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T1676 Linked Devices — Attack Simulation

Adversaries may abuse the “linked devices” feature on messaging applications, such as Signal and WhatsApp, to register the user’s account to an adversary-controlled device. By abusing the “linked devices” feature, adversaries may achieve and maintain persistence through the user’s account, may collect information, such as the user’s messages and contacts list, and may send future messages from the linked device. Signal is a messaging application…

Complete technique description

Adversaries may abuse the “linked devices” feature on messaging applications, such as Signal and WhatsApp, to register the user’s account to an adversary-controlled device. By abusing the “linked devices” feature, adversaries may achieve and maintain persistence through the user’s account, may collect information, such as the user’s messages and contacts list, and may send future messages from the linked device.

Signal is a messaging application that uses the open-source Signal Protocol to encrypt messages and calls; similarly, WhatsApp is a messaging application that has end-to-end encryption and other security measures to protect messages and calls. Both applications have a “linked devices” feature that allows users to access their Signal and/or WhatsApp accounts from different devices, such as a Windows or Mac desktop, an iPad or an Android tablet.[WhatsApp_LinkDevice_NoDate][Signal_LinkedDevices_NoDate]

Adversaries may use Phishing techniques to trick the user into scanning a quick-response (QR) code, which is used to link the user’s Signal and/or WhatsApp account to an adversary-controlled device. For example, adversaries may masquerade QR codes as group invites, security alerts or as legitimate instructions for pairing linked devices.
Upon scanning the QR code in Signal, users may click on the “Transfer Message History” option to sync the linked devices, which may allow adversaries to collect more information about the user. Upon scanning the QR code in WhatsApp, the user’s device will automatically send an end-to-end encrypted copy of recent message history to the adversary-controlled device.

Official technique definition · Open in the interactive matrix

Detection telemetry and configuration

These contracts are selected through exact technique-to-data-component relationships or explicitly labelled planning overrides. Configure a collector at the relevant observation point; a telemetry name alone is not coverage.

API Calls · source-mapped

DC0112 collection page — Instrument selected APIs in the owned test app or approved research build; log caller, API, sanitized argument class and return status.

Providers and collection configuration

  • Android logcat: Permitted logs from a consented test device/emulator; output depends on build, permissions and instrumentation.
  • Android dumpsys: Point-in-time service/package state on an authorized development device.
  • Instrumented test application: Own-app permission, API and state callbacks; not universal visibility into other apps.
  • Use a disposable emulator or owned development device with approved debugging. Record OS/API level, app version and instrumentation privileges.
  • Collect only relevant logcat buffers/tags and service snapshots; add explicit own-app instrumentation for events absent from OS logs.
  • Forward sanitized logs and compare before/after state. Remove test data and revoke debugging access after the lab session.

Required normalized fields: package, api, result, thread.

Illustrative collection event

Project-normalized synthetic JSON, not a native provider log, captured event, attack verdict or validated detection. A parser/adapter is required for a real SIEM. Example names, IPs and values are fictional.

{
  "schema": "1200km.telemetry.example.v1",
  "synthetic": true,
  "timestamp": "2026-09-27T12:00:00Z",
  "telemetry_id": "DC0112",
  "collector": "illustrative-lab-collector",
  "observation": {
    "package": "test.example.lab",
    "api": "android.hardware.camera2.CameraManager.openCamera",
    "result": "permission_denied",
    "thread": "main"
  }
}

Visibility limits: Android tooling does not imply iOS coverage. Standard mobile apps cannot observe all other apps or protected OS internals; MDM status is not full API, filesystem or content telemetry.

Network Connection Creation · source-mapped

DC0082 collection page — Enable scoped Sysmon NetworkConnect (3), disabled by default, or a platform-equivalent process-aware network sensor.

Providers and collection configuration

  • Microsoft Sysmon: Windows event-based collection; enable the event types needed below.
  • Linux Audit: Linux alternative for supported system-call and file events; different semantics and fields.
  • Apple Endpoint Security clients: macOS alternative where the subscribed event exists; requires an entitled, approved client, not an iOS collector.
  • On a disposable Windows host, review the installed Sysmon schema and current configuration; merge scoped event filters into the existing policy rather than replacing it.
  • Forward Microsoft-Windows-Sysmon/Operational to the lab collector. Preserve event ID, timestamp, computer, process identifiers and the original event.
  • For Linux or macOS, select the equivalent sensor separately and test its emitted fields; a Windows event ID does not transfer across platforms.

Required normalized fields: process_guid, destination_ip, destination_port, protocol, initiated.

