cti-python-stix2/stix2/test/test_stix2.py

"""Tests for the stix2 library"""

import datetime

import pytest
import pytz

import stix2

amsterdam = pytz.timezone('Europe/Amsterdam')
eastern = pytz.timezone('US/Eastern')


@pytest.mark.parametrize('dt,timestamp', [
    (datetime.datetime(2017, 1, 1, tzinfo=pytz.utc), '2017-01-01T00:00:00Z'),
    (amsterdam.localize(datetime.datetime(2017, 1, 1)), '2016-12-31T23:00:00Z'),
    (eastern.localize(datetime.datetime(2017, 1, 1, 12, 34, 56)), '2017-01-01T17:34:56Z'),
    (eastern.localize(datetime.datetime(2017, 7, 1)), '2017-07-01T04:00:00Z'),
])
def test_timestamp_formatting(dt, timestamp):
    assert stix2.format_datetime(dt) == timestamp


INDICATOR_ID = "indicator--01234567-89ab-cdef-0123-456789abcdef"
MALWARE_ID = "malware--fedcba98-7654-3210-fedc-ba9876543210"
RELATIONSHIP_ID = "relationship--00000000-1111-2222-3333-444444444444"

# Minimum required args for an Indicator instance
INDICATOR_KWARGS = dict(
    labels=['malicious-activity'],
    pattern="[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']",
)

# Minimum required args for a Malware instance
MALWARE_KWARGS = dict(
    labels=['ransomware'],
    name="Cryptolocker",
)


# Minimum required args for a Relationship instance
RELATIONSHIP_KWARGS = dict(
    relationship_type="indicates",
    source_ref=INDICATOR_ID,
    target_ref=MALWARE_ID,
)


@pytest.fixture
def indicator():
    return stix2.Indicator(id=INDICATOR_ID, **INDICATOR_KWARGS)


@pytest.fixture
def malware():
    return stix2.Malware(id=MALWARE_ID, **MALWARE_KWARGS)


@pytest.fixture
def relationship():
    return stix2.Relationship(**RELATIONSHIP_KWARGS)


EXPECTED_INDICATOR = """{
    "created": "2017-01-01T00:00:00Z",
    "id": "indicator--01234567-89ab-cdef-0123-456789abcdef",
    "labels": [
        "malicious-activity"
    ],
    "modified": "2017-01-01T00:00:00Z",
    "pattern": "[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']",
    "type": "indicator",
    "valid_from": "1970-01-01T00:00:00Z"
}"""


def test_indicator_with_all_required_fields():
    now = datetime.datetime(2017, 1, 1, 0, 0, 0, tzinfo=pytz.utc)
    epoch = datetime.datetime(1970, 1, 1, 0, 0, 0, tzinfo=pytz.utc)

    indicator = stix2.Indicator(
        type="indicator",
        id=INDICATOR_ID,
        labels=['malicious-activity'],
        pattern="[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']",
        created=now,
        modified=now,
        valid_from=epoch,
    )

    assert str(indicator) == EXPECTED_INDICATOR


def test_indicator_autogenerated_fields(indicator):
    assert indicator.type == 'indicator'
    assert indicator.id.startswith('indicator--')
    assert indicator.created is not None
    assert indicator.modified is not None
    assert indicator.labels == ['malicious-activity']
    assert indicator.pattern == "[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']"
    assert indicator.valid_from is not None

    assert indicator['type'] == 'indicator'
    assert indicator['id'].startswith('indicator--')
    assert indicator['created'] is not None
    assert indicator['modified'] is not None
    assert indicator['labels'] == ['malicious-activity']
    assert indicator['pattern'] == "[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']"
    assert indicator['valid_from'] is not None


def test_indicator_type_must_be_indicator():
    with pytest.raises(ValueError) as excinfo:
        indicator = stix2.Indicator(type='xxx')

    assert "Indicator must have type='indicator'." in str(excinfo)


