Add --json output option

README.md

@@ -33,6 +33,7 @@ usage: ssh-audit.py [-1246pbcnvlt] <host>
                                software config (use -p to change port;
                                use -t to change timeout)
    -n,  --no-colors        disable colors
+   -j,  --json             JSON output
    -v,  --verbose          verbose output
    -l,  --level=<level>    minimum output level (info|warn|fail)
    -t,  --timeout=<secs>   timeout (in seconds) for connection and reading

ssh-audit.py

@@ -25,7 +25,7 @@
    THE SOFTWARE.
 """
 from __future__ import print_function
-import base64, binascii, errno, hashlib, getopt, io, os, random, re, select, socket, struct, sys
+import base64, binascii, errno, hashlib, getopt, io, os, random, re, select, socket, struct, sys, json
 
 VERSION = 'v2.1.0-dev'
 SSH_HEADER = 'SSH-{0}-OpenSSH_8.0' # SSH software to impersonate
@@ -62,7 +62,7 @@ def usage(err=None):
 	uout.head('# {0} {1}, https://github.com/jtesta/ssh-audit\n'.format(p, VERSION))
 	if err is not None and len(err) > 0:
 		uout.fail('\n' + err)
-	uout.info('usage: {0} [-1246pbcnvlt] <host>\n'.format(p))
+	uout.info('usage: {0} [-1246pbcnjvlt] <host>\n'.format(p))
 	uout.info('   -h,  --help             print this help')
 	uout.info('   -1,  --ssh1             force ssh version 1 only')
 	uout.info('   -2,  --ssh2             force ssh version 2 only')
@@ -72,6 +72,7 @@ def usage(err=None):
 	uout.info('   -b,  --batch            batch output')
 	uout.info('   -c,  --client-audit     starts a server on port 2222 to audit client\n                               software config (use -p to change port;\n                               use -t to change timeout)')
 	uout.info('   -n,  --no-colors        disable colors')
+	uout.info('   -j,  --json             JSON output')
 	uout.info('   -v,  --verbose          verbose output')
 	uout.info('   -l,  --level=<level>    minimum output level (info|warn|fail)')
 	uout.info('   -t,  --timeout=<secs>   timeout (in seconds) for connection and reading\n                               (default: 5)')
@@ -90,6 +91,7 @@ class AuditConf(object):
 		self.batch = False
 		self.client_audit = False
 		self.colors = True
+		self.json = False
 		self.verbose = False
 		self.level = 'info'
 		self.ipvo = ()  # type: Sequence[int]
@@ -101,7 +103,7 @@ class AuditConf(object):
 	def __setattr__(self, name, value):
 		# type: (str, Union[str, int, bool, Sequence[int]]) -> None
 		valid = False
-		if name in ['ssh1', 'ssh2', 'batch', 'client_audit', 'colors', 'verbose', 'timeout_set']:
+		if name in ['ssh1', 'ssh2', 'batch', 'client_audit', 'colors', 'verbose', 'timeout_set', 'json']:
 			valid, value = True, True if bool(value) else False
 		elif name in ['ipv4', 'ipv6']:
 			valid = False
@@ -148,8 +150,8 @@ class AuditConf(object):
 		# pylint: disable=too-many-branches
 		aconf = cls()
 		try:
-			sopts = 'h1246p:bcnvl:t:'
+			sopts = 'h1246p:bcnjvl:t:'
-			lopts = ['help', 'ssh1', 'ssh2', 'ipv4', 'ipv6', 'port',
+			lopts = ['help', 'ssh1', 'ssh2', 'ipv4', 'ipv6', 'port', 'json',
 			         'batch', 'client-audit', 'no-colors', 'verbose', 'level=', 'timeout=']
 			opts, args = getopt.gnu_getopt(args, sopts, lopts)
 		except getopt.GetoptError as err:
@@ -176,6 +178,8 @@ class AuditConf(object):
 				aconf.client_audit = True
 			elif o in ('-n', '--no-colors'):
 				aconf.colors = False
+			elif o in ('-j', '--json'):
+				aconf.json = True
 			elif o in ('-v', '--verbose'):
 				aconf.verbose = True
 			elif o in ('-l', '--level'):
@@ -225,6 +229,7 @@ class Output(object):
 		self.batch = False
 		self.verbose = False
 		self.use_colors = True
+		self.json = False
 		self.__level = 0
 		self.__colsupport = 'colorama' in sys.modules or os.name == 'posix'
 	
