misp-modules/misp_modules/modules/expansion/stix2_pattern_syntax_validator.py

import json
try:
    from stix2patterns.validator import run_validator
except ImportError:
    print("stix2 patterns python library is missing, use 'pip3 install stix2-patterns' to install it.")

misperrors = {'error': 'Error'}
mispattributes = {'input': ['stix2-pattern'], 'output': ['text']}
moduleinfo = {
    'version': '0.1',
    'author': 'Christian Studer',
    'module-type': ['hover'],
    'name': 'STIX2 Pattern Syntax Validator',
    'description': 'An expansion hover module to perform a syntax check on stix2 patterns.',
    'logo': 'stix.png',
    'requirements': ['stix2patterns python library'],
    'features': 'This module takes a STIX2 pattern attribute as input and performs a syntax check on it.\n\nIt displays then that the rule is valid if it is the case, and the error related to the rule otherwise.',
    'references': ['[STIX2.0 patterning specifications](http://docs.oasis-open.org/cti/stix/v2.0/cs01/part5-stix-patterning/stix-v2.0-cs01-part5-stix-patterning.html)'],
    'input': 'A STIX2 pattern attribute.',
    'output': 'Text describing the validity of the STIX2 pattern.',
}
moduleconfig = []


def handler(q=False):
    if q is False:
        return False
    request = json.loads(q)
    if not request.get('stix2-pattern'):
        misperrors['error'] = 'STIX2 pattern missing'
        return misperrors
    pattern = request.get('stix2-pattern')
    syntax_errors = []
    for p in pattern[1:-1].split(' AND '):
        syntax_validator = run_validator("[{}]".format(p))
        if syntax_validator:
            for error in syntax_validator:
                syntax_errors.append(error)
    if syntax_errors:
        s = 's' if len(syntax_errors) > 1 else ''
        s_errors = ""
        for error in syntax_errors:
            s_errors += "{}\n".format(error[6:])
        result = "Syntax error{}: \n{}".format(s, s_errors[:-1])
    else:
        result = "Syntax valid"
    return {'results': [{'types': mispattributes['output'], 'values': result}]}


def introspection():
    return mispattributes


def version():
    moduleinfo['config'] = moduleconfig
    return moduleinfo