def get_auth_data(filename):
with open(filename, 'rb') as objf:
fingerprinter = fingerprint.Fingerprinter(objf)
fingerprinter.EvalGeneric()
results = fingerprinter.HashIt()
signed_pecoffs = [
x for x in results if x['name'] == 'pecoff' and 'SignedData' in x
]
if not signed_pecoffs:
print('This PE/COFF binary has no signature. Exiting.')
return
signed_pecoff = signed_pecoffs[0]
signed_datas = signed_pecoff['SignedData']
# There may be multiple of these, if the windows binary was signed multiple
# times, e.g. by different entities. Each of them adds a complete SignedData
# blob to the binary.
# TODO(user): Process all instances
signed_data = signed_datas[0]
blob = pecoff_blob.PecoffBlob(signed_data)
auth = auth_data.AuthData(blob.getCertificateBlob())
content_hasher_name = auth.digest_algorithm().name
computed_content_hash = signed_pecoff[content_hasher_name]
return auth, computed_content_hash
def testRunTestData(self):
# Walk through one data file in the test_data folder, and compare output
# with precomputed expected output.
data_file = os.path.join('test_data', 'SoftwareUpdate.exe.res')
with file(data_file, 'rb') as resf:
exp_results = pickle.load(resf)
# Make sure we have loaded the right data.
expected_generic_sha1 = '8322f1c2c355d88432f1f03a1f231f63912186bd'
loaded_generic_hashes = [
x for x in exp_results if x['name'] == 'generic'
]
loaded_generic_sha1 = loaded_generic_hashes[0]['sha1'].encode('hex')
self.assertEquals(expected_generic_sha1, loaded_generic_sha1)
signed_pecoffs = [
x for x in exp_results
if x['name'] == 'pecoff' and 'SignedData' in x
]
# If the invoker of the fingerprinter specified multiple fingers for pecoff
# hashing (possible, even if not sensible), then there can be more than one
# entry in this list. Should not be the case for this sample.
self.assertEquals(len(signed_pecoffs), 1)
signed_pecoff = signed_pecoffs[0]
# Make sure PE/COFF hashes match as well. Again, just a sanity check.
expected_auth_sha1 = '978b90ace99c764841d2dd17d278fac4149962a3'
loaded_auth_sha1 = signed_pecoff['sha1'].encode('hex')
self.assertEquals(expected_auth_sha1, loaded_auth_sha1)
signed_datas = signed_pecoff['SignedData']
# There may be multiple of these, if the windows binary was signed multiple
# times, e.g. by different entities. Each of them adds a complete SignedData
# blob to the binary. For our sample, there is only one blob.
self.assertEquals(len(signed_datas), 1)
signed_data = signed_datas[0]
blob = pecoff_blob.PecoffBlob(signed_data)
auth = auth_data.AuthData(blob.getCertificateBlob())
content_hasher_name = auth.digest_algorithm().name
computed_content_hash = signed_pecoff[content_hasher_name]
try:
auth.ValidateAsn1()
auth.ValidateHashes(computed_content_hash)
auth.ValidateSignatures()
auth.ValidateCertChains(time.gmtime())
except auth_data.Asn1Error:
if auth.openssl_error:
print('OpenSSL Errors:\n%s' % auth.openssl_error)
raise
print('Program: %s, URL: %s' % (auth.program_name, auth.program_url))
print('countersig: %d' % auth.has_countersignature)
print('Timestamp: %s' % auth.counter_timestamp)
self.assertEquals(auth.trailing_data.encode('hex'), '00')
def main():
data_file = sys.argv[1]
with file(data_file, 'rb') as objf:
fingerprinter = fingerprint.Fingerprinter(objf)
is_pecoff = fingerprinter.EvalPecoff()
fingerprinter.EvalGeneric()
results = fingerprinter.HashIt()
print('Generic hashes:')
hashes = [x for x in results if x['name'] == 'generic']
if len(hashes) > 1:
print('More than one generic finger? Only printing first one.')
for hname in sorted(hashes[0].keys()):
if hname != 'name':
print('%s: %s' % (hname, hashes[0][hname].encode('hex')))
print
if not is_pecoff:
print('This is not a PE/COFF binary. Exiting.')
