from impacket.ldap import ldapasn1 as ldapasn1_impacket
from impacket.ldap import ldap as ldap_impacket
import re

class CMEModule:
    '''
        Get description of users
        Module by @nodauf
    '''
    name = 'get-desc-users'
    description = 'Get description of the users. May contained password'
    supported_protocols = ['ldap']
    opsec_safe= True #Does the module touch disk?
    multiple_hosts = True #Does it make sense to run this module on multiple hosts at a time?

    def options(self, context, module_options):
        '''
            FILTER    Apply the FILTER (grep-like) (default: '')
            PASSWORDPOLICY    Is the windows password policy enabled ? (default: False)
            MINLENGTH    Minimum password length to match, only used if PASSWORDPOLICY is True (default: 6)
        '''
        self.FILTER = ''
        self.MINLENGTH = '6'
        self.PASSWORDPOLICY = False
        if 'FILTER' in module_options:
            self.FILTER = module_options['FILTER']
        if 'MINLENGTH' in module_options:
            self.MINLENGTH = module_options['MINLENGTH']
        if 'PASSWORDPOLICY' in module_options:
            self.PASSWORDPOLICY = True
            self.regex = re.compile("((?=[^ ]*[A-Z])(?=[^ ]*[a-z])(?=[^ ]*\d)|(?=[^ ]*[a-z])(?=[^ ]*\d)(?=[^ ]*[^\w \n])|(?=[^ ]*[A-Z])(?=[^ ]*\d)(?=[^ ]*[^\w \n])|(?=[^ ]*[A-Z])(?=[^ ]*[a-z])(?=[^ ]*[^\w \n]))[^ \n]{"+self.MINLENGTH+",}") # Credit : https://stackoverflow.com/questions/31191248/regex-password-must-have-at-least-3-of-the-4-of-the-following

    def on_login(self, context, connection):
        '''Concurrent. Required if on_admin_login is not present. This gets called on each authenticated connection'''
        # Building the search filter
        searchFilter = "(objectclass=user)"

        try:
            context.log.debug('Search Filter=%s' % searchFilter)
            resp = connection.ldapConnection.search(searchFilter=searchFilter,
                                        attributes=['sAMAccountName','description'],
                                        sizeLimit=0)
        except ldap_impacket.LDAPSearchError as e:
            if e.getErrorString().find('sizeLimitExceeded') >= 0:
                context.log.debug('sizeLimitExceeded exception caught, giving up and processing the data received')
                # We reached the sizeLimit, process the answers we have already and that's it. Until we implement
                # paged queries
                resp = e.getAnswers()
                pass
            else:
                logging.debug(e)
                return False

        answers = []
        context.log.debug('Total of records returned %d' % len(resp))
        for item in resp:
            if isinstance(item, ldapasn1_impacket.SearchResultEntry) is not True:
                continue
            sAMAccountName =  ''
            description = ''
            try:
                for attribute in item['attributes']:
                    if str(attribute['type']) == 'sAMAccountName':
                        sAMAccountName = str(attribute['vals'][0])
                    elif str(attribute['type']) == 'description':
                        description = attribute['vals'][0]
                if sAMAccountName != '' and description != '':
                    answers.append([sAMAccountName,description])
            except Exception as e:
                context.log.debug("Exception:", exc_info=True)
                context.log.debug('Skipping item, cannot process due to error %s' % str(e))
                pass
        answers = self.filter_answer(context, answers)
        if len(answers) > 0:
            context.log.success('Found following users: ')
            for answer in answers:
                context.log.highlight(u'User: {} description: {}'.format(answer[0],answer[1]))

    def filter_answer(self, context, answers):
        # No option to filter
        if self.FILTER == '' and not self.PASSWORDPOLICY:
            context.log.debug("No filter option enabled")
            return answers
        answersFiltered = []
        context.log.debug("Prepare to filter")
        if len(answers) > 0:
            for answer in answers:
                conditionFilter = False
                description = str(answer[1])
                # Filter
                if self.FILTER != '':
                    conditionFilter = False
                    if self.FILTER in description:
                        conditionFilter = True
    
                # Password policy
                if self.PASSWORDPOLICY:
                    conditionPasswordPolicy = False
                    if self.regex.search(description):
                        conditionPasswordPolicy = True
                
                if (self.FILTER and conditionFilter and self.PASSWORDPOLICY and conditionPasswordPolicy):
                    answersFiltered.append([answer[0],description])
                elif not self.FILTER and self.PASSWORDPOLICY and conditionPasswordPolicy:
                    answersFiltered.append([answer[0],description])
                elif not self.PASSWORDPOLICY and self.FILTER and conditionFilter:
                    answersFiltered.append([answer[0],description])
        return answersFiltered