Added IPv6 support for DHEat and connection rate tests. (#269)

README.md

@@ -215,6 +215,7 @@ For convenience, a web front-end on top of the command-line tool is available at
 
 ### v3.3.0-dev (???)
  - Added built-in policies for Ubuntu 24.04 LTS server and client.
+ - Added IPv6 support for DHEat and connection rate tests.
 
 ### v3.2.0 (2024-04-22)
  - Added implementation of the DHEat denial-of-service attack (see `--dheat` option; [CVE-2002-20001](https://nvd.nist.gov/vuln/detail/CVE-2002-20001)).

src/ssh_audit/dheat.py

@@ -160,6 +160,11 @@ class DHEat:
         # The SSH2_Kex object that we recieved from the server in a prior connection.  We'll use it as a template to craft our own kex.
         self.kex = kex
 
+        # Resolve the target to an IP address depending on the user preferences (IPv4 or IPv6).
+        self.debug("Resolving target %s..." % self.target)
+        self.target_address_family, self.target_ip_address = DHEat._resolve_hostname(self.target, aconf.ip_version_preference)
+        self.debug("Resolved %s to %s (address family %u)" % (self.target, self.target_ip_address, self.target_address_family))
+
         # The connection and read timeouts.
         self.connect_timeout = aconf.timeout
         self.read_timeout = aconf.timeout
@@ -324,6 +329,11 @@ class DHEat:
             print("\n%sUnfortunately, this feature is not currently functional under Windows.%s  This should get fixed in a future release.  See: <https://github.com/jtesta/ssh-audit/issues/261>" % (DHEat.YELLOWB, DHEat.CLEAR))
             return ""
 
+        # Resolve the target into an IP address
+        out.d("Resolving target %s..." % aconf.host)
+        target_address_family, target_ip_address = DHEat._resolve_hostname(aconf.host, aconf.ip_version_preference)
+        out.d("Resolved %s to %s (address family %u)" % (aconf.host, target_ip_address, target_address_family))
+
         spinner = ["-", "\\", "|", "/"]
         spinner_index = 0
 
@@ -349,7 +359,7 @@ class DHEat:
                 rate_str = " at a max rate of %s%u%s connections per second" % (DHEat.WHITEB, aconf.conn_rate_test_target_rate, DHEat.CLEAR)
 
             print()
-            print("Performing non-disruptive rate test against %s[%s]:%u%s with %s%u%s concurrent sockets%s.  No Diffie-Hellman requests will be sent." % (DHEat.WHITEB, aconf.host, aconf.port, DHEat.CLEAR, DHEat.WHITEB, concurrent_sockets, DHEat.CLEAR, rate_str))
+            print("Performing non-disruptive rate test against %s[%s]:%u%s with %s%u%s concurrent sockets%s.  No Diffie-Hellman requests will be sent." % (DHEat.WHITEB, target_ip_address, aconf.port, DHEat.CLEAR, DHEat.WHITEB, concurrent_sockets, DHEat.CLEAR, rate_str))
             print()
 
             # Make room for the multi-line output.
@@ -426,11 +436,11 @@ class DHEat:
 
             # Open new sockets until we've hit the number of concurrent sockets, or if we exceeded the number of maximum connections.
             while (len(socket_dict) < concurrent_sockets) and (len(socket_dict) + num_opened_connections < max_connections):
-                s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+                s = socket.socket(target_address_family, socket.SOCK_STREAM)
                 s.setblocking(False)
 
                 # out.d("Creating socket (%u of %u already exist)..." % (len(socket_dict), concurrent_sockets), write_now=True)
-                ret = s.connect_ex((aconf.host, aconf.port))
+                ret = s.connect_ex((target_ip_address, aconf.port))
                 num_attempted_connections += 1
                 if ret in [0, 115]:  # Check if connection is successful or EINPROGRESS.
                     socket_dict[s] = now
@@ -743,6 +753,22 @@ class DHEat:
         print()
 
 
+    @staticmethod
+    def _resolve_hostname(host: str, ip_version_preference: List[int]) -> Tuple[int, str]:
+        '''Resolves a hostname to its IPv4 or IPv6 address, depending on user preference.'''
+
+        family = socket.AF_UNSPEC
+        if len(ip_version_preference) == 1:
+            family = socket.AF_INET if ip_version_preference[0] == 4 else socket.AF_INET6
+
+        r = socket.getaddrinfo(host, 0, family, socket.SOCK_STREAM)
+        for address_family, socktype, _, _, addr in r:
+            if socktype == socket.SOCK_STREAM:
+                return address_family, addr[0]
+
+        return -1, ''
+
+
     def _run(self) -> bool:
         '''Where all the magic happens.'''
 
@@ -751,7 +777,7 @@ class DHEat:
         if sys.platform == "win32":
             self.output("%sWARNING:%s this feature has not been thoroughly tested on Windows.  It may perform worse than on UNIX OSes." % (self.YELLOWB, self.CLEAR))
 
-        self.output("Running DHEat test against %s[%s]:%u%s with %s%u%s concurrent sockets..." % (self.WHITEB, self.target, self.port, self.CLEAR, self.WHITEB, self.concurrent_connections, self.CLEAR))
+        self.output("Running DHEat test against %s[%s]:%u%s with %s%u%s concurrent sockets..." % (self.WHITEB, self.target_ip_address, self.port, self.CLEAR, self.WHITEB, self.concurrent_connections, self.CLEAR))
 
         # If the user didn't specify an exact kex algorithm to test, check our prioritized list against what the server supports.  Larger p-values (such as group18: 8192-bits) cause the most strain on the server.
         chosen_alg = ""
@@ -894,7 +920,8 @@ class DHEat:
 
         # Copy variables from the object (which might exist in another process?).  This might cut down on inter-process overhead.
         connect_timeout = self.connect_timeout
-        target = self.target
+        target_ip_address = self.target_ip_address
+        target_address_family = self.target_address_family
         port = self.port
 
         # Determine if we are attacking with a GEX.
@@ -945,17 +972,17 @@ class DHEat:
                 num_socket_exceptions = 0
                 num_openssh_throttled_connections = 0
 
-            s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            s = socket.socket(target_address_family, socket.SOCK_STREAM)
             s.settimeout(connect_timeout)
 
             # Loop until a successful TCP connection is made.
             connected = False
             while not connected:
 
-                # self.debug("Connecting to %s:%d" % (self.target, self.port))
+                # self.debug("Connecting to %s:%d" % (self.target_ip_address, self.port))
                 try:
                     num_attempted_tcp_connections += 1
-                    s.connect((target, port))
+                    s.connect((target_ip_address, port))
                     connected = True
                 except OSError as e:
                     self.debug("Failed to connect: %s" % str(e))

src/ssh_audit/ssh_audit.py

@@ -421,6 +421,8 @@ def output_recommendations(out: OutputBuffer, algs: Algorithms, algorithm_recomm
 
                         fn = level_to_output[level]
 
+                        an = '?'
+                        sg = '?'
                         if action == 'del':
                             an, sg = 'remove', '-'
                             ret = False