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import binascii
import struct
from chrysacase import ChrysalideTestCase
from gi._constants import TYPE_INVALID
from pychrysalide.analysis.scan import ScanExpression
from pychrysalide.analysis.scan import ScanOptions
from pychrysalide.analysis.scan import find_token_modifiers_for_name
from pychrysalide.glibext import ComparableItem
class TestRostPythonAPI(ChrysalideTestCase):
"""TestCase for the ROST Python API."""
def testEmptyOptions(self):
"""Check default scan options."""
ops = ScanOptions()
self.assertEqual(ops.backend_for_data, TYPE_INVALID)
def testDirectInstancesOfExpression(self):
"""Reject direct instances of ROST expressions."""
with self.assertRaisesRegex(RuntimeError, 'pychrysalide.analysis.scan.ScanExpression is an abstract class'):
e = ScanExpression()
def testBooleanComparison(self):
"""Compare custom scan expressions."""
class StrLenExpr(ScanExpression):
def __init__(self, value):
super().__init__(ScanExpression.ScanReductionState.REDUCED)
self._value = value
def _cmp_rich(self, other, op):
if op == ComparableItem.RichCmpOperation.EQ:
return len(self._value) == len(other._value)
e0 = StrLenExpr('00000000000')
e1 = StrLenExpr('00000000000')
e2 = StrLenExpr('000000000000000000000000000')
self.assertTrue(e0 == e1)
# !?
# Python teste e0 != e1 (non implémenté), puis e1 != e0 (pareil) et en déduit une différence !
# self.assertFalse(e0 != e1)
self.assertFalse(e0 == e2)
# TypeError: '<' not supported between instances of 'StrLenExpr' and 'StrLenExpr'
with self.assertRaisesRegex(TypeError, '\'<\' not supported between instances'):
self.assertTrue(e0 < e1)
def testBytePatternModifiers(self):
"""Validate the bytes produced by modifiers."""
mod = find_token_modifiers_for_name('plain')
self.assertIsNotNone(mod)
source = b'ABC'
transformed = mod.transform(source)
self.assertEqual(source, transformed[0])
mod = find_token_modifiers_for_name('hex')
self.assertIsNotNone(mod)
source = b'ABC'
transformed = mod.transform(source)
self.assertEqual(binascii.hexlify(source), transformed[0])
mod = find_token_modifiers_for_name('rev')
self.assertIsNotNone(mod)
source = b'ABC'
transformed = mod.transform(source)
self.assertEqual(source[::-1], transformed[0])
mod = find_token_modifiers_for_name('lower')
self.assertIsNotNone(mod)
source = b'AbC'
transformed = mod.transform(source)
self.assertEqual(source.lower(), transformed[0])
mod = find_token_modifiers_for_name('upper')
self.assertIsNotNone(mod)
source = b'AbC'
transformed = mod.transform(source)
self.assertEqual(source.upper(), transformed[0])
mod = find_token_modifiers_for_name('wide')
self.assertIsNotNone(mod)
source = b'ABC'
transformed = mod.transform(source)
self.assertEqual(source.decode('ascii'), transformed[0].decode('utf-16-le'))
mod = find_token_modifiers_for_name('base64')
self.assertIsNotNone(mod)
source = b'ABC'
transformed = mod.transform(source)
self.assertEqual(len(transformed), 3)
self.assertEqual(transformed[0], b'QUJD')
self.assertEqual(transformed[1], b'FCQ')
self.assertEqual(transformed[2], b'BQk')
def testClassicalAPIHashing(self):
"""Reproduce classical API Hashing results."""
def b2i(t):
return struct.unpack('<I', t)[0]
# Example:
# - PlugX (2020) - https://vms.drweb.fr/virus/?i=21512304
mod = find_token_modifiers_for_name('crc32')
self.assertIsNotNone(mod)
source = b'GetCurrentProcess\x00'
transformed = mod.transform(source)
self.assertEqual(b2i(transformed[0]), 0x3690e66)
# Example:
# - GuLoader (2020) - https://www.crowdstrike.com/blog/guloader-malware-analysis/
mod = find_token_modifiers_for_name('djb2')
self.assertIsNotNone(mod)
source = b'GetProcAddress'
transformed = mod.transform(source)
self.assertEqual(b2i(transformed[0]), 0xcf31bb1f)
def testCustomAPIHashing(self):
"""Reproduce custom API Hashing results."""
