_tlp: print( Fore.YELLOW + "Rule {} has a 'tlp' field with not valid value.".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed optional 'tlp' fields. (https://www.cisa.gov/tlp)") def test_optional_target(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): target = self.get_rule_part(file_path=file, part_name="target") if target: # it exists but isn't a list if not isinstance(target, list): print( Fore.YELLOW + "Rule {} has a 'target' field that isn't a list.".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed 'target' fields. (has to be a list of values even if it contains only a single value)") def test_references(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): references = self.get_rule_part( file_path=file, part_name="references") # Reference field doesn't exist # if not references: # print(Fore.YELLOW + "Rule {} has no field 'references'.".format(file)) # faulty_rules.append(file) if references: # it exists but isn't a list if not isinstance(references, list): print( Fore.YELLOW + "Rule {} has a references field that isn't a list.".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed 'references' fields. (has to be a list of values even if it contains only a single value)") def test_references_in_description(self): # This test checks for the presence of a links and special keywords in the "description" field while there is no "references" field. faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): references = self.get_rule_part( file_path=file, part_name="references") # Reference field doesn't exist if not references: descriptionfield = self.get_rule_part( file_path=file, part_name="description") if descriptionfield: for i in ["http://", "https://", "internal research"]: # Extends the list with other common references starters if i in descriptionfield.lower(): print(Fore.RED + "Rule {} has a field that contains references to external links but no references set. Add a 'references' key and add URLs as list items.".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed 'description' fields. (links and external references have to be in a seperate field named 'references'. see specification https://github.com/SigmaHQ/sigma-specification)") def test_references_plural(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): reference = self.get_rule_part( file_path=file, part_name="reference") if reference: # it exists but in singular form faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with malformed 'references' fields. (has to be 'references' in plural form, not singular)") def test_file_names(self): faulty_rules = [] name_lst = [] filename_pattern = re.compile(r'[a-z0-9_]{10,70}\.yml') for file in self.yield_next_rule_file_path(self.path_to_rules): filename = os.path.basename(file) if filename in name_lst: print(Fore.YELLOW + "Rule {} is a duplicate file name.".format(file)) faulty_rules.append(file) elif filename[-4:] != ".yml": print(Fore.YELLOW + "Rule {} has a invalid extension (.yml).".format(file)) faulty_rules.append(file) elif len(filename) > 74: print(Fore.YELLOW + "Rule {} has a file name too long >70.".format(file)) faulty_rules.append(file) elif len(filename) < 14: print(Fore.YELLOW + "Rule {} has a file name too short <10.".format(file)) faulty_rules.append(file) elif filename_pattern.match(filename) == None or not '_' in filename: print( Fore.YELLOW + "Rule {} has a file name that doesn't match our standard.".format(file)) faulty_rules.append(file) else: # This test make sure that every rules has a filename that corresponds to # It's specific logsource. # Fix Issue #1381 (https://github.com/SigmaHQ/sigma/issues/1381) logsource = self.get_rule_part(file_path=file, part_name="logsource") if logsource: pattern_prefix = "" os_infix = "" os_bool = False for key,value in logsource.items(): if key == "definition": pass else: if key == "product": # This is to get the OS for certain categories if value == "windows": os_infix = "win_" elif value == "macos": os_infix = "macos_" elif value == "linux": os_infix = "lnx_" # For other stuff elif value == "aws": pattern_prefix = "aws_" elif value == "azure": pattern_prefix = "azure_" elif value == "gcp": pattern_prefix = "gcp_" elif value == "gworkspace": pattern_prefix = "gworkspace_" elif value == "m365": pattern_prefix = "microsoft365_" elif value == "okta": pattern_prefix = "okta_" elif value == "onelogin": pattern_prefix = "onelogin_" elif key == "category": if value == "process_creation": pattern_prefix = "proc_creation_" os_bool = True elif value == "image_load": pattern_prefix = "image_load_" elif value == "file_event": pattern_prefix = "file_event_" os_bool = True elif value == "registry_set": pattern_prefix = "registry_set_" elif value == "registry_add": pattern_prefix = "registry_add_" elif value == "registry_event": pattern_prefix = "registry_event_" elif value == "registry_delete": pattern_prefix = "registry_delete_" elif value == "registry_rename": pattern_prefix = "registry_rename_" elif value == "process_access": pattern_prefix = "proc_access_" os_bool = True elif value == "driver_load": pattern_prefix = "driver_load_" os_bool = True elif value == "dns_query": pattern_prefix = "dns_query_" os_bool = True elif value == "ps_script": pattern_prefix = "posh_ps_" elif value == "ps_module": pattern_prefix = "posh_pm_" elif value == "ps_classic_start": pattern_prefix = "posh_pc_" elif value == "pipe_created": pattern_prefix = "pipe_created_" elif value == "network_connection": pattern_prefix = "net_connection_" os_bool = True elif value == "file_rename": pattern_prefix = "file_rename_" os_bool = True elif value == "file_delete": pattern_prefix = "file_delete_" os_bool = True elif value == "file_change": pattern_prefix = "file_change_" os_bool = True elif value == "file_access": pattern_prefix = "file_access_" os_bool = True elif value == "create_stream_hash": pattern_prefix = "create_stream_hash_" elif value == "create_remote_thread": pattern_prefix = "create_remote_thread_win_" elif value == "dns": pattern_prefix = "net_dns_" elif value == "firewall": pattern_prefix = "net_firewall_" elif value == "webserver": pattern_prefix = "web_" elif key == "service": if value == "auditd": pattern_prefix = "lnx_auditd_" elif value == "modsecurity": pattern_prefix = "modsec_" elif value == "diagnosis-scripted": pattern_prefix = "win_diagnosis_scripted_" elif value == "firewall-as": pattern_prefix = "win_firewall_as_" elif value == "msexchange-management": pattern_prefix = "win_exchange_" elif value == "security": pattern_prefix = "win_security_" elif value == "system": pattern_prefix = "win_system_" elif value == "taskscheduler": pattern_prefix = "win_taskscheduler_" elif value == "terminalservices-localsessionmanager": pattern_prefix = "win_terminalservices_" elif value == "windefend": pattern_prefix = "win_defender_" elif value == "wmi": pattern_prefix = "win_wmi_" elif value == "codeintegrity-operational": pattern_prefix = "win_codeintegrity_" elif value == "bits-client": pattern_prefix = "win_bits_client_" elif value == "applocker": pattern_prefix = "win_applocker_" elif value == "dns-server-analytic": pattern_prefix = "win_dns_analytic_" elif value == "bitlocker": pattern_prefix = "win_bitlocker_" # This value is used to test if we should add the OS infix for certain categories if os_bool: pattern_prefix += os_infix if pattern_prefix != "": if not filename.startswith(pattern_prefix): print( Fore.YELLOW + "Rule {} has a file name that doesn't match our standard naming convention.".format(file)) faulty_rules.append(file) name_lst.append(filename) self.assertEqual(faulty_rules, [], Fore.RED + r'There are rules with malformed file names (too short, too long, uppercase letters, a minus sign etc.). Please see the file names used in our repository and adjust your file names accordingly. The pattern for a valid file name is \'[a-z0-9_]{10,70}\.yml\' and it has to contain at least an underline character. It also has to follow the following naming convention https://github.com/SigmaHQ/sigma-specification/blob/main/sigmahq/Sigmahq_filename_rule.md') def test_title(self): faulty_rules = [] allowed_lowercase_words = [ 'the', 'for', 'in', 'with', 'via', 'on', 'to', 'without', 'of', 'through', 'from', 'by', 'as', 'a', 'or', 'at', 'and', 'an', 'over', 'new', ] for file in self.yield_next_rule_file_path(self.path_to_rules): title = self.get_rule_part(file_path=file, part_name="title") if not title: print(Fore.RED + "Rule {} has no field 'title'.".format(file)) faulty_rules.append(file) continue elif len(title) > 70: print(Fore.YELLOW + "Rule {} has a title field with too many characters (>70)".format(file)) faulty_rules.append(file) if title.startswith("Detects "): print(Fore.RED + "Rule {} has a title that starts with 'Detects'".format(file)) faulty_rules.append(file) if title.endswith("."): print(Fore.RED + "Rule {} has a title that ends with '.'".format(file)) faulty_rules.append(file) wrong_casing = [] for word in title.split(" "): if word.islower() and not word.lower() in allowed_lowercase_words and not "." in