Design a way to install "utility libraries" when performing local escalation

When running exploits on foreign machines, it's required to have a copy of metaxploit.so installed, maybe even crypto.so
There will be a point where we will need a standard way to handle downloading said library from a shared server
One design question is : what to do with said library afterwards?

1. Let it on the system
   Pros :

• Admins need to investigate the folders to find the file
• Allows several scripts to work without redownloading each time
  Cons :
• Need a sneaky place to store the lib (like the USER/Config folder?)
• Other hackers can steal the copy for themselves

2. Delete it after the script finished
   Pros :

• The filesystem is clean, so normal users won't notice anything strange afterwards
• We don't let a valuable file on random machines
  Cons :
• The delete operation generates an additional log, easily noticeable by the admins
• Scripts can't run in parallel with the same file