Updated notes on OpenSSH default key exchanges. (#258)

src/ssh_audit/ssh2_kexdb.py

@@ -62,7 +62,8 @@ class SSH2_KexDB:  # pylint: disable=too-few-public-methods
     WARN_TAG_SIZE_96 = 'using small 96-bit tag size'
 
     INFO_DEFAULT_OPENSSH_CIPHER = 'default cipher since OpenSSH 6.9'
-    INFO_DEFAULT_OPENSSH_KEX_64_TO_89 = 'default key exchange from OpenSSH 6.4 to 8.9'
+    INFO_DEFAULT_OPENSSH_KEX_65_TO_73 = 'default key exchange from OpenSSH 6.5 to 7.3'
+    INFO_DEFAULT_OPENSSH_KEX_74_TO_89 = 'default key exchange from OpenSSH 7.4 to 8.9'
     INFO_DEFAULT_OPENSSH_KEX_90 = 'default key exchange since OpenSSH 9.0'
     INFO_DEPRECATED_IN_OPENSSH88 = 'deprecated in OpenSSH 8.8: https://www.openssh.com/txt/release-8.8'
     INFO_DISABLED_IN_DBEAR67 = 'disabled in Dropbear SSH 2015.67'
@@ -82,8 +83,8 @@ class SSH2_KexDB:  # pylint: disable=too-few-public-methods
         # Format: 'algorithm_name': [['version_first_appeared_in'], [reason_for_failure1, reason_for_failure2, ...], [warning1, warning2, ...], [info1, info2, ...]]
         'kex': {
             'Curve25519SHA256': [[]],
-            'curve25519-sha256': [['7.4,d2018.76'], [], [], [INFO_DEFAULT_OPENSSH_KEX_64_TO_89]],
-            'curve25519-sha256@libssh.org': [['6.4,d2013.62,l10.6.0'], [], [], [INFO_DEFAULT_OPENSSH_KEX_64_TO_89]],
+            'curve25519-sha256': [['7.4,d2018.76'], [], [], [INFO_DEFAULT_OPENSSH_KEX_74_TO_89]],
+            'curve25519-sha256@libssh.org': [['6.4,d2013.62,l10.6.0'], [], [], [INFO_DEFAULT_OPENSSH_KEX_65_TO_73]],
             'curve448-sha512': [[]],
             'curve448-sha512@libssh.org': [[]],
             'diffie-hellman-group14-sha1': [['3.9,d0.53,l10.6.0'], [FAIL_SHA1], [WARN_2048BIT_MODULUS]],
@@ -223,7 +224,7 @@ class SSH2_KexDB:  # pylint: disable=too-few-public-methods
             'null': [[], [FAIL_PLAINTEXT]],
             'pgp-sign-dss': [[], [FAIL_1024BIT_MODULUS]],
             'pgp-sign-rsa': [[], [FAIL_1024BIT_MODULUS]],
-            'rsa-sha2-256': [['7.2']],
+            'rsa-sha2-256': [['7.2,d2020.79']],
             'rsa-sha2-256-cert-v01@openssh.com': [['7.8']],
             'rsa-sha2-512': [['7.2']],
             'rsa-sha2-512-cert-v01@openssh.com': [['7.8']],
@@ -242,7 +243,7 @@ class SSH2_KexDB:  # pylint: disable=too-few-public-methods
             'ssh-dss-sha256@ssh.com': [[], [FAIL_1024BIT_MODULUS]],
             'ssh-dss-sha384@ssh.com': [[], [FAIL_1024BIT_MODULUS]],
             'ssh-dss-sha512@ssh.com': [[], [FAIL_1024BIT_MODULUS]],
-            'ssh-ed25519': [['6.5,l10.7.0']],
+            'ssh-ed25519': [['6.5,d2020.79,l10.7.0']],
             'ssh-ed25519-cert-v01@openssh.com': [['6.5']],
             'ssh-ed448': [[]],
             'ssh-ed448-cert-v01@openssh.com': [[], [], [], [INFO_NEVER_IMPLEMENTED_IN_OPENSSH]],
@@ -335,7 +336,7 @@ class SSH2_KexDB:  # pylint: disable=too-few-public-methods
             'cast128-ecb': [[], [FAIL_CAST], [WARN_CIPHER_MODE]],
             'cast128-ofb': [[], [FAIL_CAST], [WARN_CIPHER_MODE]],
             'chacha20-poly1305': [[], [], [], [INFO_DEFAULT_OPENSSH_CIPHER]],
-            'chacha20-poly1305@openssh.com': [['6.5'], [], [], [INFO_DEFAULT_OPENSSH_CIPHER]],
+            'chacha20-poly1305@openssh.com': [['6.5,d2020.79'], [], [], [INFO_DEFAULT_OPENSSH_CIPHER]],
             'crypticore128@ssh.com': [[], [FAIL_UNPROVEN]],
             'des-cbc': [[], [FAIL_DES], [WARN_CIPHER_MODE, WARN_BLOCK_SIZE]],
             'des-cfb': [[], [FAIL_DES], [WARN_CIPHER_MODE, WARN_BLOCK_SIZE]],

