Elevate from Admin to NT Authority\SYSTEM

Elevate from Admin to NT Authority\SYSTEM


The other day I gained Administrative access to a windows machine. While I was enumerating around, I had the urge to escalate to the most powerful account on a Windows local instance: NT Authority\SYSTEM.

I realized there weren't a lot of posts online about it. I figured I'd give the steps I did in order to accomplish this task.



64Base - Walkthrough




It's been a while since I've been able to work on a vulnhub image. I started looking at recent releases and came across 64base. This VM has a Star Wars theme which is always great. Plus, it was 3mrgnc3's first public VM so I had to check it out!



Protostar - stack4

This is my fifth post on the Protostar series hosted by Exploit Exercises

We start off with understanding what is being asked of us:


About

Stack4 takes a look at overwriting saved EIP and standard buffer overflows.
This level is at /opt/protostar/bin/stack4
Hints
  • A variety of introductory papers into buffer overflows may help.
  • gdb lets you do “run < input”
  • EIP is not directly after the end of buffer, compiler padding can also increase the size.

Source code



#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>

void win()
{
  printf("code flow successfully changed\n");
}

int main(int argc, char **argv)
{
  char buffer[64];

  gets(buffer);
}


Nebula - level08

This is my ninth post on the Nebula series hosted by Exploit Exercises

We start off with understanding what is being asked of us:

About

World readable files strike again. Check what that user was up to, and use it to log into flag08 account.
To do this level, log in as the level08 account with the password level08. Files for this level can be found in /home/flag08.

Source code

There is no source code available for this level


Protostar - stack3

This is my fourth post on the Protostar series hosted by Exploit Exercises

We start off with understanding what is being asked of us:

About

Stack3 looks at environment variables, and how they can be set, and overwriting function pointers stored on the stack (as a prelude to overwriting the saved EIP)
Hints
  • both gdb and objdump is your friend you determining where the win() function lies in memory.
This level is at /opt/protostar/bin/stack3

Source code



#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>

void win()
{
  printf("code flow successfully changed\n");
}

int main(int argc, char **argv)
{
  volatile int (*fp)();
  char buffer[64];

  fp = 0;

  gets(buffer);

  if(fp) {
      printf("calling function pointer, jumping to 0x%08x\n", fp);
      fp();
  }
}