mirror of https://github.com/MISP/misp-modules
				
				
				
			
		
			
				
	
	
		
			226 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			226 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			Python
		
	
	
import json
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import pymisp
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from base64 import b64encode
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from collections import OrderedDict
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from . import check_input_attribute, checking_error, standard_error_message
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from pymisp import MISPAttribute, MISPEvent, MISPObject
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from trustar import TruStar, Indicator
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from urllib.parse import quote
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misperrors = {'error': "Error"}
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mispattributes = {
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    'input': ["btc", "domain", "email-src", "filename", "hostname", "ip-src", "ip-dst", "malware-type", "md5", "sha1",
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              "sha256", "url"], 'format': 'misp_standard'}
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moduleinfo = {'version': "0.1", 'author': "Jesse Hedden",
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              'description': "Enrich data with TruSTAR",
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              'module-type': ["hover", "expansion"]}
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moduleconfig = ["user_api_key", "user_api_secret", "enclave_ids"]
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MAX_PAGE_SIZE = 100  # Max allowable page size returned from /1.3/indicators/summaries endpoint
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class TruSTARParser:
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    ENTITY_TYPE_MAPPINGS = {
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        'BITCOIN_ADDRESS': "btc",
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        'CIDR_BLOCK': "ip-src",
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        'CVE': "vulnerability",
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        'URL': "url",
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        'EMAIL_ADDRESS': "email-src",
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        'SOFTWARE': "filename",
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        'IP': "ip-src",
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        'MALWARE': "malware-type",
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        'MD5': "md5",
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        'REGISTRY_KEY': "regkey",
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        'SHA1': "sha1",
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        'SHA256': "sha256"
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    }
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    # Relevant fields from each TruSTAR endpoint
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    SUMMARY_FIELDS = ["severityLevel", "source", "score", "attributes"]
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    METADATA_FIELDS = ["sightings", "firstSeen", "lastSeen", "tags"]
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    REPORT_BASE_URL = "https://station.trustar.co/constellation/reports/{}"
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    CLIENT_METATAG = f"MISP-{pymisp.__version__}"
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    def __init__(self, attribute, config):
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        config['enclave_ids'] = config.get('enclave_ids', "").strip().split(',')
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        config['client_metatag'] = self.CLIENT_METATAG
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        self.ts_client = TruStar(config=config)
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        self.misp_event = MISPEvent()
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        self.misp_attribute = MISPAttribute()
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        self.misp_attribute.from_dict(**attribute)
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        self.misp_event.add_attribute(**self.misp_attribute)
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    def get_results(self):
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        """
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        Returns the MISP Event enriched with TruSTAR indicator summary data.
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        """
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        try:
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            event = json.loads(self.misp_event.to_json())
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            results = {key: event[key] for key in ('Attribute', 'Object') if (key in event and event[key])}
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            return {'results': results}
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        except Exception as e:
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            misperrors['error'] += f" -- Encountered issue serializing enrichment data -- {e}"
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            return misperrors
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    def generate_trustar_link(self, entity_type, entity_value):
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        """
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        Generates link to TruSTAR report of entity.
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        :param entity_type: <str> Type of entity.
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        :param entity_value: <str> Value of entity.
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        :return: <str> Link to indicator report in TruSTAR platform.
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        """
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        report_id = b64encode(quote(f"{entity_type}|{entity_value}").encode()).decode()
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        return self.REPORT_BASE_URL.format(report_id)
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    @staticmethod
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    def extract_tags(enrichment_report):
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        """
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        Extracts tags from the enrichment report in order to add them
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        to the TruSTAR MISP Object. Removes tags from report to avoid
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        redundancy.
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        :param: <OrderedDict> Enrichment data.
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        :return: <list> List of tags.
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        """
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        if enrichment_report and enrichment_report.get('tags'):
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            return [tag.get('name') for tag in enrichment_report.pop('tags')]
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        return None
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    def generate_enrichment_report(self, summary, metadata):
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        """
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        Extracts desired fields from summary and metadata reports and
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        generates an enrichment report.
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        :param summary: <trustar.IndicatorSummary> Indicator summary report.
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        :param metadata: <trustar.Indicator> Indicator metadata report.
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        :return: <str> Enrichment report.
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        """
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        # Preserve order of fields as they exist in SUMMARY_FIELDS and METADATA_FIELDS
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        enrichment_report = OrderedDict()
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        if summary:
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            summary_dict = summary.to_dict()
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            enrichment_report.update(
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                {field: summary_dict[field] for field in self.SUMMARY_FIELDS if summary_dict.get(field)})
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        if metadata:
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            metadata_dict = metadata.to_dict()