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

@@ -96,7 +96,7 @@
             "algorithm": "curve25519-sha256",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 7.4 to 8.9",
                     "available since OpenSSH 7.4, Dropbear SSH 2018.76"
                 ]
             }
@@ -105,7 +105,7 @@
             "algorithm": "curve25519-sha256@libssh.org",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 6.5 to 7.3",
                     "available since OpenSSH 6.4, Dropbear SSH 2013.62"
                 ]
             }

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

@@ -6,9 +6,9 @@
 
 # key exchange algorithms
 (kex) curve25519-sha256              -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
-                                     `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                     `- [info] default key exchange from OpenSSH 7.4 to 8.9
 (kex) curve25519-sha256@libssh.org   -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
-                                     `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                     `- [info] default key exchange from OpenSSH 6.5 to 7.3
 (kex) ecdh-sha2-nistp521             -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                      `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
 (kex) ecdh-sha2-nistp384             -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency

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

@@ -40,7 +40,7 @@
             "notes": {
                 "info": [
                     "default cipher since OpenSSH 6.9",
-                    "available since OpenSSH 6.5"
+                    "available since OpenSSH 6.5, Dropbear SSH 2020.79"
                 ],
                 "warn": [
                     "vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation"
@@ -115,7 +115,7 @@
             "algorithm": "curve25519-sha256",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 7.4 to 8.9",
                     "available since OpenSSH 7.4, Dropbear SSH 2018.76"
                 ]
             }
@@ -124,7 +124,7 @@
             "algorithm": "curve25519-sha256@libssh.org",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 6.5 to 7.3",
                     "available since OpenSSH 6.4, Dropbear SSH 2013.62"
                 ]
             }
@@ -229,7 +229,7 @@
             "keysize": 3072,
             "notes": {
                 "info": [
-                    "available since OpenSSH 7.2"
+                    "available since OpenSSH 7.2, Dropbear SSH 2020.79"
                 ]
             }
         },
@@ -264,7 +264,7 @@
             "algorithm": "ssh-ed25519",
             "notes": {
                 "info": [
-                    "available since OpenSSH 6.5"
+                    "available since OpenSSH 6.5, Dropbear SSH 2020.79"
                 ]
             }
         }

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

@@ -1,7 +1,7 @@
 # general
 (gen) banner: SSH-2.0-OpenSSH_8.0
 (gen) software: OpenSSH 8.0
-(gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2018.76+
+(gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2020.79+
 (gen) compression: enabled (zlib@openssh.com)
 
 # security
@@ -12,9 +12,9 @@
 
 # key exchange algorithms
 (kex) curve25519-sha256                     -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
-                                            `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                            `- [info] default key exchange from OpenSSH 7.4 to 8.9
 (kex) curve25519-sha256@libssh.org          -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
-                                            `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                            `- [info] default key exchange from OpenSSH 6.5 to 7.3
 (kex) ecdh-sha2-nistp256                    -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                             `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
 (kex) ecdh-sha2-nistp384                    -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
@@ -33,18 +33,18 @@
 
 # host-key algorithms
 (key) rsa-sha2-512 (3072-bit)               -- [info] available since OpenSSH 7.2
-(key) rsa-sha2-256 (3072-bit)               -- [info] available since OpenSSH 7.2
+(key) rsa-sha2-256 (3072-bit)               -- [info] available since OpenSSH 7.2, Dropbear SSH 2020.79
 (key) ssh-rsa (3072-bit)                    -- [fail] using broken SHA-1 hash algorithm
                                             `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
                                             `- [info] deprecated in OpenSSH 8.8: https://www.openssh.com/txt/release-8.8
 (key) ecdsa-sha2-nistp256                   -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                             `- [warn] using weak random number generator could reveal the key
                                             `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
-(key) ssh-ed25519                           -- [info] available since OpenSSH 6.5
+(key) ssh-ed25519                           -- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79
 
