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441 lines
14 KiB
Python
441 lines
14 KiB
Python
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
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import textwrap
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import capa.rules
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import capa.engine
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from capa.engine import *
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from capa.features import *
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from capa.features.insn import *
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def test_number():
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assert Number(1).evaluate({Number(0): {1}}) == False
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assert Number(1).evaluate({Number(1): {1}}) == True
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assert Number(1).evaluate({Number(2): {1, 2}}) == False
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def test_and():
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assert And(Number(1)).evaluate({Number(0): {1}}) == False
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assert And(Number(1)).evaluate({Number(1): {1}}) == True
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assert And(Number(1), Number(2)).evaluate({Number(0): {1}}) == False
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assert And(Number(1), Number(2)).evaluate({Number(1): {1}}) == False
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assert And(Number(1), Number(2)).evaluate({Number(2): {1}}) == False
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assert And(Number(1), Number(2)).evaluate({Number(1): {1}, Number(2): {2}}) == True
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def test_or():
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assert Or(Number(1)).evaluate({Number(0): {1}}) == False
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assert Or(Number(1)).evaluate({Number(1): {1}}) == True
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assert Or(Number(1), Number(2)).evaluate({Number(0): {1}}) == False
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assert Or(Number(1), Number(2)).evaluate({Number(1): {1}}) == True
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assert Or(Number(1), Number(2)).evaluate({Number(2): {1}}) == True
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assert Or(Number(1), Number(2)).evaluate({Number(1): {1}, Number(2): {2}}) == True
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def test_not():
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assert Not(Number(1)).evaluate({Number(0): {1}}) == True
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assert Not(Number(1)).evaluate({Number(1): {1}}) == False
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def test_some():
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assert Some(0, Number(1)).evaluate({Number(0): {1}}) == True
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assert Some(1, Number(1)).evaluate({Number(0): {1}}) == False
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assert Some(2, Number(1), Number(2), Number(3)).evaluate({Number(0): {1}}) == False
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assert Some(2, Number(1), Number(2), Number(3)).evaluate({Number(0): {1}, Number(1): {1}}) == False
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assert Some(2, Number(1), Number(2), Number(3)).evaluate({Number(0): {1}, Number(1): {1}, Number(2): {1}}) == True
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assert (
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Some(2, Number(1), Number(2), Number(3)).evaluate(
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{Number(0): {1}, Number(1): {1}, Number(2): {1}, Number(3): {1}}
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)
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== True
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)
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assert (
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Some(2, Number(1), Number(2), Number(3)).evaluate(
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{Number(0): {1}, Number(1): {1}, Number(2): {1}, Number(3): {1}, Number(4): {1},}
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)
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== True
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)
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def test_complex():
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assert True == Or(And(Number(1), Number(2)), Or(Number(3), Some(2, Number(4), Number(5), Number(6))),).evaluate(
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{Number(5): {1}, Number(6): {1}, Number(7): {1}, Number(8): {1}}
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)
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assert False == Or(And(Number(1), Number(2)), Or(Number(3), Some(2, Number(4), Number(5)))).evaluate(
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{Number(5): {1}, Number(6): {1}, Number(7): {1}, Number(8): {1}}
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)
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def test_range():
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# unbounded range, but no matching feature
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# since the lower bound is zero, and there are zero matches, ok
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assert Range(Number(1)).evaluate({Number(2): {}}) == True
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# unbounded range with matching feature should always match
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assert Range(Number(1)).evaluate({Number(1): {}}) == True
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assert Range(Number(1)).evaluate({Number(1): {0}}) == True
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# unbounded max
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assert Range(Number(1), min=1).evaluate({Number(1): {0}}) == True
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assert Range(Number(1), min=2).evaluate({Number(1): {0}}) == False
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assert Range(Number(1), min=2).evaluate({Number(1): {0, 1}}) == True
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# unbounded min
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assert Range(Number(1), max=0).evaluate({Number(1): {0}}) == False
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assert Range(Number(1), max=1).evaluate({Number(1): {0}}) == True
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assert Range(Number(1), max=2).evaluate({Number(1): {0}}) == True
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assert Range(Number(1), max=2).evaluate({Number(1): {0, 1}}) == True
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assert Range(Number(1), max=2).evaluate({Number(1): {0, 1, 3}}) == False
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# we can do an exact match by setting min==max
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assert Range(Number(1), min=1, max=1).evaluate({Number(1): {}}) == False
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assert Range(Number(1), min=1, max=1).evaluate({Number(1): {1}}) == True
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assert Range(Number(1), min=1, max=1).evaluate({Number(1): {1, 2}}) == False
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# bounded range
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assert Range(Number(1), min=1, max=3).evaluate({Number(1): {}}) == False
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assert Range(Number(1), min=1, max=3).evaluate({Number(1): {1}}) == True
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assert Range(Number(1), min=1, max=3).evaluate({Number(1): {1, 2}}) == True
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assert Range(Number(1), min=1, max=3).evaluate({Number(1): {1, 2, 3}}) == True
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assert Range(Number(1), min=1, max=3).evaluate({Number(1): {1, 2, 3, 4}}) == False
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def test_range_exact():
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rule = textwrap.dedent(
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"""
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rule:
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meta:
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name: test rule
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features:
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- count(number(100)): 2
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"""
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)
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r = capa.rules.Rule.from_yaml(rule)
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# just enough matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1, 2}}, 0x0)
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assert "test rule" in matches
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# not enough matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1}}, 0x0)
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assert "test rule" not in matches
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# too many matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1, 2, 3}}, 0x0)
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assert "test rule" not in matches
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def test_range_range():
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rule = textwrap.dedent(
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"""
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rule:
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meta:
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name: test rule
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features:
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- count(number(100)): (2, 3)
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"""
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)
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r = capa.rules.Rule.from_yaml(rule)
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# just enough matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1, 2}}, 0x0)
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assert "test rule" in matches
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# enough matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1, 2, 3}}, 0x0)
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assert "test rule" in matches
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# not enough matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1}}, 0x0)
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assert "test rule" not in matches
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# too many matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1, 2, 3, 4}}, 0x0)
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assert "test rule" not in matches
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def test_range_exact_zero():
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rule = textwrap.dedent(
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"""
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rule:
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meta:
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name: test rule
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features:
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- count(number(100)): 0
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"""
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)
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r = capa.rules.Rule.from_yaml(rule)
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# feature isn't indexed - good.
