MITRE ATT&CK T0843.003: Program Append
When to use this skill
Use this skill when the task involves T0843.003, Program Append, ics ATT&CK, TTP mapping, detection engineering, hunting, incident-response enrichment, control validation, or authorized adversary-emulation planning. Treat it as a defensive analysis aid: keep outputs focused on understanding, detecting, mitigating, and safely validating this ATT&CK sub-technique.
Technique context
- ATT&CK domain: ics
- ATT&CK ID: T0843.003
- Technique name: Program Append
- Type: sub-technique
- ATT&CK URL: https://attack.mitre.org/techniques/T0843/003
- Tactics: lateral-movement
- Platforms: Not specified
- Required permissions: Not specified
- Effective permissions: Not specified
- Defenses bypassed: Not specified
ATT&CK description
Adversaries may execute a program append to a PLC to update parts of an existing program. It may or may not require stopping the PLC which may allow it to continue running during transfer and reconfiguration without interruption to process control. Adversaries may leverage this approach to minimize downtime and evade detection.
The ability to perform a program append to the PLC typically relies on access to a workstation with the vendor-specific PLC programming software installed.
Agent workflow
- Clarify scope: identify the system, asset class, log sources, cloud or endpoint platform, and whether the user wants triage, detection, coverage assessment, or safe emulation planning.
- Load bundled resources as needed: use
references/technique-profile.json for structured metadata, references/detection-and-mitigation.md for triage and telemetry guidance, references/known-threat-context.md for ATT&CK relationship context, and templates/ for repeatable outputs.
- Map observations to ATT&CK: compare the user's evidence to the ATT&CK description, tactics, platforms, and known procedure patterns before asserting a match.
- Produce defensive outputs: prioritize hypotheses, telemetry requirements, detection logic ideas, validation steps, containment guidance, and mitigations.
- Preserve uncertainty: distinguish confirmed evidence, plausible indicators, assumptions, and gaps. Recommend what to collect next.
- Stay safe: do not provide malware, credential theft, persistence, evasion, destructive automation, or unauthorized exploitation instructions. For adversary emulation, keep steps bounded to approved lab or control-validation contexts and omit operational abuse details.
Bundled resources
references/technique-profile.json: machine-readable ATT&CK metadata for this technique.references/detection-and-mitigation.md: detection notes, telemetry checklist, triage questions, mitigation candidates, and false-positive considerations.references/known-threat-context.md: ATT&CK relationship context with attribution cautions.templates/detection-brief.md: detection engineering brief template.templates/hunt-plan.md: threat hunt plan template.templates/incident-response-note.md: incident response note template.templates/coverage-assessment.md: ATT&CK coverage assessment template.scripts/render_brief.py: local helper that renders a Markdown defensive brief from technique-profile.json.assets/output-schema.json: JSON schema for structured technique analysis outputs.
To generate a quick brief, run python scripts/render_brief.py --output brief.md from inside this skill directory, or adapt the templates directly.
Detection guidance
No ATT&CK detection guidance was present in the source STIX object.
Useful telemetry and data sources
- Not specified in the STIX object.
Mitigations to consider
- Access Management
- Audit
- Authorization Enforcement
- Code Signing
- Communication Authenticity
- Filter Network Traffic
- Human User Authentication
- Network Allowlists
- Network Segmentation
- Software Process and Device Authentication
Known threat context
Use these examples only as contextual leads, not as proof that an observed event is this technique:
- Triton Safety Instrumented System Attack (campaign)
Recommended output pattern
When responding with this skill, structure the answer as:
- Assessment: whether the evidence supports this ATT&CK mapping and why.
- Evidence: specific indicators, logs, behaviors, and assumptions.
- Detection: telemetry sources, analytic logic, and tuning considerations.
- Response: containment, eradication, recovery, and validation actions.
- Coverage gaps: missing logs, sensors, controls, or environmental details.
- References: include the ATT&CK URL and any user-provided evidence references.