word and not "/" in word and not word[0].isdigit(): wrong_casing.append(word) if len(wrong_casing) > 0: print(Fore.RED + "Rule {} has a title that has not title capitalization. Words: '{}'".format( file, ", ".join(wrong_casing))) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with non-conform 'title' fields. Please check: https://github.com/SigmaHQ/sigma/wiki/Rule-Creation-Guide#title") def test_title_in_first_line(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): yaml = self.get_rule_yaml(file) # skip multi-part yaml if len(yaml) > 1: continue # this probably is not the best way to check whether # title is the attribute given in the 1st line # (also assumes dict keeps the order from the input file) if list(yaml[0].keys())[0] != "title": print( Fore.RED + "Rule {} does not have its 'title' attribute in the first line".format(file)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules without the 'title' attribute in their first line.") def test_duplicate_titles(self): # This test ensure that every rule has a unique title faulty_rules = [] titles_dict = {} for file in self.yield_next_rule_file_path(self.path_to_rules): title = self.get_rule_part(file_path=file, part_name="title").lower().rstrip() duplicate = False for rule, title_ in titles_dict.items(): if title == title_: print(Fore.RED + "Rule {} has an already used title in {}.".format(file, rule)) duplicate = True faulty_rules.append(file) continue if not duplicate: titles_dict[file] = title self.assertEqual(faulty_rules, [], Fore.RED + "There are rules that share the same 'title'. Please check: https://github.com/SigmaHQ/sigma/wiki/Rule-Creation-Guide#title") # def test_invalid_logsource_attributes(self): # faulty_rules = [] # valid_logsource = [ # 'category', # 'product', # 'service', # 'definition', # ] # for file in self.yield_next_rule_file_path(self.path_to_rules): # logsource = self.get_rule_part( # file_path=file, part_name="logsource") # if not logsource: # print(Fore.RED + "Rule {} has no 'logsource'.".format(file)) # faulty_rules.append(file) # continue # valid = True # for key in logsource: # if key.lower() not in valid_logsource: # print( # Fore.RED + "Rule {} has a logsource with an invalid field ({})".format(file, key)) # valid = False # elif not isinstance(logsource[key], str): # print( # Fore.RED + "Rule {} has a logsource with an invalid field type ({})".format(file, key)) # valid = False # if not valid: # faulty_rules.append(file) # self.assertEqual(faulty_rules, [], Fore.RED + # "There are rules with non-conform 'logsource' fields. Please check: https://github.com/SigmaHQ/sigma/wiki/Rule-Creation-Guide#log-source") def test_selection_list_one_value(self): def treat_list(file, values, valid_, selection_name): # rule with only list of Keywords term if len(values) == 1 and not isinstance(values[0], str): print( Fore.RED + "Rule {} has the selection ({}) with a list of only 1 element in detection".format(file, key) ) valid_ = False elif isinstance(values[0], dict): valid_ = treat_dict(file, values, valid_, selection_name) return valid_ def treat_dict(file, values, valid_, selection_name): if isinstance(values, list): for dict_ in values: for key_ in dict_.keys(): if isinstance(dict_[key_], list): if len(dict_[key_]) == 1: print( Fore.RED + "Rule {} has the selection ({}/{}) with a list of only 1 value in detection".format(file, selection_name, key_) ) valid_ = False else: dict_ = values for key_ in dict_.keys(): if isinstance(dict_[key_], list): if len(dict_[key_]) == 1: print( Fore.RED + "Rule {} has the selection ({}/{}) with a list of only 1 value in detection".format(file, selection_name, key_) ) valid_ = False return valid_ faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") if detection: valid = True for key in detection: values = detection[key] if isinstance(detection[key], list): valid = treat_list(file, values, valid, key) if isinstance(detection[key], dict): valid = treat_dict(file, values, valid, key) if not valid: faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules using list with only 1 element") def test_selection_start_or_and(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") if detection: # This test is a best effort to avoid breaking SIGMAC parser. You could do more testing and try to fix this once and for all by modifiying the token regular expressions https://github.com/SigmaHQ/sigma/blob/b9ae5303f12cda8eb6b5b90a32fd7f11ad65645d/tools/sigma/parser/condition.py#L107-L127 for key in detection: if key[:3].lower() == "sel": continue