t0822-external-remote-services

name	T0822_external-remote-services
description	Adversaries may leverage external remote services as a point of initial access into your network.
category	input-validation
version	18.1
author	cyberstrike-official
tags	["mitre-attack","ics","t0822","initial-access"]
technique_id	T0822
tactic	initial-access
all_tactics	["initial-access"]
platforms	["ICS"]
mitre_url	https://attack.mitre.org/techniques/T0822
tech_stack	["ics"]
cwe_ids	["CWE-20"]
chains_with	[]
prerequisites	[]
severity_boost	{}

T0822 External Remote Services

High-Level Description

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.

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.

Kill Chain Phase

• Initial Access (TA0108)

Platforms: ICS

What to Check

• Identify if External Remote Services technique is applicable to target ICS environment
• Check ICS/SCADA systems for indicators of External Remote Services
• Verify mitigations are bypassed or absent (7 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Identify Attack Surface

Determine if the target ICS/SCADA environment is susceptible to External Remote Services by examining operational technology systems and network architecture.

Assess Existing Defenses

Review whether mitigations for T0822 are in place. If defenses are absent or misconfigured, this technique may be exploitable in the ICS environment.

Remediation Guide

M0930 Network Segmentation

Deny direct remote access to internal systems through the use of network proxies, gateways, and firewalls. Consider a jump server or host into the DMZ for greater access control. Leverage this DMZ or corporate resources for vendor access.

M0936 Account Use Policies

Configure features related to account use like login attempt lockouts, specific login times, and password strength requirements as examples. Consider these features as they relate to assets which may impact safety and availability.