1---2name: attack-ics-t0843-003-program-append3description: Analyze MITRE ATT&CK T0843.003 Program Append in the ics matrix. Use for TTP triage, detection engineering, hunting, defensive emulation planning, mitigations, incident response mapping, ATT&CK coverage, or questions mentioning T0843.003, Program Append, or ics ATT&CK. Adversaries may execute a program append to a PLC to update parts of an existing program.4license: MITRE ATT&CK Terms of Use apply to ATT&CK-derived content. See h5---67# MITRE ATT&CK T0843.003: Program Append89## When to use this skill1011Use this skill when the task involves T0843.003, Program Append, ics ATT&CK, TTP mapping, detection engineering, hunting, incident-response enrichment, control validation, or authorized adversary-emulation planning. Treat it as a defensive analysis aid: keep outputs focused on understanding, detecting, mitigating, and safely validating this ATT&CK sub-technique.1213## Technique context1415- ATT&CK domain: ics16- ATT&CK ID: T0843.00317- Technique name: Program Append18- Type: sub-technique19- ATT&CK URL: https://attack.mitre.org/techniques/T0843/00320- Tactics: lateral-movement21- Platforms: Not specified22- Required permissions: Not specified23- Effective permissions: Not specified24- Defenses bypassed: Not specified2526## ATT&CK description2728Adversaries may execute a program append to a PLC to update parts of an existing program. It may or may not require stopping the PLC which may allow it to continue running during transfer and reconfiguration without interruption to process control. Adversaries may leverage this approach to minimize downtime and evade detection. 2930The ability to perform a program append to the PLC typically relies on access to a workstation with the vendor-specific PLC programming software installed.3132## Agent workflow33341. Clarify scope: identify the system, asset class, log sources, cloud or endpoint platform, and whether the user wants triage, detection, coverage assessment, or safe emulation planning.352. Load bundled resources as needed: use `references/technique-profile.json` for structured metadata, `references/detection-and-mitigation.md` for triage and telemetry guidance, `references/known-threat-context.md` for ATT&CK relationship context, and `templates/` for repeatable outputs.363. Map observations to ATT&CK: compare the user's evidence to the ATT&CK description, tactics, platforms, and known procedure patterns before asserting a match.374. Produce defensive outputs: prioritize hypotheses, telemetry requirements, detection logic ideas, validation steps, containment guidance, and mitigations.385. Preserve uncertainty: distinguish confirmed evidence, plausible indicators, assumptions, and gaps. Recommend what to collect next.396. Stay safe: do not provide malware, credential theft, persistence, evasion, destructive automation, or unauthorized exploitation instructions. For adversary emulation, keep steps bounded to approved lab or control-validation contexts and omit operational abuse details.4041## Bundled resources4243- `references/technique-profile.json`: machine-readable ATT&CK metadata for this technique.44- `references/detection-and-mitigation.md`: detection notes, telemetry checklist, triage questions, mitigation candidates, and false-positive considerations.45- `references/known-threat-context.md`: ATT&CK relationship context with attribution cautions.46- `templates/detection-brief.md`: detection engineering brief template.47- `templates/hunt-plan.md`: threat hunt plan template.48- `templates/incident-response-note.md`: incident response note template.49- `templates/coverage-assessment.md`: ATT&CK coverage assessment template.50- `scripts/render_brief.py`: local helper that renders a Markdown defensive brief from `technique-profile.json`.51- `assets/output-schema.json`: JSON schema for structured technique analysis outputs.5253To generate a quick brief, run `python scripts/render_brief.py --output brief.md` from inside this skill directory, or adapt the templates directly.5455## Detection guidance5657No ATT&CK detection guidance was present in the source STIX object.5859## Useful telemetry and data sources6061- Not specified in the STIX object.6263## Mitigations to consider6465- Access Management66- Audit67- Authorization Enforcement68- Code Signing69- Communication Authenticity70- Filter Network Traffic71- Human User Authentication72- Network Allowlists73- Network Segmentation74- Software Process and Device Authentication7576## Known threat context7778Use these examples only as contextual leads, not as proof that an observed event is this technique:7980- Triton Safety Instrumented System Attack (campaign)8182## Recommended output pattern8384When responding with this skill, structure the answer as:8586- Assessment: whether the evidence supports this ATT&CK mapping and why.87- Evidence: specific indicators, logs, behaviors, and assumptions.88- Detection: telemetry sources, analytic logic, and tuning considerations.89- Response: containment, eradication, recovery, and validation actions.90- Coverage gaps: missing logs, sensors, controls, or environmental details.91- References: include the ATT&CK URL and any user-provided evidence references.
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