 # encryption algorithms (ciphers)
 (enc) chacha20-poly1305@openssh.com         -- [warn] vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation
-                                            `- [info] available since OpenSSH 6.5
+                                            `- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79
                                             `- [info] default cipher since OpenSSH 6.9
 (enc) aes128-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
 (enc) aes192-ctr                            -- [info] available since OpenSSH 3.7

test/docker/expected_results/openssh_8.0p1_test2.json

@@ -40,7 +40,7 @@
             "notes": {
                 "info": [
                     "default cipher since OpenSSH 6.9",
-                    "available since OpenSSH 6.5"
+                    "available since OpenSSH 6.5, Dropbear SSH 2020.79"
                 ],
                 "warn": [
                     "vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation"
@@ -105,7 +105,7 @@
             "algorithm": "curve25519-sha256",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 7.4 to 8.9",
                     "available since OpenSSH 7.4, Dropbear SSH 2018.76"
                 ]
             }
@@ -114,7 +114,7 @@
             "algorithm": "curve25519-sha256@libssh.org",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 6.5 to 7.3",
                     "available since OpenSSH 6.4, Dropbear SSH 2013.62"
                 ]
             }
@@ -209,7 +209,7 @@
             "algorithm": "ssh-ed25519",
             "notes": {
                 "info": [
-                    "available since OpenSSH 6.5"
+                    "available since OpenSSH 6.5, Dropbear SSH 2020.79"
                 ]
             }
         },

test/docker/expected_results/openssh_8.0p1_test2.txt

@@ -1,7 +1,7 @@
 # general
 (gen) banner: SSH-2.0-OpenSSH_8.0
 (gen) software: OpenSSH 8.0
-(gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2018.76+
+(gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2020.79+
 (gen) compression: enabled (zlib@openssh.com)
 
 # security
@@ -12,9 +12,9 @@
 
 # key exchange algorithms
 (kex) curve25519-sha256                     -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
-                                            `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                            `- [info] default key exchange from OpenSSH 7.4 to 8.9
 (kex) curve25519-sha256@libssh.org          -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
-                                            `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                            `- [info] default key exchange from OpenSSH 6.5 to 7.3
 (kex) ecdh-sha2-nistp256                    -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                             `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
 (kex) ecdh-sha2-nistp384                    -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
@@ -32,12 +32,12 @@
                                             `- [info] available since OpenSSH 3.9, Dropbear SSH 0.53
 
 # host-key algorithms
-(key) ssh-ed25519                           -- [info] available since OpenSSH 6.5
+(key) ssh-ed25519                           -- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79
 (key) ssh-ed25519-cert-v01@openssh.com (256-bit cert/256-bit ssh-ed25519 CA) -- [info] available since OpenSSH 6.5
 
 # encryption algorithms (ciphers)
 (enc) chacha20-poly1305@openssh.com         -- [warn] vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation
-                                            `- [info] available since OpenSSH 6.5
+                                            `- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79
                                             `- [info] default cipher since OpenSSH 6.9
 (enc) aes128-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
 (enc) aes192-ctr                            -- [info] available since OpenSSH 3.7

test/docker/expected_results/openssh_8.0p1_test3.json

@@ -40,7 +40,7 @@
             "notes": {
                 "info": [
                     "default cipher since OpenSSH 6.9",
-                    "available since OpenSSH 6.5"
+                    "available since OpenSSH 6.5, Dropbear SSH 2020.79"
                 ],
                 "warn": [
                     "vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation"
@@ -105,7 +105,7 @@
             "algorithm": "curve25519-sha256",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 7.4 to 8.9",
                     "available since OpenSSH 7.4, Dropbear SSH 2018.76"
                 ]
             }
@@ -114,7 +114,7 @@
             "algorithm": "curve25519-sha256@libssh.org",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 6.5 to 7.3",
                     "available since OpenSSH 6.4, Dropbear SSH 2013.62"
                 ]
             }
@@ -135,7 +135,7 @@
             "algorithm": "ssh-ed25519",
             "notes": {
                 "info": [
-                    "available since OpenSSH 6.5"
+                    "available since OpenSSH 6.5, Dropbear SSH 2020.79"
                 ]
             }
         }

test/docker/expected_results/openssh_8.0p1_test3.txt

@@ -1,7 +1,7 @@
 # general
 (gen) banner: SSH-2.0-OpenSSH_8.0
 (gen) software: OpenSSH 8.0
-(gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2018.76+
+(gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2020.79+
 (gen) compression: enabled (zlib@openssh.com)
 
