Source code for workbench.workers.yara_sigs

''' Yara worker '''
import os
import yara
import pprint
import collections

# We want to load this once per module load
def get_rules_from_disk():
[docs] ''' Recursively traverse the yara/rules directory for rules ''' # Try to find the yara rules directory relative to the worker my_dir = os.path.dirname(os.path.realpath(__file__)) yara_rule_path = os.path.join(my_dir, 'yara/rules') if not os.path.exists(yara_rule_path): raise RuntimeError('yara could not find yara rules directory under: %s' % my_dir) # Okay load in all the rules under the yara rule path rules = yara.load_rules(rules_rootpath=yara_rule_path, fast_match=True) return rules YARA_RULES = get_rules_from_disk()
class YaraSigs(object):
[docs] ''' This worker check for matches against yara sigs. Output keys: [matches:list of matches] ''' dependencies = ['sample'] def __init__(self): self.rules = YARA_RULES def execute(self, input_data):
[docs] ''' yara worker execute method ''' raw_bytes = input_data['sample']['raw_bytes'] matches = self.rules.match_data(raw_bytes) # The matches data is organized in the following way # {'filename1': [match_list], 'filename2': [match_list]} # match_list = list of match # match = {'meta':{'description':'blah}, tags=[], matches:True, # strings:[string_list]} # string = {'flags':blah, 'identifier':'$', 'data': FindWindow, 'offset'} # # So we're going to flatten a bit (shrug) # {filename_match_meta_description: string_list} flat_data = collections.defaultdict(list) for filename, match_list in matches.iteritems(): for match in match_list: if 'description' in match['meta']: new_tag = filename+'_'+match['meta']['description'] else: new_tag = filename+'_'+match['rule'] for match in match['strings']: flat_data[new_tag].append(match['data']) # Remove duplicates flat_data[new_tag] = list(set(flat_data[new_tag])) return {'matches': flat_data} # Unit test: Create the class, the proper input and run the execute() method for a test def test():
[docs] ''' Unit test''' # This worker test requires a local server running import zerorpc workbench = zerorpc.Client(timeout=300, heartbeat=60) workbench.connect("tcp://") # Test a file with known yara sigs data_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), '../data/pe/bad/auriga.exe') with open(data_path,'rb') as pe_file: base_name = os.path.basename(data_path) md5 = workbench.store_sample(, base_name, 'exe') # Grab the sample from workbench input_data = workbench.get_sample(md5) # Execute the worker (unit test) worker = YaraSigs() output = worker.execute(input_data) print '\n<<< Unit Test >>>' pprint.pprint(output) # Execute the worker (server test) output = workbench.work_request('yara_sigs', md5) print '\n<<< Server Test >>>' pprint.pprint(output) if __name__ == "__main__":