@@ -3137,6 +3142,76 @@ class Utils(object):
 		except:  # pylint: disable=bare-except
 			return -1.0
 
+def build_struct(banner, kex=None, pkm=None):
+	res = {
+		"banner": {
+			"raw": str(banner),
+			"protocol": banner.protocol,
+			"software": banner.software,
+			"comments": banner.comments,
+		},
+	}
+	if kex is not None:
+		res['compression'] = kex.server.compression
+
+		res['kex'] = []
+		alg_sizes = kex.dh_modulus_sizes()
+		for algorithm in kex.kex_algorithms:
+			entry = {
+				'algorithm': algorithm,
+			}
+			if (alg_sizes is not None) and (algorithm in alg_sizes):
+				hostkey_size, ca_size = alg_sizes[algorithm]
+				entry['keysize'] = hostkey_size
+				if ca_size > 0:
+					entry['casize'] = ca_size
+			res['kex'].append(entry)
+
+		res['key'] = []
+		alg_sizes = kex.rsa_key_sizes()
+		for algorithm in kex.key_algorithms:
+			entry = {
+				'algorithm': algorithm,
+			}
+			if (alg_sizes is not None) and (algorithm in alg_sizes):
+				hostkey_size, ca_size = alg_sizes[algorithm]
+				entry['keysize'] = hostkey_size
+				if ca_size > 0:
+					entry['casize'] = ca_size
+			res['key'].append(entry)
+
+		res['enc'] = kex.server.encryption
+		res['mac'] = kex.server.mac
+		res['fingerprints'] = []
+		host_keys = kex.host_keys()
+		for host_key_type in host_keys:
+			if host_keys[host_key_type] is None:
+				continue
+
+			fp = SSH.Fingerprint(host_keys[host_key_type])
+
+			# Workaround for Python's order-indifference in dicts.  We might get a random RSA type (ssh-rsa, rsa-sha2-256, or rsa-sha2-512), so running the tool against the same server three times may give three different host key types here.  So if we have any RSA type, we will simply hard-code it to 'ssh-rsa'.
+			if host_key_type in SSH2.HostKeyTest.RSA_FAMILY:
+				host_key_type = 'ssh-rsa'
+
+			# Skip over certificate host types (or we would return invalid fingerprints).
+			if '-cert-' in host_key_type:
+				continue
+			entry = {
+				'type': host_key_type,
+				'fp': fp.sha256,
+			}
+			res['fingerprints'].append(entry)
+	else:
+		res['key'] = ['ssh-rsa1']
+		res['enc'] = pkm.supported_ciphers
+		res['aut'] = pkm.supported_authentications
+		res['fingerprints'] = [{
+			'type': 'ssh-rsa1',
+			'fp': SSH.Fingerprint(pkm.host_key_fingerprint_data).sha256,
+		}]
+
+	return res
 
 def audit(aconf, sshv=None):
 	# type: (AuditConf, Optional[int]) -> None
@@ -3189,12 +3264,18 @@ def audit(aconf, sshv=None):
 		sys.exit(1)
 	if sshv == 1:
 		pkm = SSH1.PublicKeyMessage.parse(payload)
+		if aconf.json:
+			print(json.dumps(build_struct(banner, pkm=pkm)))
+		else:
 			output(banner, header, pkm=pkm)
 	elif sshv == 2:
 		kex = SSH2.Kex.parse(payload)
 		if aconf.client_audit is False:
 			SSH2.HostKeyTest.run(s, kex)
 			SSH2.GEXTest.run(s, kex)
+		if aconf.json:
+			print(json.dumps(build_struct(banner, kex=kex)))
+		else:
                         output(banner, header, client_audit=aconf.client_audit, kex=kex)