# Copyright 2023 Google LLC # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import textwrap from pathlib import Path import fixtures import capa.main import capa.rules import capa.helpers import capa.features.file import capa.features.insn import capa.features.common import capa.features.freeze import capa.features.basicblock import capa.features.extractors.null import capa.features.extractors.base_extractor from capa.features.address import Address, AbsoluteVirtualAddress from capa.features.extractors.base_extractor import ( SampleHashes, ThreadHandle, ProcessHandle, ThreadAddress, ProcessAddress, DynamicCallAddress, DynamicFeatureExtractor, ) EXTRACTOR = capa.features.extractors.null.NullDynamicFeatureExtractor( base_address=AbsoluteVirtualAddress(0x401000), sample_hashes=SampleHashes( md5="6eb7ee7babf913d75df3f86c229df9e7", sha1="2a082494519acd5130d5120fa48786df7275fdd7", sha256="0c7d1a34eb9fd55bedbf37ba16e3d5dd8c1dd1d002479cc4af27ef0f82bb4792", ), global_features=[], file_features=[ (AbsoluteVirtualAddress(0x402345), capa.features.common.Characteristic("embedded pe")), ], processes={ ProcessAddress(pid=1): capa.features.extractors.null.ProcessFeatures( name="explorer.exe", features=[], threads={ ThreadAddress(ProcessAddress(pid=1), tid=1): capa.features.extractors.null.ThreadFeatures( features=[], calls={ DynamicCallAddress( thread=ThreadAddress(ProcessAddress(pid=1), tid=1), id=1 ): capa.features.extractors.null.CallFeatures( name="CreateFile(12)", features=[ ( DynamicCallAddress(thread=ThreadAddress(ProcessAddress(pid=1), tid=1), id=1), capa.features.insn.API("CreateFile"), ), ( DynamicCallAddress(thread=ThreadAddress(ProcessAddress(pid=1), tid=1), id=1), capa.features.insn.Number(12), ), ], ), DynamicCallAddress( thread=ThreadAddress(ProcessAddress(pid=1), tid=1), id=2 ): capa.features.extractors.null.CallFeatures( name="WriteFile()", features=[ ( DynamicCallAddress(thread=ThreadAddress(ProcessAddress(pid=1), tid=1), id=2), capa.features.insn.API("WriteFile"), ), ], ), }, ), }, ), }, ) def addresses(s) -> list[Address]: return sorted(i.address for i in s) def test_null_feature_extractor(): ph = ProcessHandle(ProcessAddress(pid=1), None) th = ThreadHandle(ThreadAddress(ProcessAddress(pid=1), tid=1), None) assert addresses(EXTRACTOR.get_processes()) == [ProcessAddress(pid=1)] assert addresses(EXTRACTOR.get_threads(ph)) == [ThreadAddress(ProcessAddress(pid=1), tid=1)] assert addresses(EXTRACTOR.get_calls(ph, th)) == [ DynamicCallAddress(thread=ThreadAddress(ProcessAddress(pid=1), tid=1), id=1), DynamicCallAddress(thread=ThreadAddress(ProcessAddress(pid=1), tid=1), id=2), ] rules = capa.rules.RuleSet( [ capa.rules.Rule.from_yaml( textwrap.dedent( """ rule: meta: name: create file scopes: static: basic block dynamic: call features: - and: - api: CreateFile """ ) ), ] ) capabilities = capa.main.find_capabilities(rules, EXTRACTOR) assert "create file" in capabilities.matches def compare_extractors(a: DynamicFeatureExtractor, b: DynamicFeatureExtractor): assert list(a.extract_file_features()) == list(b.extract_file_features()) assert addresses(a.get_processes()) == addresses(b.get_processes()) for p in a.get_processes(): assert addresses(a.get_threads(p)) == addresses(b.get_threads(p)) assert sorted(set(a.extract_process_features(p))) == sorted(set(b.extract_process_features(p))) for t in a.get_threads(p): assert addresses(a.get_calls(p, t)) == addresses(b.get_calls(p, t)) assert sorted(set(a.extract_thread_features(p, t))) == sorted(set(b.extract_thread_features(p, t))) for c in a.get_calls(p, t): assert sorted(set(a.extract_call_features(p, t, c))) == sorted(set(b.extract_call_features(p, t, c))) def test_freeze_str_roundtrip(): load = capa.features.freeze.loads dump = capa.features.freeze.dumps reanimated = load(dump(EXTRACTOR)) compare_extractors(EXTRACTOR, reanimated) def test_freeze_bytes_roundtrip(): load = capa.features.freeze.load dump = capa.features.freeze.dump reanimated = load(dump(EXTRACTOR)) compare_extractors(EXTRACTOR, reanimated) def test_freeze_load_sample(tmpdir): o = tmpdir.mkdir("capa").join("test.frz") extractor = fixtures.get_cape_extractor(fixtures.get_data_path_by_name("d46900")) Path(o.strpath).write_bytes(capa.features.freeze.dump(extractor)) null_extractor = capa.features.freeze.load(Path(o.strpath).read_bytes()) compare_extractors(extractor, null_extractor)