import textwrap import capa.main import capa.helpers import capa.features import capa.features.insn import capa.features.extractors import capa.features.freeze from fixtures import * EXTRACTOR = capa.features.extractors.NullFeatureExtractor({ 'file features': [ (0x402345, capa.features.Characteristic('embedded pe')), ], 'functions': { 0x401000: { 'features': [ (0x401000, capa.features.Characteristic('switch')), ], 'basic blocks': { 0x401000: { 'features': [ (0x401000, capa.features.Characteristic('tight loop')), ], 'instructions': { 0x401000: { 'features': [ (0x401000, capa.features.insn.Mnemonic('xor')), (0x401000, capa.features.Characteristic('nzxor')), ], }, }, }, }, }, } ) def test_null_feature_extractor(): assert list(EXTRACTOR.get_functions()) == [0x401000] assert list(EXTRACTOR.get_basic_blocks(0x401000)) == [0x401000] assert list(EXTRACTOR.get_instructions(0x401000, 0x0401000)) == [0x401000, 0x401002] rules = capa.rules.RuleSet([ capa.rules.Rule.from_yaml(textwrap.dedent(''' rule: meta: name: xor loop scope: basic block features: - and: - characteristic: tight loop - mnemonic: xor - characteristic: nzxor ''')), ]) capabilities = capa.main.find_capabilities(rules, EXTRACTOR) assert "xor loop" in capabilities def compare_extractors(a, b): """ args: a (capa.features.extractors.NullFeatureExtractor) b (capa.features.extractors.NullFeatureExtractor) """ # TODO: ordering of these things probably doesn't work yet assert list(a.extract_file_features()) == list(b.extract_file_features()) assert list(a.get_functions()) == list(b.get_functions()) for f in a.get_functions(): assert list(a.get_basic_blocks(f)) == list(b.get_basic_blocks(f)) assert list(a.extract_function_features(f)) == list( b.extract_function_features(f) ) for bb in a.get_basic_blocks(f): assert list(a.get_instructions(f, bb)) == list(b.get_instructions(f, bb)) assert list(a.extract_basic_block_features(f, bb)) == list( b.extract_basic_block_features(f, bb) ) for insn in a.get_instructions(f, bb): assert list(a.extract_insn_features(f, bb, insn)) == list( b.extract_insn_features(f, bb, insn) ) def compare_extractors_viv_null(viv_ext, null_ext): """ almost identical to compare_extractors but adds casts to ints since the VivisectFeatureExtractor returns objects and NullFeatureExtractor returns ints args: viv_ext (capa.features.extractors.viv.VivisectFeatureExtractor) null_ext (capa.features.extractors.NullFeatureExtractor) """ # TODO: ordering of these things probably doesn't work yet assert list(viv_ext.extract_file_features()) == list( null_ext.extract_file_features() ) assert to_int(list(viv_ext.get_functions())) == list(null_ext.get_functions()) for f in viv_ext.get_functions(): assert to_int(list(viv_ext.get_basic_blocks(f))) == list( null_ext.get_basic_blocks(to_int(f)) ) assert list(viv_ext.extract_function_features(f)) == list( null_ext.extract_function_features(to_int(f)) ) for bb in viv_ext.get_basic_blocks(f): assert to_int(list(viv_ext.get_instructions(f, bb))) == list( null_ext.get_instructions(to_int(f), to_int(bb)) ) assert list(viv_ext.extract_basic_block_features(f, bb)) == list( null_ext.extract_basic_block_features(to_int(f), to_int(bb)) ) for insn in viv_ext.get_instructions(f, bb): assert list(viv_ext.extract_insn_features(f, bb, insn)) == list( null_ext.extract_insn_features(to_int(f), to_int(bb), to_int(insn)) ) def to_int(o): """helper to get int value of extractor items""" if isinstance(o, list): return map(lambda x: capa.helpers.oint(x), o) else: return capa.helpers.oint(o) def test_freeze_s_roundtrip(): load = capa.features.freeze.loads dump = capa.features.freeze.dumps reanimated = load(dump(EXTRACTOR)) compare_extractors(EXTRACTOR, reanimated) def test_freeze_b_roundtrip(): load = capa.features.freeze.load dump = capa.features.freeze.dump reanimated = load(dump(EXTRACTOR)) compare_extractors(EXTRACTOR, reanimated) def roundtrip_feature(feature): serialize = capa.features.freeze.serialize_feature deserialize = capa.features.freeze.deserialize_feature assert feature == deserialize(serialize(feature)) def test_serialize_features(): roundtrip_feature(capa.features.insn.API("advapi32.CryptAcquireContextW")) roundtrip_feature(capa.features.String("SCardControl")) roundtrip_feature(capa.features.insn.Number(0xFF)) roundtrip_feature(capa.features.insn.Offset(0x0)) roundtrip_feature(capa.features.insn.Mnemonic('push')) roundtrip_feature(capa.features.file.Section('.rsrc')) roundtrip_feature(capa.features.Characteristic('tight loop')) roundtrip_feature(capa.features.basicblock.BasicBlock()) roundtrip_feature(capa.features.file.Export("BaseThreadInitThunk")) roundtrip_feature(capa.features.file.Import("kernel32.IsWow64Process")) roundtrip_feature(capa.features.file.Import("#11")) def test_freeze_sample(tmpdir, sample_9324d1a8ae37a36ae560c37448c9705a): # tmpdir fixture handles cleanup o = tmpdir.mkdir("capa").join("test.frz").strpath assert ( capa.features.freeze.main( [sample_9324d1a8ae37a36ae560c37448c9705a.path, o, "-v"] ) == 0 ) def test_freeze_load_sample(tmpdir, sample_9324d1a8ae37a36ae560c37448c9705a): o = tmpdir.mkdir("capa").join("test.frz") viv_extractor = capa.features.extractors.viv.VivisectFeatureExtractor( sample_9324d1a8ae37a36ae560c37448c9705a.vw, sample_9324d1a8ae37a36ae560c37448c9705a.path, ) with open(o.strpath, "wb") as f: f.write(capa.features.freeze.dump(viv_extractor)) null_extractor = capa.features.freeze.load(o.open("rb").read()) compare_extractors_viv_null(viv_extractor, null_extractor)