mirror of https://github.com/jtesta/ssh-audit.git
Added allow_larger_keys flag to custom policies to control whether targets can have larger keys, and added Docker tests to complete work started in PR #242.
This commit is contained in:
Joe Testa
parent
20873db596
commit
9fae870260
|
|
@ -191,6 +191,7 @@ For convenience, a web front-end on top of the command-line tool is available at
|
|||
- Snap builds are now architecture-independent.
|
||||
- Changed Docker base image from `python:3-slim` to `python:3-alpine`, resulting in a 59% reduction in image size; credit [Daniel Thamdrup](https://github.com/dallemon).
|
||||
- Custom policies now support the `allow_algorithm_subset_and_reordering` directive to allow targets to pass with a subset and/or re-ordered list of host keys, kex, ciphers, and MACs. This allows for the creation of a baseline policy where targets can optionally implement stricter controls; partial credit [yannik1015](https://github.com/yannik1015).
|
||||
- Custom policies now support the `allow_larger_keys` directive to allow targets to pass with larger host keys, CA keys, and Diffie-Hellman keys. This allows for the creation of a baseline policy where targets can optionally implement stricter controls; partial credit [Damian Szuberski](https://github.com/szubersk).
|
||||
- Added 1 new key exchange algorithm: `gss-nistp384-sha384-*`.
|
||||
|
||||
### v3.1.0 (2023-12-20)
|
||||
|
|
|
|||
|
|
@ -790,6 +790,9 @@ run_custom_policy_test "config2" "test15" "${PROGRAM_RETVAL_GOOD}"
|
|||
# Failing test with algorithm subset matching.
|
||||
run_custom_policy_test "config2" "test16" "${PROGRAM_RETVAL_FAILURE}"
|
||||
|
||||
# Passing test with larger key matching.
|
||||
run_custom_policy_test "config2" "test17" "${PROGRAM_RETVAL_GOOD}"
|
||||
|
||||
# Failing test for built-in OpenSSH 8.0p1 server policy (RSA host key size is 3072 instead of 4096).
|
||||
run_builtin_policy_test "Hardened OpenSSH Server v8.0 (version 4)" "8.0p1" "test1" "-o HostKeyAlgorithms=rsa-sha2-512,rsa-sha2-256,ssh-ed25519 -o KexAlgorithms=curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha256 -o Ciphers=chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr -o MACs=hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,umac-128-etm@openssh.com" "${PROGRAM_RETVAL_FAILURE}"
|
||||
|
||||
|
|
|
|||
|
|
@ -55,6 +55,7 @@ class Policy:
|
|||
self._dh_modulus_sizes: Optional[Dict[str, int]] = None
|
||||
self._server_policy = True
|
||||
self._allow_algorithm_subset_and_reordering = False
|
||||
self._allow_larger_keys = False
|
||||
self._errors: List[Any] = []
|
||||
|
||||
self._name_and_version: str = ''
|
||||
|
|
@ -114,7 +115,7 @@ class Policy:
|
|||
key = key.strip()
|
||||
val = val.strip()
|
||||
|
||||
if key not in ['name', 'version', 'banner', 'compressions', 'host keys', 'optional host keys', 'key exchanges', 'ciphers', 'macs', 'client policy', 'host_key_sizes', 'dh_modulus_sizes', 'allow_algorithm_subset_and_reordering'] and not key.startswith('hostkey_size_') and not key.startswith('cakey_size_') and not key.startswith('dh_modulus_size_'):
|
||||
if key not in ['name', 'version', 'banner', 'compressions', 'host keys', 'optional host keys', 'key exchanges', 'ciphers', 'macs', 'client policy', 'host_key_sizes', 'dh_modulus_sizes', 'allow_algorithm_subset_and_reordering', 'allow_larger_keys'] and not key.startswith('hostkey_size_') and not key.startswith('cakey_size_') and not key.startswith('dh_modulus_size_'):
|
||||
raise ValueError("invalid field found in policy: %s" % line)
|
||||
|
||||
if key in ['name', 'banner']:
|
||||
|
|
@ -209,6 +210,8 @@ class Policy:
|
|||
self._server_policy = False
|
||||
elif key == 'allow_algorithm_subset_and_reordering' and val.lower() == 'true':
|
||||
self._allow_algorithm_subset_and_reordering = True
|
||||
elif key == 'allow_larger_keys' and val.lower() == 'true':
|
||||
self._allow_larger_keys = True
|
||||
|
||||
if self._name is None:
|
||||
raise ValueError('The policy does not have a name field.')
|
||||
|
|
@ -296,9 +299,12 @@ name = "Custom Policy (based on %s on %s)"
|
|||
# The version of this policy (displayed in the output during scans). Not parsed, and may be any value, including strings.
|
||||
version = 1
|
||||
|
||||
# When false, host keys, kex, ciphers, and MAC lists must match exactly. When true, the target host may support a subset of the specified algorithms and/or algorithms may appear in a different order; this is useful for specifying a baseline and allowing some hosts the option to implement stricter controls.
|
||||
# When false, host keys, kex, ciphers, and MAC lists must match exactly. When true, the target host may support a subset of the specified algorithms and/or algorithms may appear in a different order; this feature is useful for specifying a baseline and allowing some hosts the option to implement stricter controls.
|
||||
allow_algorithm_subset_and_reordering = false
|
||||
|
||||
# When false, host keys, CA keys, and Diffie-Hellman key sizes must exactly match what's specified in this policy. When true, target systems are allowed to have larger keys; this feature is useful for specifying a baseline and allowing some hosts the option to implement stricter controls.
