t0878-alarm-suppression

name	T0878_alarm-suppression
description	Adversaries may target protection function alarms to prevent them from notifying operators of critical conditions.
category	business-logic
version	18.1
author	cyberstrike-official
tags	["mitre-attack","ics","t0878","inhibit-response-function"]
technique_id	T0878
tactic	inhibit-response-function
all_tactics	["inhibit-response-function"]
platforms	["ICS"]
mitre_url	https://attack.mitre.org/techniques/T0878
tech_stack	["ics"]
cwe_ids	["CWE-400"]
chains_with	[]
prerequisites	[]
severity_boost	{}

T0878 Alarm Suppression

High-Level Description

Adversaries may target protection function alarms to prevent them from notifying operators of critical conditions. Alarm messages may be a part of an overall reporting system and of particular interest for adversaries. Disruption of the alarm system does not imply the disruption of the reporting system as a whole.

A Secura presentation on targeting OT notes a dual fold goal for adversaries attempting alarm suppression: prevent outgoing alarms from being raised and prevent incoming alarms from being responded to. The method of suppression may greatly depend on the type of alarm in question:

• An alarm raised by a protocol message
• An alarm signaled with I/O
• An alarm bit set in a flag (and read)

In ICS environments, the adversary may have to suppress or contend with multiple alarms and/or alarm propagation to achieve a specific goal to evade detection or prevent intended responses from occurring. Methods of suppression may involve tampering or altering device displays and logs, modifying in memory code to fixed values, or even tampering with assembly level instruction code.

Kill Chain Phase

• Inhibit Response Function (TA0107)

Platforms: ICS

What to Check

• Identify if Alarm Suppression technique is applicable to target ICS environment
• Check ICS/SCADA systems for indicators of Alarm Suppression
• Verify mitigations are bypassed or absent (4 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Identify Attack Surface

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

Assess Existing Defenses

Review whether mitigations for T0878 are in place. If defenses are absent or misconfigured, this technique may be exploitable in the ICS environment.

Remediation Guide

M0814 Static Network Configuration

Unauthorized connections can be prevented by statically defining the hosts and ports used for automation protocol connections.

M0807 Network Allowlists

Utilize network allowlists to restrict unnecessary connections to network devices (e.g., comm servers, serial to ethernet converters) and services, especially in cases when devices have limits on the number of simultaneous sessions they support.

M0930 Network Segmentation