15.2. Threat Model¶
The GEISA threat model identifies the assets requiring protection, the trust boundaries across which the GEISA Common Operating Environment (COE) operates, and representative threat scenarios that conformant implementations should be designed to mitigate. It is not exhaustive and is intended to be a living framework that evolves alongside the threat landscape. It provides implementers with a baseline set of threats to consider when evaluating their specific implementations.
Implementers SHOULD extend this model to reflect their operational context, inclusive of, but not limited to, their deployment, regulatory, and operational environments and identify additional threats applicable to their specific circumstances.
Unlike traditional IT systems, compromise of grid-edge devices and resources may create direct reliability impacts to the electrical grid or to individual service locations. Therefore, prioritizing a defense-in-depth approach is essential. Additionally, the potential for physical access to grid-edge devices creates a need for robust physical security controls and/or tamper resistance.
The GEISA specification is designed to enable implementers to meet these needs through the design of the COE and the control levers it provides to enforce deployment-specific security policy.
15.2.2. Lifecycle Trust Enforcement¶
Trust within GEISA is not established at a single point in time. It is evaluated and enforced across multiple lifecycle transitions, including application ingest, approval, deployment, installation, activation, and execution.
Conformant implementations must ensure that trust assertions made by one system or phase are independently verified at the point where enforcement occurs. Trust shall not be implicitly inherited across lifecycle boundaries without validation.
This includes, but is not limited to:
Verification of application integrity and publisher identity when software is introduced into lifecycle management systems (i.e. a GEISA ADM conformant Edge Management System).
Confirmation of operator authorization prior to deployment to a device or environment.
Independent validation performed by the COE prior to installation and at activation (including restarts of applications and/or workloads).
Note
Need to discuss execution/runtime or periodic validations.
Continued enforcement of policy, identity, and behavioral constraints during runtime operation.
Runtime enforcement of operator-defined behavioral constraints, including the ability to detect, limit, or terminate workloads that violate policy or exceed authorized resource or communication profiles.
Revocation of trust relationships when software is no longer authorized for execution within the COE (e.g. due to compromise, policy change, or end of life).
This model ensures that compromise of any single lifecycle component does not result in implicit trust of software or actions elsewhere in the system and helps to mitigate risks resulting in systemic compromise.
15.2.3. Trust Revocation and Credential Lifecycle¶
GEISA defines mechanisms (revocation, update, policy change), but the System Operator is responsible for monitoring, initiating, and governing these actions, though some may be automated in vendor implementations. GEISA implementations and deployments must support the ability to modify or withdraw previously established trust relationships throughout the operational lifecycle of a device or application.
Conformant implementations shall provide mechanisms enabling:
Revocation or invalidation of application, publisher, operator, or device credentials when trust can no longer be assured.
Enforcement of operator-directed actions to disable, restrict, or remove software that is no longer authorized for execution within the COE.
Update and rotation of trust anchors, certificates, and associated cryptographic material without requiring replacement of deployed devices.
Local enforcement of revocation or policy changes even in environments with limited or intermittent connectivity to centralized management systems.
These capabilities ensure that trust established during provisioning or deployment can be continuously evaluated and adjusted in response to evolving security conditions, operational decisions, or cryptographic requirements.
15.2.4. Assets Requiring Protection¶
The GEISA specification is designed to protect the following asset classes:
Integrity of grid-impacting control functions (e.g., service disconnect, DER coordination, or other local controls)
Authenticity and integrity of telemetry, metrology, and status data
Device identity and associated cryptographic credentials
Availability of edge execution environments necessary for safe grid operation
Application and Application Publisher identity as represented by associated credentials
Isolation between workloads executing within the COE
Application and device monitoring, behavioral logging, and alerting capabilities
Customer data subject to privacy and/or regulatory protection
Trust relationships with utility/operator systems
Software and firmware integrity across the device lifecycle
15.2.5. Trust Boundaries and External Interfaces¶
The GEISA Execution Environment operates across multiple security trust boundaries. A trust boundary exists wherever administrative control, execution privilege, or assurance level changes.
GEISA defines these boundaries to enable secure interoperability among heterogeneous vendor solutions while preserving the operator’s ability to enforce deployment-specific policy. The GEISA Common Operating Environment (COE) acts as the on-device enforcement point through which operators may permit, restrict, or condition interactions between applications, networks, and connected systems.
These enforcement functions exist regardless of whether applications execute locally, participate in hybrid edge/cloud workflows, or are installed through centralized lifecycle management systems.
All interactions crossing these boundaries shall be treated as untrusted unless explicitly authenticated, authorized, and governed by operator-defined policy. The boundaries listed below represent the primary attack surfaces considered by this model. They are not exhaustive. Implementers shall evaluate their deployment to determine whether additional boundaries are present.
Note that examples are illustrative and do not define required sensor types or configurations.
