Next, it performs a massive printf loop - the first stage. Since before the loop FreeConsole has been called all printf calls do basically nothing: This code has been directly copied from the documentation of printf: So what is the purpose of those numerous printf loops. As a result, the massive amount of calls delay the execution process and overload the sandbox with junk data. This behavior is called API Hammering. API Hammering is not a new technique, we have already seen it several years ago e.g. Joe Sandbox detects the API hammering successfully and rates it as malicious: Right after the printf flood, the sample performs another loop to delay execution by creating and writing to a temporary file - the second stage. In between it performs random sleeps: Again, the purpose is to overload the sandbox and delay the execution