T1601 — Modify System Image

# T1601 - Modify System Image

## SOC Recommendation
Investigate Modify System Image activity in the context of Defense Impairment: confirm scope, affected host/identity, and whether it matches expected administrative behaviour before deciding this is benign.

## D3FEND Mappings
| D3FEND Technique | Relationship | Practical SOC Action |
|---|---|---|
| Network Traffic Analysis | Detect | Monitor for Network Traffic Analysis indicators relevant to this technique. |

## Investigation Steps
1. Review Defender for Endpoint / Defender XDR alerts and timeline for the affected host or identity.
2. Check Sentinel analytics rules and incidents correlated with this technique.
3. Review Entra ID sign-in and audit logs if the technique involves an identity or cloud resource.

## Evidence to Collect
- Host or resource affected
- Account or identity involved
- Timestamp of the activity
- Related process, file, or network artifact
- Any preceding or follow-on alerts

## Response Actions
| Action | Risk | Automation Safe | Approval Required |
|---|---|---|---|
| Contain the affected host or account | Medium | No | Yes |
| Collect and preserve evidence | Low | Yes | No |

## KQL
```kql
DeviceEvents
| where TimeGenerated > ago(24h)
| where ActionType has "<tune to T1601>"
```

## Escalation Criteria
- Modify System Image activity observed on a privileged account or critical system.
- Activity follows or precedes other suspicious behaviour in the same investigation.
- Automated triage cannot confidently rule out malicious intent.

## False Positive Considerations
- Legitimate administrative or maintenance activity matching this pattern.
- Approved security testing or red team exercise.
- Known benign software producing similar telemetry.

Generated by SOC Response Atlas by Basyrix.

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• /api/techniques/T1601.json
• /api/recommendations/T1601.json
• /api/d3fend/T1601.json
• /api/mappings/T1601.json
• /api/confluence/T1601.md

Example curl:

curl https://atlas.basyrix.com/api/recommendations/T1601.json

Response:

{
  "technique_id": "T1601",
  "name": "Modify System Image",
  "priority": "medium",
  "status": "draft",
  "version": "0.1.0",
  "last_reviewed": "2026-07-23",
  "generated_by": "SOC Response Atlas by Basyrix",
  "tactics": [
    "Defense Impairment"
  ],
  "platforms": [
    "Network Devices"
  ],
  "summary": "Adversaries may make changes to the operating system of embedded network devices to weaken defenses and provide new capabilities for themselves. On such devices, the operating systems are typically monolithic and most of the device functionality and capabilities are contained within a single file. To change the operating system, the adversary typically only needs to affect this one file, replacing or modifying it...",
  "soc_recommendation": "Investigate Modify System Image activity in the context of Defense Impairment: confirm scope, affected host/identity, and whether it matches expected administrative behaviour before deciding this is benign.",
  "d3fend_mappings": [
    {
      "id": "D3-NTA",
      "name": "Network Traffic Analysis",
      "relationship": "detect",
      "practical_action": "Monitor for Network Traffic Analysis indicators relevant to this technique.",
      "tooling": [
        "Sentinel",
        "Defender for Endpoint"
      ]
    }
  ],
  "investigation_steps": {
    "microsoft": [
      "Review Defender for Endpoint / Defender XDR alerts and timeline for the affected host or identity.",
      "Check Sentinel analytics rules and incidents correlated with this technique.",
      "Review Entra ID sign-in and audit logs if the technique involves an identity or cloud resource."
    ],
    "generic": [
      "Confirm whether the observed modify system image activity matches expected administrative or application behaviour.",
      "Identify the host, account, or resource where the activity occurred and its business criticality.",
      "Check for related alerts before and after this activity to reconstruct the broader intrusion timeline.",
      "Real detection reference: \"Kernel Load or Unload via Kexec Detected\" -- This detection rule identifies the usage of kexec, helping to uncover unauthorized kernel replacements and potential compromise of the system's integrity. Kexec is a Linux feature that enables the loading and execution of a different kernel without going through the typical boot process..."
    ]
  },
  "evidence_to_collect": [
    "Host or resource affected",
    "Account or identity involved",
    "Timestamp of the activity",
    "Related process, file, or network artifact",
    "Any preceding or follow-on alerts"
  ],
  "response_actions": [
    {
      "name": "Contain the affected host or account",
      "category": "Containment",
      "risk": "Medium",
      "automation_safe": false,
      "approval_required": true,
      "tool": "Defender for Endpoint / Entra ID",
      "notes": "Requires approval -- confirm malicious intent before isolating a host or disabling an account."
    },
    {
      "name": "Collect and preserve evidence",
      "category": "Investigation",
      "risk": "Low",
      "automation_safe": true,
      "approval_required": false,
      "tool": "Defender for Endpoint",
      "notes": "Safe -- read-only evidence collection."
    }
  ],
  "queries": {
    "kql": [
      {
        "name": "Starting point for T1601",
        "description": "Generic starting query -- tune to the specific data source relevant to this technique.",
        "query": "DeviceEvents\n| where TimeGenerated > ago(24h)\n| where ActionType has \"<tune to T1601>\""
      }
    ],
    "spl": [],
    "esql": [
      {
        "name": "4d4c35f4-414e-4d0c-bb7e-6db7c80a6957 — Kernel Load or Unload via Kexec Detected",
        "description": "(EQL) This detection rule identifies the usage of kexec, helping to uncover unauthorized kernel replacements and potential compromise of the system's integrity. Kexec is a Linux feature that enables the loading and execution of a different kernel without going through the typical boot process... (Source: Elastic's official detection-rules repository (Elastic License v2).)",
        "query": "process where host.os.type == \"linux\" and event.type == \"start\" and\nevent.action in (\"exec\", \"exec_event\", \"start\", \"ProcessRollup2\", \"executed\", \"process_started\") and\nprocess.name == \"kexec\" and process.args in (\"--exec\", \"-e\", \"--load\", \"-l\", \"--unload\", \"-u\") and\nnot (\n  process.parent.name in (\"kdumpctl\", \"unload.sh\") or\n  process.parent.args in (\"/usr/bin/kdumpctl\", \"/usr/sbin/kdump-config\", \"/usr/lib/kdump/unload.sh\")\n)"
      }
    ]
  },
  "automation": {
    "safe": [
      "Add recommendation as Sentinel incident comment.",
      "Run enrichment queries.",
      "Create ServiceNow SecOps task."
    ],
    "approval_required": [
      "Contain or disable the affected host/account.",
      "Any change to production configuration."
    ]
  },
  "escalation_criteria": [
    "Modify System Image activity observed on a privileged account or critical system.",
    "Activity follows or precedes other suspicious behaviour in the same investigation.",
    "Automated triage cannot confidently rule out malicious intent."
  ],
  "false_positive_considerations": [
    "Legitimate administrative or maintenance activity matching this pattern.",
    "Approved security testing or red team exercise.",
    "Known benign software producing similar telemetry."
  ],
  "confluence": {
    "title": "T1601 - Modify System Image Response Guidance",
    "labels": [
      "mitre",
      "attack",
      "d3fend",
      "secops",
      "basyrix"
    ],
    "sections": [
      "summary",
      "d3fend_mappings",
      "investigation_steps",
      "response_actions",
      "queries",
      "automation",
      "escalation_criteria",
      "false_positive_considerations"
    ]
  }
}