Yes, this is the part you mean, right? > This process requires that the SO has the setuid permission flag set. so you don't just have to download a binary fil

Yes, this is the part you mean, right? > This process requires that the SO has the setuid permission flag set. so you don't just have to download a binary file and somehow set LD_PRELOAD for that user, you also have to set the SUID bit on that binary file, which by itself only root can do...