return
print('PE/COFF hashes:')
hashes = [x for x in results if x['name'] == 'pecoff']
if len(hashes) > 1:
print('More than one PE/COFF finger? Only printing first one.')
for hname in sorted(hashes[0].keys()):
if hname != 'name' and hname != 'SignedData':
print('%s: %s' % (hname, hashes[0][hname].encode('hex')))
print
signed_pecoffs = [
x for x in results if x['name'] == 'pecoff' and 'SignedData' in x
]
if not signed_pecoffs:
print('This PE/COFF binary has no signature. Exiting.')
return
signed_pecoff = signed_pecoffs[0]
signed_datas = signed_pecoff['SignedData']
if len(signed_datas) > 1:
raise Exception(
"TODO Add support for printing more than one certificate")
# There may be multiple of these, if the windows binary was signed multiple
# times, e.g. by different entities. Each of them adds a complete SignedData
# blob to the binary.
# TODO(user): Process all instances
signed_data = signed_datas[0]
debugging_fd = open(
'/tmp/%s_extracted_cert.p7b' % os.path.basename(data_file), 'wb')
debugging_fd.write(signed_data[2])
debugging_fd.close()
blob = pecoff_blob.PecoffBlob(signed_data)
auth = auth_data.AuthData(blob.getCertificateBlob())
content_hasher_name = auth.digest_algorithm().name
computed_content_hash = signed_pecoff[content_hasher_name]
try:
auth.ValidateAsn1()
auth.ValidateHashes(computed_content_hash)
auth.ValidateSignatures()
auth.ValidateCertChains(time.gmtime())
except auth_data.Asn1Error:
if auth.openssl_error:
print('OpenSSL Errors:\n%s' % auth.openssl_error)
raise
print('Program: %s, URL: %s' % (repr(auth.program_name), auth.program_url))
if auth.has_countersignature:
print('Countersignature is present. Timestamp: %s UTC' %
time.asctime(time.gmtime(auth.counter_timestamp)))
else:
print('Countersignature is not present.')
print('Binary is signed with cert issued by:')
pprint.pprint(auth.signing_cert_id)
print
print('Cert chain head issued by:')
pprint.pprint(auth.cert_chain_head[2])
print(' Chain not before: %s UTC' %
(time.asctime(time.gmtime(auth.cert_chain_head[0]))))
print(' Chain not after: %s UTC' %
(time.asctime(time.gmtime(auth.cert_chain_head[1]))))
print
if auth.has_countersignature:
print('Countersig chain head issued by:')
pprint.pprint(auth.counter_chain_head[2])
print(' Countersig not before: %s UTC' %
(time.asctime(time.gmtime(auth.counter_chain_head[0]))))
print(' Countersig not after: %s UTC' %
(time.asctime(time.gmtime(auth.counter_chain_head[1]))))
print
print('Certificates')
for (issuer, serial), cert in auth.certificates.items():
print(' Issuer: %s' % issuer)
print(' Serial: %s' % serial)
subject = cert[0][0]['subject']
subject_dn = str(dn.DistinguishedName.TraverseRdn(subject[0]))
print(' Subject: %s' % subject_dn)
not_before = cert[0][0]['validity']['notBefore']
not_after = cert[0][0]['validity']['notAfter']
not_before_time = not_before.ToPythonEpochTime()
not_after_time = not_after.ToPythonEpochTime()
print(' Not Before: %s UTC (%s)' %
(time.asctime(time.gmtime(not_before_time)), not_before[0]))
print(' Not After: %s UTC (%s)' %
(time.asctime(time.gmtime(not_after_time)), not_after[0]))
bin_cert = der_encoder.encode(cert)
print(' MD5: %s' % hashlib.md5(bin_cert).hexdigest())
print(' SHA1: %s' % hashlib.sha1(bin_cert).hexdigest())
print
if auth.trailing_data:
print('Signature Blob had trailing (unvalidated) data (%d bytes): %s' %
(len(auth.trailing_data), auth.trailing_data.encode('hex')))