def test_indicator_id_must_start_with_indicator():
    with pytest.raises(ValueError) as excinfo:
        indicator = stix2.Indicator(id='my-prefix--')

    assert "Indicator id values must begin with 'indicator--'." in str(excinfo)


def test_indicator_required_field_labels():
    with pytest.raises(ValueError) as excinfo:
        indicator = stix2.Indicator()
    assert "Missing required field for Indicator: 'labels'." in str(excinfo)


def test_indicator_required_field_pattern():
    with pytest.raises(ValueError) as excinfo:
        # Label is checked first, so make sure that is provided
        indicator = stix2.Indicator(labels=['malicious-activity'])
    assert "Missing required field for Indicator: 'pattern'." in str(excinfo)


def test_cannot_assign_to_indicator_attributes(indicator):
    with pytest.raises(ValueError) as excinfo:
        indicator.valid_from = datetime.datetime.now()

    assert "Cannot modify properties after creation." in str(excinfo)


def test_invalid_kwarg_to_indicator():
    with pytest.raises(TypeError) as excinfo:
        indicator = stix2.Indicator(my_custom_property="foo", **INDICATOR_KWARGS)
    assert "unexpected keyword arguments: ['my_custom_property']" in str(excinfo)


EXPECTED_MALWARE = """{
    "created": "2016-05-12T08:17:27Z",
    "id": "malware--fedcba98-7654-3210-fedc-ba9876543210",
    "labels": [
        "ransomware"
    ],
    "modified": "2016-05-12T08:17:27Z",
    "name": "Cryptolocker",
    "type": "malware"
}"""


def test_malware_with_all_required_fields():
    now = datetime.datetime(2016, 5, 12, 8, 17, 27, tzinfo=pytz.utc)

    malware = stix2.Malware(
        type="malware",
        id=MALWARE_ID,
        created=now,
        modified=now,
        labels=["ransomware"],
        name="Cryptolocker",
    )

    assert str(malware) == EXPECTED_MALWARE


def test_malware_autogenerated_fields(malware):
    assert malware.type == 'malware'
    assert malware.id.startswith('malware--')
    assert malware.created is not None
    assert malware.modified is not None
    assert malware.labels == ['ransomware']
    assert malware.name == "Cryptolocker"

    assert malware['type'] == 'malware'
    assert malware['id'].startswith('malware--')
    assert malware['created'] is not None
    assert malware['modified'] is not None
    assert malware['labels'] == ['ransomware']
    assert malware['name'] == "Cryptolocker"


def test_malware_type_must_be_malware():
    with pytest.raises(ValueError) as excinfo:
        malware = stix2.Malware(type='xxx')

    assert "Malware must have type='malware'." in str(excinfo)


def test_malware_id_must_start_with_malware():
    with pytest.raises(ValueError) as excinfo:
        malware = stix2.Malware(id='my-prefix--')

    assert "Malware id values must begin with 'malware--'." in str(excinfo)


def test_malware_required_field_labels():
    with pytest.raises(ValueError) as excinfo:
        malware = stix2.Malware()
    assert "Missing required field for Malware: 'labels'." in str(excinfo)


def test_malware_required_field_name():
    with pytest.raises(ValueError) as excinfo:
        # Label is checked first, so make sure that is provided
        malware = stix2.Malware(labels=['ransomware'])
    assert "Missing required field for Malware: 'name'." in str(excinfo)


def test_cannot_assign_to_malware_attributes(malware):
    with pytest.raises(ValueError) as excinfo:
        malware.name = "Cryptolocker II"

    assert "Cannot modify properties after creation." in str(excinfo)


def test_invalid_kwarg_to_malware():
    with pytest.raises(TypeError) as excinfo:
        malware = stix2.Malware(my_custom_property="foo", **MALWARE_KWARGS)
    assert "unexpected keyword arguments: ['my_custom_property']" in str(excinfo)


