Update DNS resolution for socks proxies

Gemfile.lock

@@ -446,7 +446,8 @@ GEM
       metasm
       rex-core
       rex-text
-    rex-socket (0.1.57)
+    rex-socket (0.1.58)
+      dnsruby
       rex-core
     rex-sslscan (0.1.10)
       rex-core

lib/msf/core/opt.rb

@@ -35,8 +35,8 @@ def self.LPORT(default=nil, required=true, desc="The listen port")
     end
 
     # @return [OptString]
-    def self.Proxies(default=nil, required=false, desc="A proxy chain of format type:host:port[,type:host:port][...]")
-      Msf::OptString.new(__method__.to_s, [ required, desc, default ])
+    def self.Proxies(default=nil, required=false, desc="A proxy chain of format type:host:port[,type:host:port][...]. Supported proxies: #{Rex::Socket::Proxies.supported_types.join(', ')}")
+      Msf::OptProxies.new(__method__.to_s, [ required, desc, default ])
     end
 
     # @return [OptRhosts]

lib/msf/core/opt_address.rb

@@ -12,7 +12,7 @@ def type
     return 'address'
   end
 
-  def valid?(value, check_empty: true)
+  def valid?(value, check_empty: true, datastore: nil)
     return false if check_empty && empty_required_value?(value)
     return false unless value.kind_of?(String) or value.kind_of?(NilClass)
 

lib/msf/core/opt_address_local.rb

@@ -39,7 +39,7 @@ def normalize(value)
     sorted_addrs.any? ? sorted_addrs.first : ''
   end
 
-  def valid?(value, check_empty: true)
+  def valid?(value, check_empty: true, datastore: nil)
     return false if check_empty && empty_required_value?(value)
     return false unless value.kind_of?(String) || value.kind_of?(NilClass)
 

lib/msf/core/opt_address_range.rb

@@ -36,7 +36,7 @@ def normalize(value)
     return value
   end
 
-  def valid?(value, check_empty: true)
+  def valid?(value, check_empty: true, datastore: nil)
     return false if check_empty && empty_required_value?(value)
     return false unless value.kind_of?(String) or value.kind_of?(NilClass)
 

lib/msf/core/opt_address_routable.rb

@@ -9,7 +9,7 @@ module Msf
   ###
   class OptAddressRoutable < OptAddress
 
-    def valid?(value, check_empty: true)
+    def valid?(value, check_empty: true, datastore: nil)
       return false if Rex::Socket.is_ip_addr?(value) && Rex::Socket.addr_atoi(value) == 0
       super
     end

lib/msf/core/opt_base.rb

@@ -116,7 +116,7 @@ def validate_on_assignment?
     #
     # If it's required and the value is nil or empty, then it's not valid.
     #
-    def valid?(value, check_empty: true)
+    def valid?(value, check_empty: true, datastore: nil)
       if check_empty && required?
         # required variable not set
         return false if (value.nil? || value.to_s.empty?)

lib/msf/core/opt_bool.rb

@@ -16,7 +16,7 @@ def type
       return 'bool'
     end
 
-    def valid?(value, check_empty: true)
+    def valid?(value, check_empty: true, datastore: nil)
       return false if check_empty && empty_required_value?(value)
       return true if value.nil? && !required?
 

lib/msf/core/opt_enum.rb

@@ -17,7 +17,7 @@ def initialize(in_name, attrs = [],
       super
     end
 
-    def valid?(value = self.value, check_empty: true)
+    def valid?(value = self.value, check_empty: true, datastore: nil)
       return false if check_empty && empty_required_value?(value)
       return true if value.nil? && !required?
 

lib/msf/core/opt_float.rb

@@ -15,7 +15,7 @@ def normalize(value)
       Float(value) if value.present? && valid?(value)
     end
 
-    def valid?(value, check_empty: true)
+    def valid?(value, check_empty: true, datastore: nil)
       return false if check_empty && empty_required_value?(value)
       Float(value) rescue return false if value.present?
       super

lib/msf/core/opt_int.rb

@@ -19,7 +19,7 @@ def normalize(value)
       end
     end
 
-    def valid?(value, check_empty: true)
+    def valid?(value, check_empty: true, datastore: nil)
       return false if check_empty && empty_required_value?(value)
       return false if value.present? && !value.to_s.match(/^0x[0-9a-fA-F]+$|^-?\d+$/)
       super

lib/msf/core/opt_meterpreter_debug_logging.rb

@@ -19,7 +19,7 @@ def validate_on_assignment?
       true
     end
 
-    def valid?(value, check_empty: true)
+    def valid?(value, check_empty: true, datastore: nil)
       return false if !super(value, check_empty: check_empty)
 