elif key[:2].lower() == "or": print( Fore.RED + "Rule {} has a selection '{}' that starts with the string 'or'".format(file, key)) faulty_rules.append(file) elif key[:3].lower() == "and": print( Fore.RED + "Rule {} has a selection '{}' that starts with the string 'and'".format(file, key)) faulty_rules.append(file) elif key[:3].lower() == "not": print( Fore.RED + "Rule {} has a selection '{}' that starts with the string 'not'".format(file, key)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with bad selection names. Can't start a selection name with an 'or*' or an 'and*' or a 'not*' ") def test_unused_selection(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") condition = detection["condition"] wildcard_selections = re.compile(r"\sof\s([\w\*]+)(?:$|\s|\))") # skip rules containing aggregations if type(condition) == list: continue for selection in detection: if selection == "condition": continue if selection == "timeframe": continue # remove special keywords condition_list = condition.replace("not ", '').replace("1 of ", '').replace("all of ", '').replace(' or ', ' ').replace(' and ', ' ').replace('(', '').replace(')', '').split(" ") if selection in condition_list: continue # find all wildcards in condition found = False for wildcard_selection in wildcard_selections.findall(condition): # wildcard matches selection if re.search(wildcard_selection.replace(r"*", r".*"), selection) is not None: found = True break # selection was not found in condition if not found: print( Fore.RED + "Rule {} has an unused selection '{}'".format(file, selection)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with unused selections") # def test_field_name_typo(self): # # add "OriginalFilename" after Aurora switched to SourceFilename # # add "ProviderName" after special case powershell classic is resolved # faulty_rules = [] # for file in self.yield_next_rule_file_path(self.path_to_rules): # # typos is a list of tuples where each tuple contains ("The typo", "The correct version") # typos = [("ServiceFilename", "ServiceFileName"), ("TargetFileName", "TargetFilename"), ("SourceFileName", "OriginalFileName"), ("Commandline", "CommandLine"), ("Targetobject", "TargetObject"), ("OriginalName", "OriginalFileName"), ("ImageFileName", "OriginalFileName"), ("details", "Details")] # # Some fields exists in certain log sources in different forms than other log sources. We need to handle these as special cases # # We check first the logsource to handle special cases # logsource = self.get_rule_part(file_path=file, part_name="logsource").values() # # add more typos in specific logsources below # if "windefend" in logsource: # typos += [("New_Value", "NewValue"), ("Old_Value", "OldValue"), ('Source_Name', 'SourceName'), ("Newvalue", "NewValue"), ("Oldvalue", "OldValue"), ('Sourcename', 'SourceName')] # elif "registry_set" in logsource or "registry_add" in logsource or "registry_event" in logsource: # typos += [("Targetobject", "TargetObject"), ("Eventtype", "EventType"), ("Newname", "NewName")] # elif "process_creation" in logsource: # typos += [("Parentimage", "ParentImage"), ("Integritylevel", "IntegrityLevel"), ("IntegritiLevel", "IntegrityLevel")] # elif "file_access" in logsource: # del(typos[typos.index(("TargetFileName", "TargetFilename"))]) # We remove the entry to "TargetFileName" to avoid confusion # typos += [("TargetFileName", "FileName"), ("TargetFilename","FileName")] # detection = self.get_rule_part(file_path=file, part_name="detection") # if detection: # for search_identifier in detection: # if isinstance(detection[search_identifier], dict): # for field in detection[search_identifier]: # for typo in typos: # if typo[0] in field: # print(Fore.RED + "Rule {} has a common typo ({}) which should be ({}) in selection ({}/{})".format(file, typo[0], typo[1], search_identifier, field)) # faulty_rules.append(file) # self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with common typos in field names.") def test_unknown_value_modifier(self): known_modifiers = ["contains", "startswith", "endswith", "all", "base64offset", "base64", "utf16le", "utf16be", "wide", "utf16", "windash", "re"] faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part(file_path=file, part_name="detection") if detection: for search_identifier in detection: if isinstance(detection[search_identifier], dict): for field in detection[search_identifier]: if "|" in field: for current_modifier in field.split('|')[1:]: found = False for target_modifier in known_modifiers: if current_modifier == target_modifier: found = True if not found: print(Fore.RED + "Rule {} uses an unknown field modifier ({}/{})".format(file, search_identifier, field)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with unknown value modifiers. Most often it is just a typo.") def test_all_value_modifier_single_item(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") if detection: for search_identifier in detection: if isinstance(detection[search_identifier], dict): for field in detection[search_identifier]: if "|all" in field and not isinstance(detection[search_identifier][field], list): print(Fore.RED + "Rule {} uses the 'all' modifier on a single item in selection ({}/{})".format( file, search_identifier, field)) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules with |all modifier only having one item. " + "Single item values are not allowed to have an all modifier as some back-ends cannot support it. " + "If you use it as a workaround to duplicate a field in a selection, use a new selection instead.") def test_field_user_localization(self): def checkUser(faulty_rules, dict): for key, value in dict.items(): if "User" in key: if type(value) == str: if "AUTORI" in value or "AUTHORI" in value: print("Localized user name '{}'.".format(value)) faulty_rules.append(file) faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") for sel_key, sel_value in detection.items(): if sel_key == "condition" or sel_key == "timeframe": continue # single item selection if type(sel_value) == dict: checkUser(faulty_rules, sel_value) if type(sel_value) == list: # skip keyword selection if type(sel_value[0]) != dict: continue # multiple item selection for item in sel_value: checkUser(faulty_rules, item) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules that match using localized user accounts. Better employ a generic version such as:\n" + "User|contains: # covers many language settings\n" + " - 'AUTHORI'\n" + " - 'AUTORI'") def test_condition_operator_casesensitive(self): faulty_rules = [] for file in self.yield_next_rule_file_path(self.path_to_rules): detection = self.get_rule_part( file_path=file, part_name="detection") if detection: valid = True if isinstance(detection["condition"], str): param = detection["condition"].split(' ') for item in param: if item.lower() == 'or' and not item == 'or': valid = False elif item.lower() == 'and' and not item == 'and': valid = False elif item.lower() == 'not' and not item == 'not': valid = False elif item.lower() == 'of' and not item == 'of': valid = False if not valid: print(Fore.RED + "Rule {} has a invalid condition '{}' : 'or','and','not','of' are lowercase".format( file, detection["condition"])) faulty_rules.append(file) self.assertEqual(faulty_rules, [], Fore.RED + "There are rules using condition without lowercase operator") def get_mitre_data(): """ Use Tags from CTI subrepo to get consitant data """ cti_path = "tests/cti/" # Get ATT&CK information lift = attack_client(local_path=cti_path) # Techniques MITRE_TECHNIQUES = [] MITRE_TECHNIQUE_NAMES = [] MITRE_PHASE_NAMES = set() MITRE_TOOLS = [] MITRE_GROUPS = [] # Techniques enterprise_techniques = lift.get_enterprise_techniques() for t in enterprise_techniques: MITRE_TECHNIQUE_NAMES.append( t['name'].lower().replace(' ', '_').replace('-', '_')) for r in t.external_references: if 'external_id' in r: MITRE_TECHNIQUES.append(r['external_id'].lower()) if 'kill_chain_phases' in t: for kc in t['kill_chain_phases']: if 'phase_name' in kc: MITRE_PHASE_NAMES.add(kc['phase_name'].replace('-', '_')) # Tools / Malware enterprise_tools = lift.get_enterprise_tools() for t in enterprise_tools: for r in t.external_references: if 'external_id' in r: MITRE_TOOLS.append(r['external_id'].lower()) enterprise_malware = lift.get_enterprise_malware() for m in enterprise_malware: for r in m.external_references: if 'external_id' in r: MITRE_TOOLS.append(r['external_id'].lower()) # Groups enterprise_groups = lift.get_enterprise_groups() for g in enterprise_groups: for r in g.external_references: if 'external_id' in r: MITRE_GROUPS.append(r['external_id'].lower()) # Debugging print("MITRE ATT&CK LIST LENGTHS: %d %d %d %d %d" % (len(MITRE_TECHNIQUES), len( MITRE_TECHNIQUE_NAMES), len(list(MITRE_PHASE_NAMES)), len(MITRE_GROUPS), len(MITRE_TOOLS))) # Combine all IDs to a big tag list return ["attack." + item for item in MITRE_TECHNIQUES + MITRE_TECHNIQUE_NAMES + list(MITRE_PHASE_NAMES) + MITRE_GROUPS + MITRE_TOOLS] if __name__ == "__main__": init(autoreset=True) # Run the tests unittest.main()