 # security
@@ -12,18 +12,18 @@
 
 # key exchange algorithms
 (kex) curve25519-sha256                     -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
-                                            `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                            `- [info] default key exchange from OpenSSH 7.4 to 8.9
 (kex) curve25519-sha256@libssh.org          -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
-                                            `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                            `- [info] default key exchange from OpenSSH 6.5 to 7.3
 (kex) diffie-hellman-group-exchange-sha256 (4096-bit) -- [info] available since OpenSSH 4.4
                                                       `- [info] OpenSSH's GEX fallback mechanism was triggered during testing. Very old SSH clients will still be able to create connections using a 2048-bit modulus, though modern clients will use 4096. This can only be disabled by recompiling the code (see https://github.com/openssh/openssh-portable/blob/V_9_4/dh.c#L477).
 
 # host-key algorithms
-(key) ssh-ed25519                           -- [info] available since OpenSSH 6.5
+(key) ssh-ed25519                           -- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79
 
 # encryption algorithms (ciphers)
 (enc) chacha20-poly1305@openssh.com         -- [warn] vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation
-                                            `- [info] available since OpenSSH 6.5
+                                            `- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79
                                             `- [info] default cipher since OpenSSH 6.9
 (enc) aes256-gcm@openssh.com                -- [info] available since OpenSSH 6.2
 (enc) aes128-gcm@openssh.com                -- [info] available since OpenSSH 6.2

test/docker/expected_results/tinyssh_20190101_test1.json

@@ -18,7 +18,7 @@
             "notes": {
                 "info": [
                     "default cipher since OpenSSH 6.9",
-                    "available since OpenSSH 6.5"
+                    "available since OpenSSH 6.5, Dropbear SSH 2020.79"
                 ],
                 "warn": [
                     "vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation"
@@ -43,7 +43,7 @@
             "algorithm": "curve25519-sha256",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 7.4 to 8.9",
                     "available since OpenSSH 7.4, Dropbear SSH 2018.76"
                 ]
             }
@@ -52,7 +52,7 @@
             "algorithm": "curve25519-sha256@libssh.org",
             "notes": {
                 "info": [
-                    "default key exchange from OpenSSH 6.4 to 8.9",
+                    "default key exchange from OpenSSH 6.5 to 7.3",
                     "available since OpenSSH 6.4, Dropbear SSH 2013.62"
                 ]
             }
@@ -75,7 +75,7 @@
             "algorithm": "ssh-ed25519",
             "notes": {
                 "info": [
-                    "available since OpenSSH 6.5"
+                    "available since OpenSSH 6.5, Dropbear SSH 2020.79"
                 ]
             }
         }

test/docker/expected_results/tinyssh_20190101_test1.txt

@@ -1,23 +1,23 @@
 # general
 (gen) software: TinySSH noversion
-(gen) compatibility: OpenSSH 8.0-8.4, Dropbear SSH 2018.76+
+(gen) compatibility: OpenSSH 8.0-8.4, Dropbear SSH 2020.79+
 (gen) compression: disabled
 
 # key exchange algorithms
 (kex) curve25519-sha256                       -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
-                                              `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                              `- [info] default key exchange from OpenSSH 7.4 to 8.9
 (kex) curve25519-sha256@libssh.org            -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
-                                              `- [info] default key exchange from OpenSSH 6.4 to 8.9
+                                              `- [info] default key exchange from OpenSSH 6.5 to 7.3
 (kex) sntrup4591761x25519-sha512@tinyssh.org  -- [warn] using experimental algorithm
                                               `- [info] available since OpenSSH 8.0
                                               `- [info] the sntrup4591761 algorithm was withdrawn, as it may not provide strong post-quantum security
 
 # host-key algorithms
-(key) ssh-ed25519                             -- [info] available since OpenSSH 6.5
+(key) ssh-ed25519                             -- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79
 
 # encryption algorithms (ciphers)
 (enc) chacha20-poly1305@openssh.com           -- [warn] vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation
-                                              `- [info] available since OpenSSH 6.5
+                                              `- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79
                                               `- [info] default cipher since OpenSSH 6.9
 
 # message authentication code algorithms