       begin

lib/msf/core/opt_path.rb

@@ -21,7 +21,7 @@ def validate_on_assignment?
   end
 
   # Generally, 'value' should be a file that exists.
-  def valid?(value, check_empty: true)
+  def valid?(value, check_empty: true, datastore: nil)
     return false if check_empty && empty_required_value?(value)
     if value and !value.empty?
       if value =~ /^memory:\s*([0-9]+)/i

lib/msf/core/opt_port.rb

@@ -12,7 +12,7 @@ def type
     return 'port'
   end
 
-  def valid?(value, check_empty: true)
+  def valid?(value, check_empty: true, datastore: nil)
     port = normalize(value).to_i
     super && port <= 65535 && port >= 0
   end

lib/msf/core/opt_proxies.rb

@@ -0,0 +1,35 @@
+# -*- coding: binary -*-
+
+module Msf
+
+###
+#
+# Proxies option
+#
+###
+class OptProxies < OptBase
+
+  def type
+    'proxies'
+  end
+
+  def validate_on_assignment?
+    true
+  end
+
+  def normalize(value)
+    value
+  end
+
+  def valid?(value, check_empty: true, datastore: nil)
+    return false if check_empty && empty_required_value?(value)
+
+    parsed = Rex::Socket::Proxies.parse(value)
+    allowed_types = Rex::Socket::Proxies.supported_types
+    parsed.all? do |type, host, port|
+      allowed_types.include?(type) && host.present? && port.present?
+    end
+  end
+end
+
+end

lib/msf/core/opt_regexp.rb

@@ -12,7 +12,7 @@ def type
     return 'regexp'
   end
 
-  def valid?(value, check_empty: true)
+  def valid?(value, check_empty: true, datastore: nil)
     if check_empty && empty_required_value?(value)
       return false
     elsif value.nil?

lib/msf/core/opt_rhosts.rb

@@ -19,12 +19,13 @@ def normalize(value)
       value
     end
 
-    def valid?(value, check_empty: true)
+    def valid?(value, check_empty: true, datastore: nil)
       return false if check_empty && empty_required_value?(value)
       return false unless value.is_a?(String) || value.is_a?(NilClass)
 
-      if !value.nil? && value.empty? == false
-        return Msf::RhostsWalker.new(value).valid?
+      if !value.nil? && !value.empty?
+        rhost_walker = datastore ? Msf::RhostsWalker.new(value, datastore) : Msf::RhostsWalker.new(value)
+        return rhost_walker.valid?
       end
 
       super

lib/msf/core/opt_string.rb

@@ -34,7 +34,7 @@ def normalize(value)
     value
   end
 
-  def valid?(value=self.value, check_empty: true)
+  def valid?(value=self.value, check_empty: true, datastore: nil)
     value = normalize(value)
     return false if check_empty && empty_required_value?(value)
     return false if invalid_value_length?(value)

lib/msf/core/option_container.rb

@@ -197,7 +197,7 @@ def add_evasion_options(opts, owner = nil)
     def validate(datastore)
       # First mutate the datastore and normalize all valid values before validating permutations of RHOST/etc.
       each_pair do |name, option|
-        if option.valid?(datastore[name]) && (val = option.normalize(datastore[name])) != nil
+        if option.valid?(datastore[name], datastore: datastore) && (val = option.normalize(datastore[name])) != nil
           # This *will* result in a module that previously used the
           # global datastore to have its local datastore set, which
           # means that changing the global datastore and re-running
@@ -232,7 +232,7 @@ def validate(datastore)
 
         rhosts_walker.each do |datastore|
           each_pair do |name, option|
-            unless option.valid?(datastore[name])
+            unless option.valid?(datastore[name], datastore: datastore)
               error_options << name
               if rhosts_count > 1
                 error_reasons[name] << "for rhosts value #{datastore['UNPARSED_RHOSTS']}"
@@ -248,7 +248,7 @@ def validate(datastore)
       else
         error_options = []
         each_pair do |name, option|
-          unless option.valid?(datastore[name])
+          unless option.valid?(datastore[name], datastore: datastore)
             error_options << name
           end
         end

lib/msf/core/rhosts_walker.rb

@@ -50,6 +50,8 @@ class RhostResolveError < StandardError
       MESSAGE = 'Host resolution failed'
     end
 
+    # @param [String] value
+    # @param [Msf::DataStore] datastore
     def initialize(value = '', datastore = Msf::ModuleDataStore.new(nil))
       @value = value
       @datastore = datastore
@@ -141,30 +143,42 @@ def parse(value, datastore)
             schema = Regexp.last_match(:schema)
             raise InvalidSchemaError unless SUPPORTED_SCHEMAS.include?(schema)
 
