T1120 — Peripheral Device Discovery

# T1120 - Peripheral Device Discovery

## SOC Recommendation
Investigate Peripheral Device Discovery activity in the context of Discovery: 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 T1120>"
```

## Escalation Criteria
- Peripheral Device Discovery 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/T1120.json
• /api/recommendations/T1120.json
• /api/d3fend/T1120.json
• /api/mappings/T1120.json
• /api/confluence/T1120.md

Example curl:

curl https://atlas.basyrix.com/api/recommendations/T1120.json

Response:

{
  "technique_id": "T1120",
  "name": "Peripheral Device Discovery",
  "priority": "high",
  "status": "draft",
  "version": "0.1.0",
  "last_reviewed": "2026-07-23",
  "generated_by": "SOC Response Atlas by Basyrix",
  "tactics": [
    "Discovery"
  ],
  "platforms": [
    "Linux",
    "macOS",
    "Windows"
  ],
  "summary": "Adversaries may attempt to gather information about attached peripheral devices and components connected to a computer system. Peripheral devices could include auxiliary resources that support a variety of functionalities such as keyboards, printers, cameras, smart card readers, or removable storage. The information may be used to enhance their awareness of the system and network environment or may be used for further actions.",
  "soc_recommendation": "Investigate Peripheral Device Discovery activity in the context of Discovery: 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 peripheral device discovery 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: \"Peripheral Device Discovery\" -- Identifies use of the Windows file system utility (fsutil.exe) to gather information about attached peripheral devices and components connected to a computer system."
    ]
  },
  "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 T1120",
        "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 T1120>\""
      }
    ],
    "spl": [],
    "esql": [
      {
        "name": "0c7ca5c2-728d-4ad9-b1c5-bbba83ecb1f4 — Peripheral Device Discovery",
        "description": "(EQL) Identifies use of the Windows file system utility (fsutil.exe) to gather information about attached peripheral devices and components connected to a computer system. (Source: Elastic's official detection-rules repository (Elastic License v2).)",
        "query": "process where host.os.type == \"windows\" and event.type == \"start\" and\n  (process.name : \"fsutil.exe\" or ?process.pe.original_file_name == \"fsutil.exe\") and\n  process.args : \"fsinfo\" and process.args : \"drives\""
      },
      {
        "name": "2f2f4939-0b34-40c2-a0a3-844eb7889f43 — PowerShell Suspicious Script with Audio Capture Capabilities",
        "description": "(KUERY) Detects PowerShell script block content that invokes microphone capture routines or WinMM audio APIs. Adversaries may use audio recording to surveil users or capture sensitive conversations for theft or extortion. (Source: Elastic's official detection-rules repository (Elastic License v2).)",
        "query": "event.category:process and host.os.type:windows and\n  powershell.file.script_block_text : (\n    \"Get-MicrophoneAudio\" or\n    (\"Get-AudioDevice\" and \"Recording\" and \"Set-AudioDevice\") or\n    \"WindowsAudioDevice-Powershell-Cmdlet\" or\n    (\n      \"winmm.dll\" and\n      (\n        \"waveInGetNumDevs\" or \"waveInOpen\" or \"waveInStart\" or\n        \"mciSendString\" or \"mciSendStringA\" or \"mciSendStringW\"\n      )\n    )\n  ) and\n  not powershell.file.script_block_text : (\n    \"sentinelbreakpoints\" and \"Set-PSBreakpoint\" and \"PowerSploitIndicators\"\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": [
    "Peripheral Device Discovery 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": "T1120 - Peripheral Device Discovery Response Guidance",
    "labels": [
      "mitre",
      "attack",
      "d3fend",
      "secops",
      "basyrix"
    ],
    "sections": [
      "summary",
      "d3fend_mappings",
      "investigation_steps",
      "response_actions",
      "queries",
      "automation",
      "escalation_criteria",
      "false_positive_considerations"
    ]
  }
}