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features, matches = capa.engine.match([r], {}, 0x0)
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assert "test rule" in matches
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# feature is indexed, but no matches.
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# i don't think we should ever really have this case, but good to check anyways.
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {}}, 0x0)
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assert "test rule" in matches
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# too many matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1}}, 0x0)
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assert "test rule" not in matches
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def test_range_with_zero():
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rule = textwrap.dedent(
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"""
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rule:
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meta:
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name: test rule
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features:
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- count(number(100)): (0, 1)
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"""
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)
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r = capa.rules.Rule.from_yaml(rule)
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# ok
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features, matches = capa.engine.match([r], {}, 0x0)
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assert "test rule" in matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {}}, 0x0)
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assert "test rule" in matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1}}, 0x0)
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assert "test rule" in matches
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# too many matches
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1, 2}}, 0x0)
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assert "test rule" not in matches
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def test_match_adds_matched_rule_feature():
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"""show that using `match` adds a feature for matched rules."""
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rule = textwrap.dedent(
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"""
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rule:
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meta:
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name: test rule
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features:
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- number: 100
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"""
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)
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r = capa.rules.Rule.from_yaml(rule)
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features, matches = capa.engine.match([r], {capa.features.insn.Number(100): {1}}, 0x0)
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assert capa.features.MatchedRule("test rule") in features
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def test_match_matched_rules():
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"""show that using `match` adds a feature for matched rules."""
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rules = [
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: test rule1
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features:
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- number: 100
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"""
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)
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),
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: test rule2
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features:
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- match: test rule1
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"""
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)
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),
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]
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(rules), {capa.features.insn.Number(100): {1}}, 0x0,
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)
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assert capa.features.MatchedRule("test rule1") in features
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assert capa.features.MatchedRule("test rule2") in features
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# the ordering of the rules must not matter,
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# the engine should match rules in an appropriate order.
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(reversed(rules)), {capa.features.insn.Number(100): {1}}, 0x0,
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)
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assert capa.features.MatchedRule("test rule1") in features
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assert capa.features.MatchedRule("test rule2") in features
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def test_regex():
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rules = [
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: test rule
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features:
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- and:
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- string: /.*bbbb.*/
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"""
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)
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),
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: rule with implied wildcards
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features:
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- and:
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- string: /bbbb/
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"""
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)
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),
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: rule with anchor
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features:
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- and:
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- string: /^bbbb/
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"""
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)
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),
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]
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(rules), {capa.features.insn.Number(100): {1}}, 0x0,
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)
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assert capa.features.MatchedRule("test rule") not in features
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(rules), {capa.features.String("aaaa"): {1}}, 0x0,
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)
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assert capa.features.MatchedRule("test rule") not in features
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(rules), {capa.features.String("aBBBBa"): {1}}, 0x0,
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)
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assert capa.features.MatchedRule("test rule") not in features
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(rules), {capa.features.String("abbbba"): {1}}, 0x0,
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)
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assert capa.features.MatchedRule("test rule") in features
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assert capa.features.MatchedRule("rule with implied wildcards") in features
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assert capa.features.MatchedRule("rule with anchor") not in features
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def test_regex_ignorecase():
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rules = [
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: test rule
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features:
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- and:
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- string: /.*bbbb.*/i
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"""
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)
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),
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]
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(rules), {capa.features.String("aBBBBa"): {1}}, 0x0,
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)
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assert capa.features.MatchedRule("test rule") in features
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def test_regex_complex():
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rules = [
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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r"""
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rule:
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meta:
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name: test rule
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features:
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- or:
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- string: /.*HARDWARE\\Key\\key with spaces\\.*/i
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"""
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)
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),
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]
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(rules),
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{capa.features.String(r"Hardware\Key\key with spaces\some value"): {1}},
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0x0,
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)
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assert capa.features.MatchedRule("test rule") in features
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def test_match_namespace():
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rules = [
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: CreateFile API
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namespace: file/create/CreateFile
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features:
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- api: CreateFile
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"""
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)
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),
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: WriteFile API
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namespace: file/write
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features:
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- api: WriteFile
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"""
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)
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),
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: file-create
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features:
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- match: file/create
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"""
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)
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),
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capa.rules.Rule.from_yaml(
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textwrap.dedent(
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"""
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rule:
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meta:
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name: filesystem-any
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features:
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- match: file
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"""
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)
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),
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]
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(rules), {capa.features.insn.API("CreateFile"): {1}}, 0x0,
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)
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assert "CreateFile API" in matches
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assert "file-create" in matches
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assert "filesystem-any" in matches
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assert capa.features.MatchedRule("file") in features
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assert capa.features.MatchedRule("file/create") in features
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assert capa.features.MatchedRule("file/create/CreateFile") in features
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features, matches = capa.engine.match(
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capa.engine.topologically_order_rules(rules), {capa.features.insn.API("WriteFile"): {1}}, 0x0,
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)
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assert "WriteFile API" in matches
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assert "file-create" not in matches
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assert "filesystem-any" in matches
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