Upgraded SHA-1 key signatures from warnings to failures. Added deprecation warning to ssh-rsa-cert-v00@openssh.com, ssh-rsa-cert-v01@openssh.com, x509v3-sign-rsa, and x509v3-ssh-rsa host key types.

README.md

@@ -161,6 +161,8 @@ For convenience, a web front-end on top of the command-line tool is available at
 ### v2.4.0-dev (???)
  - Added multi-threaded scanning support.
  - Added version check for OpenSSH user enumeration (CVE-2018-15473).
+ - Added deprecation note to host key types based on SHA-1.
+ - Upgraded warnings to failures for host key types based on SHA-1.
  - Fixed crash when receiving unexpected response during host key test.
  - Fixed hang against older Cisco devices during host key test & gex test.
  - Fixed improper termination while scanning multiple targets when one target returns an error.

src/ssh_audit/hostkeytest.py

@@ -155,12 +155,20 @@ class HostKeyTest:
                     if (cert is False) and (hostkey_modulus_size < 2048):
                         for rsa_type in HostKeyTest.RSA_FAMILY:
                             alg_list = SSH2_KexDB.ALGORITHMS['key'][rsa_type]
-                            alg_list.append(['using small %d-bit modulus' % hostkey_modulus_size])
+
+                            # If no failure list exists, add an empty failure list.
+                            if len(alg_list) < 2:
+                                alg_list.append([])
+                            alg_list[1].append('using small %d-bit modulus' % hostkey_modulus_size)
                     elif (cert is True) and ((hostkey_modulus_size < 2048) or (ca_modulus_size > 0 and ca_modulus_size < 2048)):  # pylint: disable=chained-comparison
                         alg_list = SSH2_KexDB.ALGORITHMS['key'][host_key_type]
                         min_modulus = min(hostkey_modulus_size, ca_modulus_size)
                         min_modulus = min_modulus if min_modulus > 0 else max(hostkey_modulus_size, ca_modulus_size)
-                        alg_list.append(['using small %d-bit modulus' % min_modulus])
+
+                        # If no failure list exists, add an empty failure list.
+                        if len(alg_list) < 2:
+                            alg_list.append([])
+                        alg_list[1].append('using small %d-bit modulus' % min_modulus)
 
                 # If this host key type is in the RSA family, then mark them all as parsed (since results in one are valid for them all).
                 if host_key_type in HostKeyTest.RSA_FAMILY:

src/ssh_audit/ssh2_kexdb.py

@@ -37,7 +37,7 @@ class SSH2_KexDB:  # pylint: disable=too-few-public-methods
     FAIL_OPENSSH67_UNSAFE = 'removed (in server) since OpenSSH 6.7, unsafe algorithm'
     FAIL_OPENSSH61_REMOVE = 'removed since OpenSSH 6.1, removed from specification'
     FAIL_OPENSSH31_REMOVE = 'removed since OpenSSH 3.1'
-    INFO_OPENSSH82_FUTURE_DEPRECATION = 'A future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2'
+    INFO_OPENSSH82_FUTURE_DEPRECATION = 'a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2'
     FAIL_DBEAR67_DISABLED = 'disabled since Dropbear SSH 2015.67'
     FAIL_DBEAR53_DISABLED = 'disabled since Dropbear SSH 0.53'
     FAIL_DEPRECATED_CIPHER = 'deprecated cipher'
@@ -47,6 +47,7 @@ class SSH2_KexDB:  # pylint: disable=too-few-public-methods
     FAIL_DEPRECATED_MAC = 'deprecated MAC'
     FAIL_1024BIT_MODULUS = 'using small 1024-bit modulus'
     FAIL_UNPROVEN = 'using unproven algorithm'
+    FAIL_HASH_WEAK = 'using weak hashing algorithm'
     WARN_CURVES_WEAK = 'using weak elliptic curves'
     WARN_RNDSIG_KEY = 'using weak random number generator could reveal the key'
     WARN_HASH_WEAK = 'using weak hashing algorithm'
@@ -128,20 +129,20 @@ class SSH2_KexDB:  # pylint: disable=too-few-public-methods
             'rsa-sha2-512': [['7.2']],
             'ssh-ed25519': [['6.5,l10.7.0']],
             'ssh-ed25519-cert-v01@openssh.com': [['6.5']],
-            'ssh-rsa': [['2.5.0,d0.28,l10.2'], [WARN_HASH_WEAK], [], [INFO_OPENSSH82_FUTURE_DEPRECATION]],
+            'ssh-rsa': [['2.5.0,d0.28,l10.2'], [FAIL_HASH_WEAK], [], [INFO_OPENSSH82_FUTURE_DEPRECATION]],
             'ssh-dss': [['2.1.0,d0.28,l10.2', '6.9'], [FAIL_1024BIT_MODULUS, FAIL_OPENSSH70_WEAK], [WARN_RNDSIG_KEY]],
             'ecdsa-sha2-nistp256': [['5.7,d2013.62,l10.6.4'], [WARN_CURVES_WEAK], [WARN_RNDSIG_KEY]],
             'ecdsa-sha2-nistp384': [['5.7,d2013.62,l10.6.4'], [WARN_CURVES_WEAK], [WARN_RNDSIG_KEY]],
             'ecdsa-sha2-nistp521': [['5.7,d2013.62,l10.6.4'], [WARN_CURVES_WEAK], [WARN_RNDSIG_KEY]],
             'ecdsa-sha2-1.3.132.0.10': [[], [], [WARN_RNDSIG_KEY]],  # ECDSA over secp256k1 (i.e.: the Bitcoin curve)
             'x509v3-sign-dss': [[], [FAIL_1024BIT_MODULUS, FAIL_OPENSSH70_WEAK], [WARN_RNDSIG_KEY]],
-            'x509v3-sign-rsa': [[], [], [WARN_HASH_WEAK]],
+            'x509v3-sign-rsa': [[], [FAIL_HASH_WEAK], [], [INFO_OPENSSH82_FUTURE_DEPRECATION]],
             'x509v3-sign-rsa-sha256@ssh.com': [[]],
             'x509v3-ssh-dss': [[], [FAIL_1024BIT_MODULUS, FAIL_OPENSSH70_WEAK], [WARN_RNDSIG_KEY]],
-            'x509v3-ssh-rsa': [[], [], [WARN_HASH_WEAK]],
+            'x509v3-ssh-rsa': [[], [FAIL_HASH_WEAK], [], [INFO_OPENSSH82_FUTURE_DEPRECATION]],
-            'ssh-rsa-cert-v00@openssh.com': [['5.4', '6.9'], [FAIL_OPENSSH70_LEGACY], []],
+            'ssh-rsa-cert-v00@openssh.com': [['5.4', '6.9'], [FAIL_OPENSSH70_LEGACY, FAIL_HASH_WEAK], [], [INFO_OPENSSH82_FUTURE_DEPRECATION]],
             'ssh-dss-cert-v00@openssh.com': [['5.4', '6.9'], [FAIL_1024BIT_MODULUS, FAIL_OPENSSH70_LEGACY], [WARN_RNDSIG_KEY]],
-            'ssh-rsa-cert-v01@openssh.com': [['5.6'], [WARN_HASH_WEAK]],
+            'ssh-rsa-cert-v01@openssh.com': [['5.6'], [FAIL_HASH_WEAK], [], [INFO_OPENSSH82_FUTURE_DEPRECATION]],
             'ssh-dss-cert-v01@openssh.com': [['5.6', '6.9'], [FAIL_1024BIT_MODULUS, FAIL_OPENSSH70_WEAK], [WARN_RNDSIG_KEY]],
             'ecdsa-sha2-nistp256-cert-v01@openssh.com': [['5.7'], [WARN_CURVES_WEAK], [WARN_RNDSIG_KEY]],
             'ecdsa-sha2-nistp384-cert-v01@openssh.com': [['5.7'], [WARN_CURVES_WEAK], [WARN_RNDSIG_KEY]],

test/docker/expected_results/dropbear_2019.78_test1.txt

@@ -23,8 +23,9 @@
                                      `- [warn] using weak random number generator could reveal the key
                                      `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
 (key) ssh-rsa (1024-bit)             -- [fail] using weak hashing algorithm
-                                     `- [warn] using small 1024-bit modulus
+                                     `- [fail] using small 1024-bit modulus
                                      `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
+                                     `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 (key) ssh-dss                        -- [fail] using small 1024-bit modulus
                                      `- [fail] removed (in server) and disabled (in client) since OpenSSH 7.0, weak algorithm
                                      `- [warn] using weak random number generator could reveal the key

test/docker/expected_results/openssh_4.0p1_test1.txt

@@ -40,8 +40,9 @@
 
 # host-key algorithms
 (key) ssh-rsa (1024-bit)                  -- [fail] using weak hashing algorithm
-                                          `- [warn] using small 1024-bit modulus
+                                          `- [fail] using small 1024-bit modulus
                                           `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
+                                          `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 (key) ssh-dss                             -- [fail] using small 1024-bit modulus
                                           `- [fail] removed (in server) and disabled (in client) since OpenSSH 7.0, weak algorithm
                                           `- [warn] using weak random number generator could reveal the key