Boundary |
Description |
Examples |
|---|---|---|
Field Devices |
Physically accessible deployment environment where attackers may gain hardware access. This includes attempts to tamper with the device, extract sensitive material, or conduct side-channel to observe, influence, or bypass normal system protections. |
Enclosure access, debug ports |
Local Provisioning / Maintenance |
Interfaces used during installation or maintenance that may introduce temporary elevated trust. |
Field tools, Bluetooth, serial |
Sensors |
Data originating from instrumentation whose acquisition and integrity are governed by the COE device itself. |
Metrology, temperature, accelerometer, GNSS, other directly-attached sensors |
Customer Networks |
Communications over networks not managed by the utility/operator and therefore not inherently trusted. |
Home/Business Wi-Fi, HAN, LAN, Thread |
Workload (e.g. Applications) |
Separation between the COE platform and hosted workloads enabling operator control over resource and network access. This boundary exists even when all code is local due to multi-tenancy, privilege separation, and differing lifecycles. |
GEISA COE APIs, resource allocation, storage, permission models |
External Device / Control |
Interfaces to autonomous systems not governed by GEISA lifecycle or assurance controls. Includes third-party devices or subsystems that may have grid or local impact if compromised. |
Inverters, Matter devices, thermostats, gateways, controllable loads, local data sources |
Operational Integration |
Exchange of operational data with upstream systems, including utility or non-utility infrastructure outside the COE trust domain. |
AMI backhaul, DERMS, analytics platforms, monitoring systems, hybrid edge/cloud applications |
Lifecycle Management |
Authority to deploy, configure, approve, restrict, update, or revoke software and policy governing the COE. |
Application deployment, update orchestration, policy/config distribution |
Utility-operated networks and systems are considered external to the COE trust domain and are therefore modeled within the Operational Integration or Lifecycle Management boundaries depending on function.
Devices communicating via customer-managed ecosystems (e.g., Wi-Fi, Thread, Matter, or similar technologies) are not considered part of the Sensor Boundary, even when providing measurement data. Such devices operate with independent identity, firmware, and lifecycle control and are therefore treated as External Devices whose communications traverse the Customer Network Boundary.
15.2.6. Threat Actors Considered¶
The GEISA threat model considers a range of potential threat actors with varying levels of access, capability, and intent. These actors may operate independently or in coordination and may target individual devices, aggregated infrastructure, or upstream systems.
The following categories are considered within scope:
Threat Actor |
Description |
|---|---|
Supply Chain Adversary |
Actor seeking to introduce malicious components, firmware, or updates during manufacturing or distribution stages. |
Field-Level Physical Attacker |
Actor with physical access capable of tampering, extraction, or hardware manipulation to disrupt operation, alter executable code outside authorized lifecycle processes, or obtain data from the device. This may include invasive techniques (e.g., device/chip decapsulation (“decap”), probing, or unauthorized reflashing) intended to bypass protections. |
Opportunistic Local Network Attacker |
Actor on a customer or shared network capable of interception, manipulation, or disruption of communications or operations. |
Unauthorized Local Service Actor |
Individual attempting access via provisioning or maintenance interfaces using unauthorized or stolen tools or credentials. |
Remote Adversary |
External attacker using network access to exploit exposed services, protocols, or integrations. |
Coordinated Distributed Actor |
Group or automated campaign capable of influencing behavior across many endpoints. |
Compromised Upstream System |
Trusted operational or management system issuing valid-looking but malicious actions after being compromised. |
Compromised External Device |
Third-party or customer-managed device providing malicious data or attempting lateral influence on the COE. |
Malicious or Negligent Insider |
Individual with authorized access who may misuse privileges, attempt escalation, alter policy, or exfiltrate information, either intentionally or unintentionally. |
15.2.7. Representative Threat Scenarios¶
The following scenarios illustrate representative ways in which identified threat actors may attempt to exploit trust boundaries to impact protected assets. These examples are not exhaustive but demonstrate the types of risks implementations should be designed to address.
Implementations SHOULD address these risks using deployment-specific controls, policies, and technologies consistent with the capabilities defined by the GEISA specification.
15.2.9. Compromise of a Customer-Network Connected Device¶
A Compromised External Device (e.g., Matter or Wi-Fi system) provides falsified telemetry or malformed data intended to influence processing performed locally or by upstream systems participating in hybrid workflows.
Boundaries Involved: External Device / Control, Customer Networks
Potential Impact: Corrupted data, unintended control actions, incorrect operational conclusions, or propagation of misleading information into coordinated services.
15.2.10. Malicious or Altered Software Introduced During Update¶
A Supply Chain Adversary inserts malicious code into firmware, applications, or update packages prior to deployment.
Boundaries Involved: Lifecycle Management
Potential Impact: Persistent compromise, unauthorized control, data exposure, or loss of software and device integrity across the lifecycle.
15.2.11. Remote Exploitation of Exposed Services¶
A Remote Adversary targets reachable services or protocols to gain unauthorized access, manipulate data, or disrupt availability.
Boundaries Involved: Operational Integration
Potential Impact: Loss of availability, unauthorized command execution, unintended control actions, or compromise of data privacy.
15.2.13. Coordinated Manipulation Across Multiple Devices¶
A Coordinated Distributed Actor attempts to influence many endpoints simultaneously to create aggregate operational impact or to collect or manipulate data at scale.
Boundaries Involved: Operational Integration
Potential Impact: Grid instability, synchronized disruption, large-scale data exposure, or propagation of misleading information into upstream systems.
The following capability expectations describe the security functions that implementations must be able to realize in order to address the risks identified in this threat model.
