A0016: Firewall

In an ICS environment, a firewall is often the control point that separates business IT from control system networks and enforces traffic between zones. Its value is not just blocking traffic; it is a dependency for operational resilience because many ATT&CK techniques target it as a path for access, discovery, remote administration, evasion, command and control, or disruption. Executives should treat firewall governance as both a security and continuity issue: if rules, remote access paths, credentials, or logging are weak, defenders may lose visibility into the boundary that is meant to limit adversary movement into industrial operations.

Executive priority

Prioritize evidence that ICS firewalls are intentionally segmented, governed by local security policy, monitored, and included in incident response planning. This asset is related to techniques involving public-facing application exploitation, external remote services, valid accounts, discovery, network sniffing, adversary-in-the-middle activity, denial of service, device restart/shutdown, and data destruction. That relationship context makes firewall control assurance relevant to business continuity, vendor/remote access risk, vulnerability prioritization, audit evidence, and cyber-physical risk management. Leaders should ask who owns rule approval, how emergency changes are reviewed, what remote access is permitted, whether logs are retained centrally, and whether operations can continue if the firewall becomes unavailable or misconfigured.

Technical view

For SOC, detection engineering, and IR teams, validate the firewall as a monitored ICS boundary asset across Embedded, Windows, Linux, and Network platforms where applicable. ATT&CK provides no official detection text for this asset, so coverage should be derived from its role and related techniques: command-line or GUI administration, external remote services, valid-account use, public-facing exposure, remote service exploitation, network discovery, port/broadcast/multicast discovery, standard application-layer protocols, network sniffing, adversary-in-the-middle conditions, evasion through exploitation, indicator removal, restart/shutdown, denial of service, and destructive activity. Confirm that firewall management events, rule changes, authentication events, interface status, traffic denies/allows, remote administration sessions, and anomalous protocol flows are available to investigators before an incident.

Likely telemetry

Firewall allow/deny traffic logs across ICS-to-business and inter-zone boundaries
Firewall rule, policy, NAT, route, and object change records
Administrator authentication, authorization, session, CLI, and GUI access logs
Remote access and external remote service connection records where the firewall participates in access control
System health telemetry such as interface state, CPU/memory, restart/shutdown events, and service availability

Detection direction

Baseline expected traffic between the business network, ICS network, and internal firewall zones; alert on new paths, unusual protocols, and unexpected ingress/egress patterns.
Monitor administrative access for unusual source locations, times, accounts, failed logons, successful privileged sessions, and changes made through CLI or GUI interfaces.
Tune discovery detections for port scanning, broadcast discovery, and multicast discovery with awareness that legitimate engineering, inventory, and monitoring tools may generate similar traffic.
Correlate firewall events with remote access, valid-account use, public-facing service exposure, and exploitation-related vulnerability evidence to improve triage value.
Watch for loss of visibility signals: logging disabled, configuration changes without approval, indicator removal behavior, unexpected restart/shutdown, interface flaps, or denial-of-service symptoms.

Mitigation priorities

Establish and document the firewall’s intended role as the ICS/business boundary and, where applicable, as an inter-zone control point.
Maintain least-privilege rule sets that allow only required communications between ICS, business, vendor, and management zones.
Restrict and monitor administrative access, including CLI, GUI, and remote service access; review default, shared, and privileged accounts.
Include firewall software, firmware, public-facing services, and remote access components in vulnerability and patch prioritization based on exposure and operational criticality.
Centralize logs, preserve configuration history, and test that logs remain available during incident response.

Additional notes and limits

This take is based on the ATT&CK ICS asset A0016 Firewall and the supplied relationships showing many ICS techniques targeting this asset. The object is an asset, not a technique, and ATT&CK lists no tactics and no official detection guidance. The most defensible use of this object is to drive control validation: segmentation, remote access governance, administrative monitoring, vulnerability exposure review, and IR readiness for a critical ICS boundary device.

ATT&CK does not provide official detection content for this asset, and the supplied relationships do not prove that any specific environment is exposed, compromised, or monitored. Local architecture, firewall product capabilities, rule sets, remote access design, logging configuration, and operational safety requirements are required to determine actual risk and coverage.

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Official MITRE ATT&CK definition

Firewall

A gateway that limits access between networks in accordance with local security policy.