test/docker/expected_results/openssh_5.6p1_test1.txt

@@ -34,8 +34,9 @@
 
 # host-key algorithms
 (key) ssh-rsa (1024-bit)                    -- [fail] using weak hashing algorithm
-                                            `- [warn] using small 1024-bit modulus
+                                            `- [fail] using small 1024-bit modulus
                                             `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
+                                            `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 (key) ssh-dss                               -- [fail] using small 1024-bit modulus
                                             `- [fail] removed (in server) and disabled (in client) since OpenSSH 7.0, weak algorithm
                                             `- [warn] using weak random number generator could reveal the key

test/docker/expected_results/openssh_5.6p1_test2.txt

@@ -34,11 +34,13 @@
 
 # host-key algorithms
 (key) ssh-rsa (1024-bit)                    -- [fail] using weak hashing algorithm
-                                            `- [warn] using small 1024-bit modulus
+                                            `- [fail] using small 1024-bit modulus
                                             `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
+                                            `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 (key) ssh-rsa-cert-v01@openssh.com (1024-bit cert/1024-bit CA) -- [fail] using weak hashing algorithm
-                                                               `- [warn] using small 1024-bit modulus
+                                                               `- [fail] using small 1024-bit modulus
                                                                `- [info] available since OpenSSH 5.6
+                                                               `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 
 # encryption algorithms (ciphers)
 (enc) aes128-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52

test/docker/expected_results/openssh_5.6p1_test3.txt

@@ -34,11 +34,13 @@
 
 # host-key algorithms
 (key) ssh-rsa (1024-bit)                    -- [fail] using weak hashing algorithm
-                                            `- [warn] using small 1024-bit modulus
+                                            `- [fail] using small 1024-bit modulus
                                             `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
+                                            `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 (key) ssh-rsa-cert-v01@openssh.com (1024-bit cert/3072-bit CA) -- [fail] using weak hashing algorithm
-                                                               `- [warn] using small 1024-bit modulus
+                                                               `- [fail] using small 1024-bit modulus
                                                                `- [info] available since OpenSSH 5.6
+                                                               `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 
 # encryption algorithms (ciphers)
 (enc) aes128-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52

test/docker/expected_results/openssh_5.6p1_test4.txt

@@ -35,9 +35,11 @@
 # host-key algorithms
 (key) ssh-rsa (3072-bit)                    -- [fail] using weak hashing algorithm
                                             `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
+                                            `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 (key) ssh-rsa-cert-v01@openssh.com (3072-bit cert/1024-bit CA) -- [fail] using weak hashing algorithm
-                                                               `- [warn] using small 1024-bit modulus
+                                                               `- [fail] using small 1024-bit modulus
                                                                `- [info] available since OpenSSH 5.6
+                                                               `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 
 # encryption algorithms (ciphers)
 (enc) aes128-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52

test/docker/expected_results/openssh_5.6p1_test5.txt

@@ -35,8 +35,10 @@
 # host-key algorithms
 (key) ssh-rsa (3072-bit)                    -- [fail] using weak hashing algorithm
                                             `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
+                                            `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 (key) ssh-rsa-cert-v01@openssh.com (3072-bit cert/3072-bit CA) -- [fail] using weak hashing algorithm
                                                                `- [info] available since OpenSSH 5.6
+                                                               `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 
 # encryption algorithms (ciphers)
 (enc) aes128-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52

test/docker/expected_results/openssh_8.0p1_test1.txt

@@ -25,6 +25,7 @@
 (key) rsa-sha2-256 (3072-bit)               -- [info] available since OpenSSH 7.2
 (key) ssh-rsa (3072-bit)                    -- [fail] using weak hashing algorithm
                                             `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
+                                            `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
 (key) ecdsa-sha2-nistp256                   -- [fail] using weak elliptic curves
                                             `- [warn] using weak random number generator could reveal the key
                                             `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62

test/test_ssh2.py

@@ -147,7 +147,7 @@ class TestSSH2:
         self.audit(out, self._conf())
         out.write()
         lines = output_spy.flush()
-        assert len(lines) == 69
+        assert len(lines) == 70
 
     def test_ssh2_server_invalid_first_packet(self, output_spy, virtual_socket):
         vsocket = virtual_socket