From d1308f9924d67a04df11ca9841517feda808be8f Mon Sep 17 00:00:00 2001 From: chrisr3d Date: Fri, 2 Nov 2018 21:35:02 +0100 Subject: [PATCH] chg: Validating yara rules after their creation --- misp_modules/modules/expansion/yara_query.py | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/misp_modules/modules/expansion/yara_query.py b/misp_modules/modules/expansion/yara_query.py index a071bb4..565030c 100644 --- a/misp_modules/modules/expansion/yara_query.py +++ b/misp_modules/modules/expansion/yara_query.py @@ -1,5 +1,9 @@ import json import re +try: + import yara +except (OSError, ImportError): + print("yara is missing, use 'pip3 install yara' to install it.") misperrors = {'error': 'Error'} moduleinfo = {'version': '1', 'author': 'Christian STUDER', @@ -30,7 +34,12 @@ def handler(q=False): rule_start = 'import "hash" \r\nrule %s_%s {' % (attribute_type.upper(), re.sub(r'\W+', '_', uuid)) if uuid else 'import "hash"\r\nrule %s {' % attribute_type.upper() condition = '\tcondition:\r\n\t\t{}'.format(condition) rule = '\r\n'.join([rule_start, condition, '}']) - return {'results': [{'types': mispattributes['output'], 'values': [rule]}]} + try: + yara.compile(source=rule) + except Exception as e: + misperrors['error'] = 'Syntax error: {}'.format(e) + return misperrors + return {'results': [{'types': mispattributes['output'], 'values': rule}]} def introspection(): return mispattributes