In ICS networks, firewalls can exist in multiple locations in the network architecture and serve a variety of purposes. The first, and often the most important, is the firewall segmenting the ICS network from the business network. This firewall acts as the primary network boundary point that controls the ingress/egress of network traffic between the ICS and business networks. This firewall may also be a single device connected to multiple network segments, where the firewall defines individual zones for the different network segments and can control access to the zones and between the zones. This can limit the ability of an adversary to traverse a network.

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

How security teams should use this page

Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.

ATT&CK relationship table

Techniques used

This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.

Filter related techniques39 rows

Domain	ID	Name	Relationship / procedure
ICS	T0872	Indicator Removal on Host	Indicator Removal on Host targets this object.
ICS	T0871	Execution through API	Execution through API targets this object.
ICS	T1695.002	EthernetSub-technique	Ethernet targets this object.
ICS	T0822	External Remote Services	External Remote Services targets this object.
ICS	T0814	Denial of Service	Denial of Service targets this object.
ICS	T0809	Data Destruction	Data Destruction targets this object.
ICS	T0820	Exploitation for Evasion	Exploitation for Evasion targets this object.
ICS	T0842	Network Sniffing	Network Sniffing targets this object.
ICS	T0893	Data from Local System	Data from Local System targets this object.
ICS	T0883	Internet Accessible Device	Internet Accessible Device targets this object.
ICS	T0823	Graphical User Interface	Graphical User Interface targets this object.
ICS	T0830	Adversary-in-the-Middle	Adversary-in-the-Middle targets this object.
ICS	T0881	Service Stop	Service Stop targets this object.
ICS	T1693.001	System FirmwareSub-technique	System Firmware targets this object.
ICS	T1695.003	Wi-FiSub-technique	Wi-Fi targets this object.
ICS	T0840	Network Connection Enumeration	Network Connection Enumeration targets this object.
ICS	T0892	Change Credential	Change Credential targets this object.
ICS	T0846.003	Multicast DiscoverySub-technique	Multicast Discovery targets this object.
ICS	T0859	Valid Accounts	Valid Accounts targets this object.
ICS	T0853	Scripting	Scripting targets this object.
ICS	T0890	Exploitation for Privilege Escalation	Exploitation for Privilege Escalation targets this object.
ICS	T0866	Exploitation of Remote Services	Exploitation of Remote Services targets this object.
ICS	T0862	Supply Chain Compromise	Supply Chain Compromise targets this object.
ICS	T0846.002	Broadcast DiscoverySub-technique	Broadcast Discovery targets this object.
ICS	T0885	Commonly Used Port	Commonly Used Port targets this object.
ICS	T1694.001	Default CredentialsSub-technique	Default Credentials targets this object.
ICS	T0834	Native API	Native API targets this object.
ICS	T0819	Exploit Public-Facing Application	Exploit Public-Facing Application targets this object.
ICS	T0884	Connection Proxy	Connection Proxy targets this object.
ICS	T1694	Insecure Credentials	Insecure Credentials targets this object.
ICS	T0851	Rootkit	Rootkit targets this object.
ICS	T0816	Device Restart/Shutdown	Device Restart/Shutdown targets this object.
ICS	T0846.001	Port ScanSub-technique	Port Scan targets this object.
ICS	T0869	Standard Application Layer Protocol	Standard Application Layer Protocol targets this object.
ICS	T0807	Command-Line Interface	Command-Line Interface targets this object.
ICS	T1695	Block Communications	Block Communications targets this object.
ICS	T0874	Hooking	Hooking targets this object.
ICS	T0846	Remote System Discovery	Remote System Discovery targets this object.
ICS	T0888	Remote System Information Discovery	Remote System Information Discovery targets this object.

Relationship explorer

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Change history

Object version and sync metadata

The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates.

ATT&CK release: 19.1
Object version: 1.1
Created: Sep 24, 2025, 18:17 UTC (UTC+00:00)
Modified: May 12, 2026, 14:53 UTC (UTC+00:00)
Raw hash: 2f9e18f0e1ed9396...

Imported snapshots across ATT&CK releases(1)

Release	Bundle imported	Object version	Modified	Status	Raw hash
19.1	Jul 14, 2026, 09:14 UTC (UTC+00:00)	1.1	May 12, 2026, 14:53 UTC (UTC+00:00)	Current bundle	`2f9e18f0e1ed…`

Raw source

Mirrored ATT&CK source object

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Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

[1]
mitre-attackA0016
Open source URL

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