ICS Persistence consists of techniques adversaries use to maintain access to ICS systems across restarts and operational changes. These include leveraging hardcoded credentials in ICS devices, modifying PLC programs, altering module firmware, and using valid accounts to maintain ongoing access to engineering workstations and control servers.
Tactic Overview
Tactic ID: TA0110 — Matrix: ICS — Techniques: 6
The Persistence tactic represents a phase in the adversary lifecycle where the adversary is trying to maintain their foothold in your ICS environment. This tactic is part of the MITRE ATT&CK ICS matrix and encompasses 6 known techniques that adversaries employ during this phase of an attack.
Understanding this tactic is critical for defenders to build effective detection strategies and implement appropriate countermeasures. Organizations should map their security controls against each technique to identify coverage gaps and prioritize defensive investments.
Techniques (6)
The following techniques are categorized under the Persistence tactic in the MITRE ATT&CK ICS matrix:
| Technique ID | Name | Description | MITRE Reference |
|---|---|---|---|
T0891 | Hardcoded Credentials | Adversaries exploit hardcoded credentials in ICS devices and firmware that cannot be changed by the operator. | T0891 |
T0889 | Modify Program | Adversaries modify PLC or controller programs to alter the control logic of physical processes. | T0889 |
T0839 | Module Firmware | Adversaries modify firmware of ICS modules (PLCs, I/O modules) to maintain persistence and manipulate processes. | T0839 |
T0873 | Project File Infection | Adversaries infect ICS project files (PLC programs) to spread malware when engineers open or download programs to controllers. | T0873 |
T0857 | System Firmware | Adversaries modify system firmware on ICS devices to maintain persistent access across device reboots. | T0857 |
T0859 | Valid Accounts | Adversaries use legitimate credentials to access ICS systems, often leveraging shared or default accounts common in OT environments. | T0859 |
Detection & Mitigation
Organizations should implement layered defenses addressing each technique within this tactic. Below are key mitigation strategies recommended by Mjolnir Security analysts.
Key Mitigations
- Change default credentials
- Firmware integrity monitoring
- Project file integrity checks
- Privileged account management
- Controller change management
Detection Strategies
Effective detection of Persistence techniques requires a combination of log analysis, behavioral monitoring, and threat intelligence correlation. Security teams should focus on establishing baselines for normal activity and alerting on deviations that may indicate adversary behavior aligned with this tactic.
- SIEM Integration: Correlate events across multiple data sources to detect technique patterns
- Behavioral Analytics: Deploy UEBA solutions to identify anomalous activity indicative of this tactic
- Threat Hunting: Proactively search for indicators of techniques within this tactic using hypothesis-driven investigations
- Purple Teaming: Regularly test detection coverage by simulating techniques from this tactic
Associated Threat Actors
The following threat actors are known to heavily leverage techniques from the Persistence tactic:
For comprehensive threat actor profiles, visit the APT Groups Hub.
Resources & References
Defend Against Persistence Techniques
Mjolnir Security provides expert threat intelligence, purple team exercises, and detection engineering services to help organizations defend against adversary tactics mapped to the MITRE ATT&CK framework.
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View All Reports →Written by Mjolnir Security Research — Published March 7, 2026