Illustrative collection event

Project-normalized synthetic JSON, not a native provider log, captured event, attack verdict or validated detection. A parser/adapter is required for a real SIEM. Example names, IPs and values are fictional.

{
  "schema": "1200km.telemetry.example.v1",
  "synthetic": true,
  "timestamp": "2026-09-27T12:00:00Z",
  "telemetry_id": "DC0082",
  "collector": "illustrative-lab-collector",
  "observation": {
    "process_guid": "lab-process-001",
    "destination_ip": "198.51.100.20",
    "destination_port": 443,
    "protocol": "tcp",
    "initiated": true
  }
}

Visibility limits: Event filtering and sensor versions change coverage. High-volume image-load and process-access collection needs tuning; endpoint events alone do not establish intent.

Network Traffic Content · source-mapped

DC0085 collection page — Scope approved packet capture/protocol content collection to the lab flow; retain capture provenance and truncation indicators.

Providers and collection configuration

  • Zeek: Connection and protocol metadata from traffic visible to the sensor.
  • Suricata EVE: Configured flow, alert, DNS, HTTP, TLS and protocol records.
  • Use an authorized lab TAP/SPAN, virtual mirror or gateway interface. Define which traffic crosses it; avoid assuming visibility into every segment.
  • Enable the required Zeek analyzers or Suricata EVE event types. Export logs with sensor identity, clock synchronization and flow correlation identifiers.
  • Monitor capture loss, truncation and exporter sampling. Capture payload only with approval and restrictive retention; encryption normally prevents plaintext inspection.

Required normalized fields: flow_id, protocol, method, path, payload_excerpt.

Illustrative collection event

Project-normalized synthetic JSON, not a native provider log, captured event, attack verdict or validated detection. A parser/adapter is required for a real SIEM. Example names, IPs and values are fictional.

{
  "schema": "1200km.telemetry.example.v1",
  "synthetic": true,
  "timestamp": "2026-09-27T12:00:00Z",
  "telemetry_id": "DC0085",
  "collector": "illustrative-lab-collector",
  "observation": {
    "flow_id": "lab-flow-1",
    "protocol": "http",
    "method": "GET",
    "path": "/lab-check",
    "payload_excerpt": "LAB_TELEMETRY_CHECK"
  }
}

Visibility limits: Flows are not packet payloads. NAT, asymmetric routes, encryption, missing mirrors and sampling can hide attribution or content. A destination connection alone does not prove malicious intent.

Permissions Request · source-mapped

DC0116 collection page — Correlate own-app request/callback instrumentation with the consented test-device prompt. A request callback alone does not prove a prompt appeared (for example, a previously denied permission).

Providers and collection configuration

  • Android logcat: Permitted logs from a consented test device/emulator; output depends on build, permissions and instrumentation.
  • Android dumpsys: Point-in-time service/package state on an authorized development device.
  • Instrumented test application: Own-app permission, API and state callbacks; not universal visibility into other apps.
  • Use a disposable emulator or owned development device with approved debugging. Record OS/API level, app version and instrumentation privileges.
  • Collect only relevant logcat buffers/tags and service snapshots; add explicit own-app instrumentation for events absent from OS logs.
  • Forward sanitized logs and compare before/after state. Remove test data and revoke debugging access after the lab session.

Required normalized fields: package, permission, action, prompt_observed, result.

Illustrative collection event

Project-normalized synthetic JSON, not a native provider log, captured event, attack verdict or validated detection. A parser/adapter is required for a real SIEM. Example names, IPs and values are fictional.

{
  "schema": "1200km.telemetry.example.v1",
  "synthetic": true,
  "timestamp": "2026-09-27T12:00:00Z",
  "telemetry_id": "DC0116",
  "collector": "illustrative-lab-collector",
  "observation": {
    "package": "test.example.lab",
    "permission": "android.permission.CAMERA",
    "action": "permission_prompt",
    "prompt_observed": true,
    "result": "denied"
  }
}

Visibility limits: Android tooling does not imply iOS coverage. Standard mobile apps cannot observe all other apps or protected OS internals; MDM status is not full API, filesystem or content telemetry.