def b2i(t):
return struct.unpack('<I', t)[0]
# Example:
# Underminer Exploit Kit (2019) - https://jsac.jpcert.or.jp/archive/2019/pdf/JSAC2019_1_koike-nakajima_jp.pdf
mod = find_token_modifiers_for_name('add1505-shl5')
self.assertIsNotNone(mod)
source = b'LoadLibraryA'
transformed = mod.transform(source)
self.assertEqual(b2i(transformed[0]), 0x5fbff0fb)
# Example:
# Enigma Stealer (2023) https://www.trendmicro.com/es_mx/research/23/b/enigma-stealer-targets-cryptocurrency-industry-with-fake-jobs.html
mod = find_token_modifiers_for_name('enigma-murmur')
self.assertIsNotNone(mod)
source = b'CreateMutexW'
transformed = mod.transform(source)
self.assertEqual(b2i(transformed[0]), 0xfd43765a)
# Examples:
# - ShadowHammer (2019) - https://blog.f-secure.com/analysis-shadowhammer-asus-attack-first-stage-payload/
# - ShadowHammer (2019) - https://securelist.com/operation-shadowhammer-a-high-profile-supply-chain-attack/90380/
mod = find_token_modifiers_for_name('imul21-add')
self.assertIsNotNone(mod)
source = b'VirtualAlloc'
transformed = mod.transform(source)
self.assertEqual(b2i(transformed[0]), 0xdf894b12)
# Examples:
# - Bottle Exploit Kit (2019) - https://nao-sec.org/2019/12/say-hello-to-bottle-exploit-kit.html
# - ShadowHammer (2019) - https://securelist.com/operation-shadowhammer-a-high-profile-supply-chain-attack/90380/
mod = find_token_modifiers_for_name('imul83-add')
self.assertIsNotNone(mod)
source = b'GetProcAddress'
transformed = mod.transform(source)
self.assertEqual(b2i(transformed[0]), 0x9ab9b854)
# Examples:
# - ?? (2021) - https://www.threatspike.com/blogs/reflective-dll-injection
# - Mustang Panda (2022) - https://blog.talosintelligence.com/mustang-panda-targets-europe/
mod = find_token_modifiers_for_name('ror13')
self.assertIsNotNone(mod)
source = b'GetProcAddress'
transformed = mod.transform(source)
self.assertEqual(b2i(transformed[0]), 0x7c0dfcaa)
source = b'VirtualAlloc'
transformed = mod.transform(source)
self.assertEqual(b2i(transformed[0]), 0x91afca54)
# Example:
# - Energetic Bear (2019) - https://insights.sei.cmu.edu/blog/api-hashing-tool-imagine-that/
mod = find_token_modifiers_for_name('sll1-add-hash32')
self.assertIsNotNone(mod)
source = b'LoadLibraryA'
transformed = mod.transform(source)
self.assertEqual(b2i(transformed[0]), 0x000d5786)
# Example:
# - SideWinder/WarHawk (2022) - https://www.zscaler.com/blogs/security-research/warhawk-new-backdoor-arsenal-sidewinder-apt-group
mod = find_token_modifiers_for_name('sub42')
self.assertIsNotNone(mod)
source = b'LoadLibraryA'
transformed = mod.transform(source)
self.assertEqual(transformed[0], b'\x8e\xb1\xa3\xa6\x8e\xab\xa4\xb4\xa3\xb4\xbb\x83')
# Example:
# - TrickBot (2021) - https://medium.com/walmartglobaltech/trickbot-crews-new-cobaltstrike-loader-32c72b78e81c
mod = find_token_modifiers_for_name('sub-index1')
self.assertIsNotNone(mod)
source = b'raw.githubusercontent.com'
transformed = mod.transform(source)
self.assertEqual(transformed[0], b'\x73\x63\x7a\x32\x6c\x6f\x7b\x70\x7e\x6c\x80\x7f\x72\x80\x72\x7f\x7f\x86\x78\x82\x89\x44\x7a\x87\x86')
def testBytePatternModifiersAPI(self):
"""Validate the API for pattern modifiers."""
mod = find_token_modifiers_for_name('plain')
self.assertIsNotNone(mod)
source = [ b'ABC', b'01234' ]
transformed = mod.transform(source)
self.assertEqual(len(source), len(transformed))
self.assertEqual(source[0], transformed[0])
self.assertEqual(source[1], transformed[1])
mod = find_token_modifiers_for_name('xor')
self.assertIsNotNone(mod)
source = [ b'ABC' ]
transformed = mod.transform(source, 0x20)
self.assertEqual(transformed[0], b'abc')
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