def test_wrapping_attack(self):
"""
Test resistance to attempted wrapping attack
"""
case = self.cases['SAML_assertion1']
print("XML input :\n{}\n\n".format(case.as_buf('in.xml')))
tbs = case.as_etree('in.xml')
signed = xmlsec.sign(tbs,
key_spec=self.private_keyspec,
cert_spec=self.public_keyspec)
attack = case.as_etree('evil.xml')
attack.append(signed)
refs = xmlsec.verified(attack, self.public_keyspec)
self.assertTrue(len(refs) == 1)
print("verified XML: %s" % etree.tostring(refs[0]))
seen_foo = False
seen_bar = False
for av in refs[0].findall(".//{%s}AttributeValue" %
'urn:oasis:names:tc:SAML:2.0:assertion'):
print(etree.tostring(av))
print(av.text)
if av.text == 'Foo':
seen_foo = True
elif av.text == 'Bar':
seen_bar = True
self.assertTrue(av.text != 'admin')
self.assertTrue(seen_foo and seen_bar)
def test_sign_alert_signed(self):
"""Tests alert signature creation."""
plain_alert = etree.fromstring(self.valid_alert_content)
signed_alert = utils.SignAlert(plain_alert, self.TEST_USER_NAME)
cert_path = os.path.join(settings.CREDENTIALS_DIR,
self.TEST_USER_NAME + ".cert")
self.assertTrue(xmlsec.verified(signed_alert, cert_path))
def test_wrapping_attack(self):
"""
Test resistance to attempted wrapping attack
"""
case = self.cases['SAML_assertion1']
print("XML input :\n{}\n\n".format(case.as_buf('in.xml')))
tbs = case.as_etree('in.xml')
signed = xmlsec.sign(tbs,
key_spec=self.private_keyspec,
cert_spec=self.public_keyspec)
attack = case.as_etree('evil.xml')
attack.append(signed)
refs = xmlsec.verified(attack, self.public_keyspec)
self.assertTrue(len(refs) == 1)
print("verified XML: %s" % etree.tostring(refs[0]))
seen_foo = False
seen_bar = False
for av in refs[0].findall(".//{%s}AttributeValue" % 'urn:oasis:names:tc:SAML:2.0:assertion'):
print(etree.tostring(av))
print(av.text)
if av.text == 'Foo':
seen_foo = True
elif av.text == 'Bar':
seen_bar = True
self.assertTrue(av.text != 'admin')
self.assertTrue(seen_foo and seen_bar)
def test_sign_alert_signed(self):
"""Tests alert signature creation."""
plain_alert = etree.fromstring(self.valid_alert_content)
signed_alert = utils.SignAlert(plain_alert, self.TEST_USER_NAME)
cert_path = os.path.join(settings.CREDENTIALS_DIR,
self.TEST_USER_NAME + ".cert")
self.assertTrue(xmlsec.verified(signed_alert, cert_path))
def check_signature(t, key, only_one_signature=False):
if key is not None:
log.debug("verifying signature using %s" % key)
refs = xmlsec.verified(t, key, drop_signature=True)
if only_one_signature and len(refs) != 1:
raise MetadataException("XML metadata contains %d signatures - exactly 1 is required" % len(refs))
t = refs[0] # prevent wrapping attacks
return t
def check_signature(t, key, only_one_signature=False):
if key is not None:
log.debug("verifying signature using %s" % key)
refs = xmlsec.verified(t, key, drop_signature=True)
if only_one_signature and len(refs) != 1:
raise MetadataException("XML metadata contains %d signatures - exactly 1 is required" % len(refs))
t = refs[0] # prevent wrapping attacks
return t
def check_signature(self, t, key):
if key is not None:
if log.isDebugEnabled():
log.debug("verifying signature using %s" % key)
refs = xmlsec.verified(t, key)
if len(refs) != 1:
raise MetadataException("XML metadata contains %d signatures - exactly 1 is required" % len(refs))
t = refs[0] # prevent wrapping attacks
return t
def check_signature(self, t, key):
if key is not None:
if log.isDebugEnabled():
log.debug("verifying signature using %s" % key)
refs = xmlsec.verified(t, key)
if len(refs) != 1:
raise MetadataException(
"XML metadata contains %d signatures - exactly 1 is required"
% len(refs))
t = refs[0] # prevent wrapping attacks
return t
def parse_metadata(self,
fn,
key=None,
base_url=None,
fail_on_error=False,
filter_invalid=True,
validate=True,
post=None):
"""Parse a piece of XML and split it up into EntityDescriptor elements. Each such element
is stored in the MDRepository instance.
:param fn: a file-like object containing SAML metadata
:param key: a certificate (file) or a SHA1 fingerprint to use for signature verification
:param base_url: use this base url to resolve relative URLs for XInclude processing
:param fail_on_error: (default: False)
:param filter_invalid: (default True) remove invalid EntityDescriptor elements rather than raise an errror
:param validate: (default: True) set to False to turn off all XML schema validation
:param post: A callable that will be called to modify the parse-tree before any validation
(but after xinclude processing)
"""
try:
t = etree.parse(fn, base_url=base_url, parser=etree.XMLParser(resolve_entities=False))
t.xinclude()
if key is not None:
try:
log.debug("verifying signature using %s" % key)
refs = xmlsec.verified(t, key)
if len(refs) != 1:
raise MetadataException("XML metadata contains %d signatures - exactly 1 is required" % len(refs))
t = refs[0] # prevent wrapping attacks
except Exception, ex:
tb = traceback.format_exc()
print tb
log.error(ex)
return None
if post is not None:
t = post(t)
if validate:
if filter_invalid:
for e in t.findall('{%s}EntityDescriptor' % NS['md']):
if not schema().validate(e):
error = _e(schema().error_log, m=base_url)
log.debug("removing '%s': schema validation failed (%s)" % (e.get('entityID'), error))
e.getparent().remove(e)
self.fire(type=EVENT_DROP_ENTITY, url=base_url, entityID=e.get('entityID'), error=error)
else:
