Exemplo n.º 1
0
def to_cybox_observable(obj, exclude=None, bin_fmt="raw"):
    """
    Convert a CRITs TLO to a CybOX Observable.

    :param obj: The TLO to convert.
    :type obj: :class:`crits.core.crits_mongoengine.CRITsBaseAttributes`
    :param exclude: Attributes to exclude.
    :type exclude: list
    :param bin_fmt: The format for the binary (if applicable).
    :type bin_fmt: str
    """

    type_ = obj._meta['crits_type']
    if type_ == 'Certificate':
        custom_prop = Property() # make a custom property so CRITs import can identify Certificate exports
        custom_prop.name = "crits_type"
        custom_prop.description = "Indicates the CRITs type of the object this CybOX object represents"
        custom_prop._value = "Certificate"
        obje = File() # represent cert information as file
        obje.md5 = obj.md5
        obje.file_name = obj.filename
        obje.file_format = obj.filetype
        obje.size_in_bytes = obj.size
        obje.custom_properties = CustomProperties()
        obje.custom_properties.append(custom_prop)
        obs = Observable(obje)
        obs.description = obj.description
        data = obj.filedata.read()
        if data: # if cert data available
            a = Artifact(data, Artifact.TYPE_FILE) # create artifact w/data
            a.packaging.append(Base64Encoding())
            obje.add_related(a, "Child_Of") # relate artifact to file

        return ([obs], obj.releasability)
    elif type_ == 'Domain':
        obje = DomainName()
        obje.value = obj.domain
        obje.type_ = obj.record_type

        return ([Observable(obje)], obj.releasability)
    elif type_ == 'Email':
        if exclude == None:
            exclude = []

        observables = []

        obje = EmailMessage()
        # Assume there is going to be at least one header
        obje.header = EmailHeader()

        if 'message_id' not in exclude:
            obje.header.message_id = String(obj.message_id)

        if 'subject' not in exclude:
            obje.header.subject = String(obj.subject)

        if 'sender' not in exclude:
            obje.header.sender = Address(obj.sender, Address.CAT_EMAIL)

        if 'reply_to' not in exclude:
            obje.header.reply_to = Address(obj.reply_to, Address.CAT_EMAIL)

        if 'x_originating_ip' not in exclude:
            obje.header.x_originating_ip = Address(obj.x_originating_ip,
                                                  Address.CAT_IPV4)

        if 'x_mailer' not in exclude:
            obje.header.x_mailer = String(obj.x_mailer)

        if 'boundary' not in exclude:
            obje.header.boundary = String(obj.boundary)

        if 'raw_body' not in exclude:
            obje.raw_body = obj.raw_body

        if 'raw_header' not in exclude:
            obje.raw_header = obj.raw_header

        #adding rest of email fields
        obje.header.cc = EmailRecipients(obj.cc)
        obje.header.to = EmailRecipients(obj.to)

        #copy fields where the names differ between objects
        if 'helo' not in exclude and 'email_server' not in exclude:
            obje.email_server = String(obj.helo)
        if ('from_' not in exclude and 'from' not in exclude and
            'from_address' not in exclude):
            obje.header.from_ = EmailAddress(obj.from_address)
        if 'date' not in exclude and 'isodate' not in exclude:
            obje.header.date = DateTime(obj.isodate)

        obje.attachments = Attachments()

        observables.append(Observable(obje))

        return (observables, obj.releasability)
    elif type_ == 'Indicator':
        observables = []
        obje = make_cybox_object(obj.ind_type, obj.value)
        observables.append(Observable(obje))

        return (observables, obj.releasability)
    elif type_ == 'IP':
        obje = Address()
        obje.address_value = obj.ip
        if obj.ip_type == IPTypes.IPV4_ADDRESS:
            obje.category = "ipv4-addr"
        elif obj.ip_type == IPTypes.IPV6_ADDRESS:
            obje.category = "ipv6-addr"
        elif obj.ip_type == IPTypes.IPV4_SUBNET:
            obje.category = "ipv4-net"
        elif obj.ip_type == IPTypes.IPV6_SUBNET:
            obje.category = "ipv6-subnet"

        return ([Observable(obje)], obj.releasability)
    elif type_ == 'PCAP':
        obje = File()
        obje.md5 = obj.md5
        obje.file_name = obj.filename
        obje.file_format = obj.contentType
        obje.size_in_bytes = obj.length
        obs = Observable(obje)
        obs.description = obj.description
        art = Artifact(obj.filedata.read(), Artifact.TYPE_NETWORK)
        art.packaging.append(Base64Encoding())
        obje.add_related(art, "Child_Of") # relate artifact to file

        return ([obs], obj.releasability)
    elif type_ == 'RawData':
        obje = Artifact(obj.data.encode('utf-8'), Artifact.TYPE_FILE)
        obje.packaging.append(Base64Encoding())
        obs = Observable(obje)
        obs.description = obj.description

        return ([obs], obj.releasability)
    elif type_ == 'Sample':
        if exclude == None:
            exclude = []

        observables = []
        f = File()
        for attr in ['md5', 'sha1', 'sha256', 'source']:
            if attr not in exclude:
                val = getattr(obj, attr, None)
                if val:
                    setattr(f, attr, val)
        if obj.ssdeep and 'ssdeep' not in exclude:
            f.add_hash(Hash(obj.ssdeep, Hash.TYPE_SSDEEP))
        if 'size' not in exclude and 'size_in_bytes' not in exclude:
            f.size_in_bytes = UnsignedLong(obj.size)
        if 'filename' not in exclude and 'file_name' not in exclude:
            f.file_name = obj.filename
        # create an Artifact object for the binary if it exists
        if 'filedata' not in exclude and bin_fmt:
            data = obj.filedata.read()
            if data: # if sample data available
                a = Artifact(data, Artifact.TYPE_FILE) # create artifact w/data
                if bin_fmt == "zlib":
                    a.packaging.append(ZlibCompression())
                    a.packaging.append(Base64Encoding())
                elif bin_fmt == "base64":
                    a.packaging.append(Base64Encoding())
                f.add_related(a, "Child_Of") # relate artifact to file
        if 'filetype' not in exclude and 'file_format' not in exclude:
            #NOTE: this doesn't work because the CybOX File object does not
            #   have any support built in for setting the filetype to a
            #   CybOX-binding friendly object (e.g., calling .to_dict() on
            #   the resulting CybOX object fails on this field.
            f.file_format = obj.filetype

        f.extracted_features = ExtractedFeatures()
        f.extracted_features.strings = ExtractedStrings()
        for name in obj.filenames:
            f.extracted_features.strings.append(ExtractedString(name))

        observables.append(Observable(f))
        return (observables, obj.releasability)
    else:
        return (None, None)