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            enrichment_report.update(
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                {field: metadata_dict[field] for field in self.METADATA_FIELDS if metadata_dict.get(field)})
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        return enrichment_report
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    def parse_indicator_summary(self, indicator, summary, metadata):
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        """
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        Pulls enrichment data from the TruSTAR /indicators/summaries and /indicators/metadata endpoints
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        and creates a MISP trustar_report.
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        :param indicator: <str> Value of the attribute
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        :summary: <trustar.IndicatorSummary> Indicator summary response object.
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        :metadata: <trustar.Indicator> Indicator response object.
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        """
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        # Verify that the indicator type is supported by TruSTAR
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        if summary and summary.indicator_type in self.ENTITY_TYPE_MAPPINGS:
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            indicator_type = summary.indicator_type
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        elif metadata and metadata.type in self.ENTITY_TYPE_MAPPINGS:
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            indicator_type = metadata.type
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        else:
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            misperrors['error'] += " -- Attribute not found or not supported"
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            raise Exception
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        try:
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            # Extract most relevant fields from indicator summary and metadata responses
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            enrichment_report = self.generate_enrichment_report(summary, metadata)
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            tags = self.extract_tags(enrichment_report)
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            if enrichment_report:
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                # Create MISP trustar_report object and populate it with enrichment data
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                trustar_obj = MISPObject('trustar_report')
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                trustar_obj.add_attribute(indicator_type, attribute_type=self.ENTITY_TYPE_MAPPINGS[indicator_type],
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                                          value=indicator)
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                trustar_obj.add_attribute("INDICATOR_SUMMARY", attribute_type="text",
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                                          value=json.dumps(enrichment_report, indent=4))
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                report_link = self.generate_trustar_link(indicator_type, indicator)
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                trustar_obj.add_attribute("REPORT_LINK", attribute_type="link", value=report_link)
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                self.misp_event.add_object(**trustar_obj)
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            elif not tags:
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                # If enrichment report is empty and there are no tags, nothing to add to attribute
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                raise Exception("No relevant data found")
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            if tags:
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                for tag in tags:
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                    self.misp_event.add_attribute_tag(tag, indicator)
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        except Exception as e:
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            misperrors['error'] += f" -- Error enriching attribute {indicator} -- {e}"
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            raise e
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def handler(q=False):
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    """
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    MISP handler function. A user's API key and secret will be retrieved from the MISP
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    request and used to create a TruSTAR API client. If enclave IDs are provided, only
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    those enclaves will be queried for data. Otherwise, all of the enclaves a user has
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    access to will be queried.
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    """
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    if q is False:
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        return False
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    request = json.loads(q)
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    config = request.get('config', {})
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    if not config.get('user_api_key') or not config.get('user_api_secret'):
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        misperrors['error'] = "Your TruSTAR API key and secret are required for indicator enrichment."
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        return misperrors
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    if not request.get('attribute') or not check_input_attribute(request['attribute'], requirements=('type', 'value')):
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        return {'error': f'{standard_error_message}, {checking_error}.'}
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    attribute = request['attribute']
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    if attribute['type'] not in mispattributes['input']:
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        return {'error': 'Unsupported attribute type.'}
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    trustar_parser = TruSTARParser(attribute, config)
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    metadata = None
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    summary = None
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    try:
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        metadata = trustar_parser.ts_client.get_indicators_metadata([Indicator(value=attribute['value'])])[0]
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    except IndexError:
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        misperrors['error'] += f" -- No metadata found for indicator {attribute['value']}"
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    except Exception as e:
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        misperrors['error'] += f" -- Could not retrieve indicator metadata from TruSTAR {e}"
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    try:
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        summary = list(
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            trustar_parser.ts_client.get_indicator_summaries([attribute['value']], page_size=MAX_PAGE_SIZE))[0]
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    except IndexError:
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        misperrors['error'] += f" -- No summary data found for indicator {attribute['value']}"
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    except Exception as e:
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        misperrors['error'] += f" -- Unable to retrieve TruSTAR summary data: {e}"
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    try:
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        trustar_parser.parse_indicator_summary(attribute['value'], summary, metadata)
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    except Exception:
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        return misperrors
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    return trustar_parser.get_results()
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def introspection():
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    return mispattributes
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def version():
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    moduleinfo['config'] = moduleconfig
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    return moduleinfo
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