new: First version of a yara rule creation expansion module

misp_modules/modules/expansion/__init__.py

@@ -1,3 +1,3 @@
 from . import _vmray
 
-__all__ = ['vmray_submit', 'asn_history', 'circl_passivedns', 'circl_passivessl', 'countrycode', 'cve', 'dns', 'domaintools', 'eupi', 'farsight_passivedns', 'ipasn', 'passivetotal', 'sourcecache', 'virustotal', 'whois', 'shodan', 'reversedns', 'geoip_country', 'wiki', 'iprep', 'threatminer', 'otx', 'threatcrowd', 'vulndb', 'crowdstrike_falcon', 'yara_syntax_validator', 'hashdd', 'onyphe', 'onyphe_full', 'rbl', 'xforceexchange', 'sigma_syntax_validator', 'stix2_pattern_syntax_validator', 'sigma_queries', 'dbl_spamhaus', 'vulners']
+__all__ = ['vmray_submit', 'asn_history', 'circl_passivedns', 'circl_passivessl', 'countrycode', 'cve', 'dns', 'domaintools', 'eupi', 'farsight_passivedns', 'ipasn', 'passivetotal', 'sourcecache', 'virustotal', 'whois', 'shodan', 'reversedns', 'geoip_country', 'wiki', 'iprep', 'threatminer', 'otx', 'threatcrowd', 'vulndb', 'crowdstrike_falcon', 'yara_syntax_validator', 'hashdd', 'onyphe', 'onyphe_full', 'rbl', 'xforceexchange', 'sigma_syntax_validator', 'stix2_pattern_syntax_validator', 'sigma_queries', 'dbl_spamhaus', 'vulners', 'yara_query']

misp_modules/modules/expansion/yara_query.py

@@ -0,0 +1,44 @@
+import json
+import sys
+
+misperrors = {'error': 'Error'}
+moduleinfo = {'version': '1', 'author': 'Christian STUDER',
+              'description': 'Yara export for hashes.',
+              'module-type': ['expansion', 'hover'],
+              'require_standard_format': True}
+moduleconfig = []
+mispattributes = {'input': ['md5', 'sha1', 'sha256', 'filename|md5', 'filename|sha1', 'filename|sha256'], 'output': ['yara rule']}
+
+def hash_cond(hashtype, hashvalue):
+    condition = 'hash.{}(0, filesize) == {}'.format(hashtype, hashvalue.lower())
+    return condition, 'hash'
+
+def handler(q=False):
+    if q is False:
+        return False
+    request = json.loads(q)
+    del request['module']
+    if 'event_id' in request:
+        del request['event_id']
+    uuid = request.pop('attribute_uuid') if 'attribute_uuid' in request else None
+    rules = []
+    types = []
+    for attribute_type, value in request.items():
+        if 'filename' in attribute_type:
+            _, attribute_type = attribute_type.split('|')
+            _, value = value.split('|')
+        condition, required_module = hash_cond(attribute_type, value)
+        condition = '\r\n\t\t'.join([condition])
+        import_section = '\r\n'.join(['import "{}"'.format(required_module)])
+        rule_start = 'rule %s {' % uuid if uuid else 'rule {'
+        condition = '\tcondition:\r\n\t\t{}'.format(condition)
+        rules.append('\r\n'.join([rule_start, condition, '}']))
+        types.append('yara')
+    return {'results': [{'types': [t], 'values': [v]} for t, v in zip(types, rules)]}
+
+def introspection():
+    return mispattributes
+
+def version():
+    moduleinfo['config'] = moduleconfig
+    return moduleinfo