-            found = false
             parse_method = "parse_#{schema}_uri"
             parsed_options = send(parse_method, value, datastore)
-            Rex::Socket::RangeWalker.new(parsed_options['RHOSTS']).each_ip do |ip|
-              results << datastore.merge(
-                parsed_options.merge('RHOSTS' => ip, 'UNPARSED_RHOSTS' => value)
-              )
-              found = true
-            end
-            unless found
-              raise RhostResolveError.new(value)
+            if perform_dns_resolution?(datastore)
+              found = false
+              Rex::Socket::RangeWalker.new(parsed_options['RHOSTS']).each_ip do |ip|
+                results << datastore.merge(
+                  parsed_options.merge('RHOSTS' => ip, 'UNPARSED_RHOSTS' => value)
+                )
+                found = true
+              end
+              unless found
+                raise RhostResolveError.new(value)
+              end
+            else
+              results << datastore.merge(parsed_options.merge('UNPARSED_RHOSTS' => value))
             end
           else
-            found = false
-            Rex::Socket::RangeWalker.new(value).each_host do |rhost|
+            if perform_dns_resolution?(datastore)
+              found = false
+              Rex::Socket::RangeWalker.new(value).each_host do |rhost|
+                overrides = {}
+                overrides['UNPARSED_RHOSTS'] = value
+                overrides['RHOSTS'] = rhost[:address]
+                set_hostname(datastore, overrides, rhost[:hostname])
+                results << datastore.merge(overrides)
+                found = true
+              end
+              unless found
+                raise RhostResolveError.new(value)
+              end
+            else
               overrides = {}
               overrides['UNPARSED_RHOSTS'] = value
-              overrides['RHOSTS'] = rhost[:address]
-              set_hostname(datastore, overrides, rhost[:hostname])
+              overrides['RHOSTS'] = value
+              set_hostname(datastore, overrides, value)
               results << datastore.merge(overrides)
-              found = true
-            end
-            unless found
-              raise RhostResolveError.new(value)
             end
           end
         rescue ::Interrupt
@@ -344,6 +358,14 @@ def parse_tcp_uri(value, datastore)
 
     protected
 
+    # @param [Msf::DataStore] datastore
+    # @return [Boolean] True if DNS resolution should be performed the RHOST values, false otherwise
+    def perform_dns_resolution?(datastore)
+      # If a socks proxy has been configured, don't perform DNS resolution - so that it instead happens via the proxy
+      # rex-socket does not currently support socks4a. SAPNI may need to be added to this list.
+      !(datastore['PROXIES'].to_s.include?(Rex::Socket::Proxies::ProxyType::HTTP) || datastore['PROXIES'].to_s.include?(Rex::Socket::Proxies::ProxyType::SOCKS5))
+    end
+
     def set_hostname(datastore, result, hostname)
       hostname = Rex::Socket.is_ip_addr?(hostname) ? nil : hostname
       result['RHOSTNAME'] = hostname if datastore['RHOSTNAME'].blank?

spec/lib/msf/core/opt_proxies_spec.rb

@@ -0,0 +1,27 @@
+# -*- coding:binary -*-
+
+require 'spec_helper'
+
+RSpec.describe Msf::OptProxies do
+
+  valid_values = [
+    nil,
+    '',
+    '            ',
+    'socks5:198.51.100.1:1080',
+    'socks4:198.51.100.1:1080',
+    'http:198.51.100.1:8080,socks4:198.51.100.1:1080',
+    'http:198.51.100.1:8080,       socks4:198.51.100.1:1080',
+    'sapni:198.51.100.1:8080,       socks4:198.51.100.1:1080',
+  ].map { |value| { value: value, normalized: value } }
+
+  invalid_values = [
+    { :value => 123 },
+    { :value => 'foo(' },
+    { :value => 'foo:198.51.100.1:8080' },
+    { :value => 'foo:198.51.100.18080' },
+    { :value => 'foo::' },
+  ]
+
+  it_behaves_like "an option", valid_values, invalid_values, 'proxies'
+end

spec/lib/msf/core/opt_spec.rb

@@ -33,7 +33,7 @@
 
     context 'Proxies' do
       subject { described_class::Proxies }
-      it { is_expected.to be_a(Msf::OptString) }
+      it { is_expected.to be_a(Msf::OptProxies) }
     end
 
     context 'RHOST' do
@@ -89,7 +89,7 @@
 
     context 'Proxies()' do
       subject { described_class::Proxies(default) }
-      it { is_expected.to be_a(Msf::OptString) }
+      it { is_expected.to be_a(Msf::OptProxies) }
       specify 'sets default' do
         expect(subject.default).to eq(default)
       end