Persistence: RID Hijacking

In this post, we will be discussed on RID hijacking which is considered to be as a persistence technique in terms of cyber kill chain and in this article, you will learn multiple ways to perform RID hijacking.

Table of Content

Introduction

  • FSMO roles
  • SID & RID
  • Syntax
  • Important Key points

RID-Hijacking

  • Metasploit
  • Empire

Introduction

Microsoft divided the responsibilities of a DC into FSMO roles that together make a full AD system, FSMO (Flexible Single Master Operation) has 5 responsibilities for forest and domain.

  • Schema Master (one per forest)
  • Domain Naming Master (one per forest)
  • Relative identifier (RID) Master (one per domain)
  • Primary Domain Controller (PDC) Emulator (one per domain)
  • Infrastructure Master (one per domain)

SID & RID

The RID is a Relative Identifier which is the last part of SID (security identifier) and should be unique for a particular object within a domain. Each security principal has a unique SID that is issued by a security agent. The agent can be a Windows local system or domain. The agent generates the SID when the security principal is created. The SID can be represented as a character string or as a structure.

Syntax

Syntax: S-[Revision]-[IdentifierAuthority]-[SubAuthority0]-[SubAuthority1]-…-[SubAuthority[SubAuthorityCount]](-RID)

Eg: S-1-5-21-1543651058-3042185658-368006193-1001

Important Key points

  • The revision is always 1 for current NT versions.
  • When a new issuing authority is established under Windows (for example, a new computer is deployed or a domain is established), a SID with an arbitrary value of 5 is allocated as an identifier authority.
  • A constant value of 21 is used as a particular value for the root of this group of sub-authorities, and a 96-bit random number is generated and parcelled out to the three sub-authorities with each sub-authority having a 32-bit chunk.
  • If the new issuing authority under which this SID was developed is a domain, this SID is referred to as the “SID domain.”
  • Windows allocates RIDs starting at 1,000; RIDs that have a value of less than 1,000 are considered reserved and are used for special accounts.
  • For example, all Windows accounts with a RID of 500 are considered built-in administrator accounts in their respective issuing authorities.

RID Hijacking

‘RID Hijacking’ is a tactic for an adversary to persist inside the victim’s system by hijacking the RID the Administrator account for the Guest account, or another local account. Creating persistence in the victim’s system allows an adversary to establish a foothold, continuously regaining access that will be unseen to you and allow to hijacker to logon as an authorized account which adversary has hijacked.

Thus, for this, you need to have privilege account session as we have in the below image, to establish persistence access.

Rid-Hijacking: Metasploit

So, as you know, we had meterperter session with admin privilege and Metasploit provides a module to create persistence in a victim’s machine by hijacking RID of administrator user.

 This module will create an entry on the target by modifying some properties of an existing account. It will change the account attributes by setting a Relative Identifier (RID), which should be owned by one existing account on the destination machine. Taking advantage of some Windows Local Users Management integrity issues, this module will allow authenticating with one known account credentials (like GUEST account), and access with the privileges of another existing account (like ADMINISTRATOR account), even if the spoofed account is disabled.

Once you run the exploit, it will check the status of the guest account and, if it is found to be disabled, it will activate the account first and overwrite the RID value from 501 to 500, i.e. the RID value of the administrator account.

As you’ve seen in the above step, the guest’s RID is 500 and the password is 123, so we logged in as a guest to get the CMD with Administrator privilege on the target machine. Here we are going to use the impacket tool to get the CMD shell of the remote machine.

As you can observe that we have obtained CMD Shell as “nt authority /system” i.e CMD as an administrator account.

Rid-Hijacking: Empire

RID hijacking is also possible using empire, you need to clone it module from Github.

Once you are done with configuration, then launch the module to start the attack, this will initialise the just like Metasploit. First, identify the status of the guest account and then hijack RID =500 for guest user.

Again repeat the above step to connect CMD of victim’s machine assure that you should have a privilege shell.

Reference

https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-azod/ecc7dfba-77e1-4e03-ab99-114b349c7164

Author: Geet Madan is a Certified Ethical Hacker, Researcher and Technical Writer at Hacking Articles on Information SecurityContact here

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