# Having removed the invalid entities this should now never happen...
schema().assertValid(t)
def test_duo_vuln_attack(self):
"""
Test https://duo.com/blog/duo-finds-saml-vulnerabilities-affecting-multiple-implementations
"""
case = self.cases['SAML_assertion_sha256']
print("XML input :\n{}\n\n".format(case.as_buf('in.xml')))
signed = xmlsec.sign(case.as_etree('in.xml'),
key_spec=self.private_keyspec,
cert_spec=self.public_keyspec)
refs = xmlsec.verified(signed, self.public_keyspec)
self.assertTrue(len(refs) == 1)
print("verified XML: %s" % etree.tostring(refs[0]))
assert('evil' not in [x.text for x in refs[0].findall(".//{%s}AttributeValue" % 'urn:oasis:names:tc:SAML:2.0:assertion')])
def test_duo_vuln_attack(self):
"""
Test https://duo.com/blog/duo-finds-saml-vulnerabilities-affecting-multiple-implementations
"""
case = self.cases['SAML_assertion_sha256']
print("XML input :\n{}\n\n".format(case.as_buf('in.xml')))
signed = xmlsec.sign(case.as_etree('in.xml'),
key_spec=self.private_keyspec,
cert_spec=self.public_keyspec)
refs = xmlsec.verified(signed, self.public_keyspec)
self.assertTrue(len(refs) == 1)
print("verified XML: %s" % etree.tostring(refs[0]))
assert('evil' not in [x.text for x in refs[0].findall(".//{%s}AttributeValue" % 'urn:oasis:names:tc:SAML:2.0:assertion')])
def test_sign_verify_SAML_assertion_unwrap2(self):
"""
Test signing a SAML assertion, and return verified data.
"""
case = self.cases['SAML_assertion1']
print("XML input :\n{}\n\n".format(case.as_buf('in.xml')))
tbs = case.as_etree('in.xml')
signed = xmlsec.sign(tbs,
key_spec=self.private_keyspec,
cert_spec=self.public_keyspec)
refs = xmlsec.verified(signed, self.public_keyspec)
self.assertTrue(len(refs) == 1)
print("verified XML: %s" % etree.tostring(refs[0]))
self.assertTrue(tbs.tag == refs[0].tag)
set1 = set(etree.tostring(i, method='c14n') for i in root(tbs))
set2 = set(etree.tostring(i, method='c14n') for i in root(refs[0]))
self.assertTrue(set1 == set2)
def test_sign_verify_SAML_assertion_unwrap2(self):
"""
Test signing a SAML assertion, and return verified data.
"""
case = self.cases['SAML_assertion1']
print("XML input :\n{}\n\n".format(case.as_buf('in.xml')))
tbs = case.as_etree('in.xml')
signed = xmlsec.sign(tbs,
key_spec=self.private_keyspec,
cert_spec=self.public_keyspec)
refs = xmlsec.verified(signed, self.public_keyspec)
self.assertTrue(len(refs) == 1)
print("verified XML: %s" % etree.tostring(refs[0]))
self.assertTrue(tbs.tag == refs[0].tag)
set1 = set(etree.tostring(i, method='c14n') for i in root(tbs))
set2 = set(etree.tostring(i, method='c14n') for i in root(refs[0]))
self.assertTrue(set1 == set2)
schema().assertValid(t)
except DocumentInvalid, ex:
traceback.print_exc()
log.debug("schema validation failed on '%s': %s" % (
base_url, _e(ex.error_log, m=base_url)))
raise MetadataException("schema validation failed")
except Exception, ex:
# log.debug(_e(schema().error_log))
log.error(ex)
if fail_on_error:
raise ex
return None
if key is not None:
try:
log.debug("verifying signature using %s" % key)
refs = xmlsec.verified(t, key)
if len(refs) != 1:
raise MetadataException(
"XML metadata contains %d signatures - exactly 1 is required" % len(refs))
t = refs[0] # prevent wrapping attacks
except Exception, ex:
tb = traceback.format_exc()
print tb
log.error(ex)
return None
return t
def _index_entity(self, e):
#log.debug("adding %s to index" % e.get('entityID'))
if 'ID' in e.attrib:
# Having removed the invalid entities this should now never happen...
schema().assertValid(t)
except DocumentInvalid, ex:
traceback.print_exc()
log.debug("schema validation failed on '%s': %s" % (base_url, _e(ex.error_log, m=base_url)))
raise MetadataException("schema validation failed")
except Exception, ex:
#log.debug(_e(schema().error_log))
log.error(ex)
if fail_on_error:
raise ex
return None
if key is not None:
try:
log.debug("verifying signature using %s" % key)
refs = xmlsec.verified(t, key)
if len(refs) != 1:
raise MetadataException("XML metadata contains %d signatures - exactly 1 is required" % len(refs))
t = refs[0] # prevent wrapping attacks
except Exception, ex:
tb = traceback.format_exc()
print tb
log.error(ex)
return None
return t
def _index_entity(self, e):
#log.debug("adding %s to index" % e.get('entityID'))
if 'ID' in e.attrib:
del e.attrib['ID']