EXPECTED_RELATIONSHIP = """{
    "created": "2016-04-06T20:06:37Z",
    "id": "relationship--00000000-1111-2222-3333-444444444444",
    "modified": "2016-04-06T20:06:37Z",
    "relationship_type": "indicates",
    "source_ref": "indicator--01234567-89ab-cdef-0123-456789abcdef",
    "target_ref": "malware--fedcba98-7654-3210-fedc-ba9876543210",
    "type": "relationship"
}"""


def test_relationship_all_required_fields():
    now = datetime.datetime(2016, 4, 6, 20, 6, 37, tzinfo=pytz.utc)

    relationship = stix2.Relationship(
        type='relationship',
        id=RELATIONSHIP_ID,
        created=now,
        modified=now,
        relationship_type='indicates',
        source_ref=INDICATOR_ID,
        target_ref=MALWARE_ID,
    )
    assert str(relationship) == EXPECTED_RELATIONSHIP


def test_relationship_autogenerated_fields(relationship):
    assert relationship.type == 'relationship'
    assert relationship.id.startswith('relationship--')
    assert relationship.created is not None
    assert relationship.modified is not None
    assert relationship.relationship_type == 'indicates'
    assert relationship.source_ref == INDICATOR_ID
    assert relationship.target_ref == MALWARE_ID

    assert relationship['type'] == 'relationship'
    assert relationship['id'].startswith('relationship--')
    assert relationship['created'] is not None
    assert relationship['modified'] is not None
    assert relationship['relationship_type'] == 'indicates'
    assert relationship['source_ref'] == INDICATOR_ID
    assert relationship['target_ref'] == MALWARE_ID


def test_relationship_type_must_be_relationship():
    with pytest.raises(ValueError) as excinfo:
        relationship = stix2.Relationship(type='xxx')

    assert "Relationship must have type='relationship'." in str(excinfo)


def test_relationship_id_must_start_with_relationship():
    with pytest.raises(ValueError) as excinfo:
        relationship = stix2.Relationship(id='my-prefix--')

    assert "Relationship id values must begin with 'relationship--'." in str(excinfo)


def test_relationship_required_field_relationship_type():
    with pytest.raises(ValueError) as excinfo:
        relationship = stix2.Relationship()
    assert "Missing required field for Relationship: 'relationship_type'." in str(excinfo)


def test_relationship_required_field_source_ref():
    with pytest.raises(ValueError) as excinfo:
        # relationship_type is checked first, so make sure that is provided
        relationship = stix2.Relationship(relationship_type='indicates')
    assert "Missing required field for Relationship: 'source_ref'." in str(excinfo)


def test_relationship_required_field_target_ref():
    with pytest.raises(ValueError) as excinfo:
        # relationship_type and source_ref are checked first, so make sure those are provided
        relationship = stix2.Relationship(
            relationship_type='indicates',
            source_ref=INDICATOR_ID
        )
    assert "Missing required field for Relationship: 'target_ref'." in str(excinfo)


def test_cannot_assign_to_relationship_attributes(relationship):
    with pytest.raises(ValueError) as excinfo:
        relationship.relationship_type = "derived-from"

    assert "Cannot modify properties after creation." in str(excinfo)


def test_invalid_kwarg_to_relationship():
    with pytest.raises(TypeError) as excinfo:
        relationship = stix2.Relationship(my_custom_property="foo", **RELATIONSHIP_KWARGS)
    assert "unexpected keyword arguments: ['my_custom_property']" in str(excinfo)


def test_create_relationship_from_objects_rather_than_ids(indicator, malware):
    relationship = stix2.Relationship(
        relationship_type="indicates",
        source_ref=indicator,
        target_ref=malware,
    )

    assert relationship.relationship_type == 'indicates'
    assert relationship.source_ref == INDICATOR_ID
    assert relationship.target_ref == MALWARE_ID