Lateral Movement

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Description

The adversary is trying to move through your ICS environment.

Lateral Movement consists of techniques that adversaries use to enter and control remote systems on a network. These techniques abuse default credentials, known accounts, and vulnerable services, and may also leverage dual-homed devices and systems that reside on both the IT and OT networks. The adversary uses these techniques to pivot to their next point in the environment, positioning themselves to where they want to be or think they should be. Following through on their primary objective often requires Discovery of the network and Collection to develop awareness of unique ICS devices and processes, in order to find their target and subsequently gain access to it. Reaching this objective often involves pivoting through multiple systems, devices, and accounts. Adversaries may install their own remote tools to accomplish Lateral Movement or leverage default tools, programs, and manufacturer set or other legitimate credentials native to the network, which may be stealthier.

Techniques in this Tactics Category

Below is a list of all the Lateral Movement techniques in ATT&CK for ICS:

NameTacticsTechnical Description
Default CredentialsLateral MovementAdversaries may leverage manufacturer or supplier set default credentials on control system devices. These default credentials may have administrative permissions and may be necessary for initial configuration of the device. It is general best practice to change the passwords for these accounts as soon as possible, but some manufacturers may have devices that have passwords or usernames that cannot be changed.1 Default credentials are normally documented in an instruction manual that is either packaged with the device, published online through official means, or published online through unofficial means. Adversaries may leverage default credentials that have not been properly modified or disabled.
Exploitation of Remote ServicesLateral MovementAdversaries may exploit a software vulnerability to take advantage of a programming error in a program, service, or within the operating system software or kernel itself to enable remote service abuse. A common goal for post-compromise exploitation of remote services is for lateral movement to enable access to a remote system.2 ICS asset owners and operators have been affected by ransomware (or disruptive malware masquerading as ransomware) migrating from enterprise IT to ICS environments: WannaCry, NotPetya, and BadRabbit. In each of these cases, self-propagating (“wormable”) malware initially infected IT networks, but through exploit (particularly the SMBv1-targeting MS17-010 vulnerability) spread to industrial networks, producing significant impacts.3
External Remote ServicesLateral Movement
Initial Access
Adversaries may leverage external remote services as a point of initial access into your network. These services allow users to connect to internal network resources from external locations. Examples are VPNs, Citrix, and other access mechanisms. Remote service gateways often manage connections and credential authentication for these services.4

External remote services allow administration of a control system from outside the system. Often, vendors and internal engineering groups have access to external remote services to control system networks via the corporate network. In some cases, this access is enabled directly from the internet. While remote access enables ease of maintenance when a control system is in a remote area, compromise of remote access solutions is a liability. The adversary may use these services to gain access to and execute attacks against a control system network. Access to valid accounts is often a requirement.

As they look for an entry point into the control system network, adversaries may begin searching for existing point‐to‐point VPN implementations at trusted third party networks or through remote support employee connections where split tunneling is enabled.5

In the Maroochy Attack, the adversary was able to gain remote computer access to the system over radio.

The 2015 attack on the Ukranian power grid showed the use of existing remote access tools within the environment to access the control system network. The adversary harvested worker credentials, some of them for VPNs the grid workers used to remotely log into the control system networks.6578 The VPNs into these networks appear to have lacked two‐factor authentication.5
Program Organization UnitsLateral Movement
Execution
Program Organizational Units (POUs) are block structures used within PLC programming to create programs and projects.9 POUs can be used to hold user programs written in IEC 61131-3 languages: Structured text, Instruction list, Function block, and Ladder logic.10 They can also provide additional functionality, such as establishing connections between the PLC and other devices using TCON.11

Stuxnet uses a simple code-prepending infection technique to infect Organization Blocks (OB). For example, the following sequence of actions is performed when OB1 is infected 12:

  • Increase the size of the original block.
  • Write malicious code to the beginning of the block.
  • Insert the original OB1 code after the malicious code.
Remote File CopyLateral MovementAdversaries may copy files from one system to another to stage adversary tools or other files over the course of an operation.13 Copying of files may also be performed laterally between internal victim systems to support Lateral Movement with remote Execution using inherent file sharing protocols such as file sharing over SMB to connected network shares.13 In control systems environments, malware may use SMB and other file sharing protocols to move laterally through industrial networks.
Valid AccountsPersistence
Lateral Movement
Adversaries may steal the credentials of a specific user or service account using credential access techniques. In some cases, default credentials for control system devices may be publicly available. Compromised credentials may be used to bypass access controls placed on various resources on hosts and within the network, and may even be used for persistent access to remote systems. Compromised and default credentials may also grant an adversary increased privilege to specific systems and devices or access to restricted areas of the network. Adversaries may choose not to use malware or tools, in conjunction with the legitimate access those credentials provide, to make it harder to detect their presence or to control devices and send legitimate commands in an unintended way.

Adversaries may also create accounts, sometimes using predefined account names and passwords, to provide a means of backup access for persistence.14

The overlap of credentials and permissions across a network of systems is of concern because the adversary may be able to pivot across accounts and systems to reach a high level of access (i.e., domain or enterprise administrator) and possibly between the enterprise and operational technology environments. Adversaries may be able to leverage valid credentials from one system to gain access to another system.

In the 2015 attack on the Ukranian power grid, the adversaries used valid credentials to interact directly with the client application of the distribution management system (DMS) server via a VPN and native remote access services to access employee workstations hosting HMI applications.5 The adversaries caused outages at three different energy companies, causing loss of power to over 225,000 customers over various areas.5

References