|
||||
allow_larger_keys = false
|
||||
|
||||
# The banner that must match exactly. Commented out to ignore banners, since minor variability in the banner is sometimes normal.
|
||||
# banner = "%s"
|
||||
|
||||
|
|
@ -371,7 +377,8 @@ macs = %s
|
|||
server_host_keys = kex.host_keys()
|
||||
if hostkey_type in server_host_keys:
|
||||
actual_hostkey_size = cast(int, server_host_keys[hostkey_type]['hostkey_size'])
|
||||
if actual_hostkey_size < expected_hostkey_size:
|
||||
if (self._allow_larger_keys and actual_hostkey_size < expected_hostkey_size) or \
|
||||
(not self._allow_larger_keys and actual_hostkey_size != expected_hostkey_size):
|
||||
ret = False
|
||||
self._append_error('Host key (%s) sizes' % hostkey_type, [str(expected_hostkey_size)], None, [str(actual_hostkey_size)])
|
||||
|
||||
|
|
@ -387,7 +394,8 @@ macs = %s
|
|||
ret = False
|
||||
self._append_error('CA signature type', [expected_ca_key_type], None, [actual_ca_key_type])
|
||||
# Ensure that the actual and expected signature sizes match.
|
||||
elif actual_ca_key_size < expected_ca_key_size:
|
||||
elif (self._allow_larger_keys and actual_ca_key_size < expected_ca_key_size) or \
|
||||
(not self._allow_larger_keys and actual_ca_key_size != expected_ca_key_size):
|
||||
ret = False
|
||||
self._append_error('CA signature size (%s)' % actual_ca_key_type, [str(expected_ca_key_size)], None, [str(actual_ca_key_size)])
|
||||
|
||||
|
|
@ -446,7 +454,8 @@ macs = %s
|
|||
expected_dh_modulus_size = self._dh_modulus_sizes[dh_modulus_type]
|
||||
if dh_modulus_type in kex.dh_modulus_sizes():
|
||||
actual_dh_modulus_size = kex.dh_modulus_sizes()[dh_modulus_type]
|
||||
if expected_dh_modulus_size > actual_dh_modulus_size:
|
||||
if (self._allow_larger_keys and actual_dh_modulus_size < expected_dh_modulus_size) or \
|
||||
(not self._allow_larger_keys and actual_dh_modulus_size != expected_dh_modulus_size):
|
||||
ret = False
|
||||
self._append_error('Group exchange (%s) modulus sizes' % dh_modulus_type, [str(expected_dh_modulus_size)], None, [str(actual_dh_modulus_size)])
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,6 @@
|
|||
{
|
||||
"errors": [],
|
||||
"host": "localhost",
|
||||
"passed": true,
|
||||
"policy": "Docker policy: test17 (version 1)"
|
||||
}
|
||||
|
|
@ -0,0 +1,3 @@
|
|||
Host: localhost:2222
|
||||
Policy: Docker policy: test17 (version 1)
|
||||
Result: [0;32m✔ Passed[0m
|
||||
|
|
@ -0,0 +1,15 @@
|
|||
#
|
||||
# Docker policy: test17
|
||||
#
|
||||
|
||||
name = "Docker policy: test17"
|
||||
version = 1
|
||||
allow_larger_keys = true
|
||||
banner = "SSH-2.0-OpenSSH_8.0"
|
||||
compressions = none, zlib@openssh.com
|
||||
host keys = rsa-sha2-512, rsa-sha2-256, ssh-rsa, ecdsa-sha2-nistp256, ssh-ed25519
|
||||
key exchanges = curve25519-sha256, curve25519-sha256@libssh.org, ecdh-sha2-nistp256, ecdh-sha2-nistp384, ecdh-sha2-nistp521, diffie-hellman-group-exchange-sha256, diffie-hellman-group16-sha512, diffie-hellman-group18-sha512, diffie-hellman-group14-sha256, diffie-hellman-group14-sha1
|
||||
ciphers = chacha20-poly1305@openssh.com, aes128-ctr, aes192-ctr, aes256-ctr, aes128-gcm@openssh.com, aes256-gcm@openssh.com
|
||||
macs = umac-64-etm@openssh.com, umac-128-etm@openssh.com, hmac-sha2-256-etm@openssh.com, hmac-sha2-512-etm@openssh.com, hmac-sha1-etm@openssh.com, umac-64@openssh.com, umac-128@openssh.com, hmac-sha2-256, hmac-sha2-512, hmac-sha1
|
||||
host_key_sizes = {"ssh-rsa": {"hostkey_size": 2048}, "rsa-sha2-256": {"hostkey_size": 2048}, "rsa-sha2-512": {"hostkey_size": 2048}, "ssh-ed25519": {"hostkey_size": 256}}
|
||||
dh_modulus_sizes = {"diffie-hellman-group-exchange-sha256": 2048}
|
||||
|
|
@ -297,7 +297,7 @@ macs = mac_alg1, mac_alg2, mac_alg3'''
|
|||
pol_data = pol_data.replace(date.today().strftime('%Y/%m/%d'), '[todays date]')
|
||||
|
||||
# Instead of writing out the entire expected policy--line by line--just check that it has the expected hash.
|
||||
assert hashlib.sha256(pol_data.encode('ascii')).hexdigest() == '4b504b799f6b964a20ccbe8af7edd26c7b5f0e0b98070e754ea41dccdace33b4'
|
||||
assert hashlib.sha256(pol_data.encode('ascii')).hexdigest() == 'fb84bce442cff2bce9bf653d6373a8a938e3bfcfbd1e876f51a08c1842df3cff'
|
||||
|
||||
|
||||
def test_policy_evaluate_passing_1(self):
|
||||
|
|
|
|||
Loading…
Reference in New Issue