Detection rules and analytic guidance

Open the dedicated detection workspace · Existing query engineering

DET0716 Detection of Linked Devices

MITRE detection strategy

AN1845 Analytic 1845

For Android, detect Linked Devices by correlating analyst-visible device/network evidence and management state; use streaming or batched telemetry only where the documented collector is deployed. Correlate API Calls via Application Vetting / Instrumented Dynamic Analysis [Dynamic API/runtime trace: camera activated within app IN $MessagingAppList$ — QR scan requires camera access; activation in messaging app context is the trigger signal]; Network Connection Creation via Android Enterprise Network Logging / Enterprise VPN [DevicePolicyManager.retrieveNetworkLogs(): DnsEvent / ConnectEvent; VPN flow metadata]; Network Traffic Content via Enterprise Secure Web Gateway / Proxy [DNS/HTTP(S) inspection or proxy transaction metadata where enterprise decryption/inspection is deployed]. Alert on a sequence or state change inconsistent with the device/app baseline, approved management policy, or expected user workflow; do not infer unobserved API calls, file/process activity, or payload content from management state alone.

Platforms: Android.

  • API Calls — mobile:DynamicAnalysis; channel Dynamic API/runtime trace: camera activated within app IN $MessagingAppList$ — QR scan requires camera access; activation in messaging app context is the trigger signal.
  • Network Connection Creation — android:EnterpriseNetworkLog; channel DevicePolicyManager.retrieveNetworkLogs(): DnsEvent / ConnectEvent; VPN flow metadata.
  • Network Traffic Content — webproxy:applog; channel DNS/HTTP(S) inspection or proxy transaction metadata where enterprise decryption/inspection is deployed.

AN1846 Analytic 1846

For iOS, detect Linked Devices by correlating analyst-visible device/network evidence and management state; use streaming or batched telemetry only where the documented collector is deployed. Correlate Network Connection Creation via Apple Network Extension / Enterprise VPN [NEFilterFlow / per-app VPN / secure-web-gateway flow metadata]; Network Traffic Content via Enterprise Secure Web Gateway / Proxy [DNS/HTTP(S) inspection or proxy transaction metadata where enterprise decryption/inspection is deployed]; Permissions Request via Application Vetting [Code-signing entitlements and Info.plist privacy usage-description keys]. Alert on a sequence or state change inconsistent with the device/app baseline, approved management policy, or expected user workflow; do not infer unobserved API calls, file/process activity, or payload content from management state alone.

Platforms: iOS.

  • Network Connection Creation — iOS:NetworkExtension; channel NEFilterFlow / per-app VPN / secure-web-gateway flow metadata.
  • Network Traffic Content — webproxy:applog; channel DNS/HTTP(S) inspection or proxy transaction metadata where enterprise decryption/inspection is deployed.
  • Permissions Request — mobile:ApplicationVetting; channel Code-signing entitlements and Info.plist privacy usage-description keys.
Source rule directory and observation requirements

No exact-tagged Sigma source rule was imported. This does not establish that the technique is undetectable; the MITRE guidance and collection requirements remain relevant.

Before treating a rule as coverage

  1. Read the actual condition and logsource; identify attacker-side, victim-side or third-party visibility.
  2. Map native sensor fields, parse times and identities, then compile for the selected backend.
  3. Replay a behavior-positive case, a normal control, an authorized look-alike and a missing-telemetry case.
  4. Record matches and misses with rule version and source events. No match is inconclusive when required telemetry is absent.

Anomaly-based detection

No exact technique-specific Atlas model is present for T1676 in the selected source snapshot. The following is a design worksheet, not a newly validated model.

Anomaly engineering worksheet

Start from the exact analytic above. The collection-specific lenses below are analyst recommendations; they do not assert that an arbitrary statistical deviation detects this technique.

  • Mobile lab instrumentation: Per owned device, app version and permission state: unexpected API/permission changes, background activity and network destinations. OS privacy restrictions and emulator differences limit observability.
  • Endpoint activity: Per host role and user: rare process/object combinations, bursts of object access or modification, and ordered parent/action sequences. Compare maintenance windows and signed software rollout activity.
  • Network and protocol telemetry: Per source and observation point: connection rate, destination-host/port fan-out, response/failure ratio and previously unseen destinations. Compare equivalent time windows; separate authorized scanners, NAT and sampling effects.
  1. Define an entity/peer group and feature; exclude the evaluation period from baseline training.
  2. Use representative normal and maintenance activity. Do not invent a production threshold from a synthetic example.
  3. Evaluate held-out behavior-positive and benign cases; measure false positives, misses and telemetry loss separately.
  4. Keep abnormality separate from maliciousness. Correlate with the behavior-specific source evidence.

Anomaly Detection Atlas · Baseline, validation and blind spots

Attack tools and documented software

No reviewed lab-tool association is selected for this exact technique. This is a curation gap, not a statement that no tool can implement the behavior.

Simulation design and documented procedures

Atomic evidence: no compatible candidate in this snapshot. Live lab status: not run for these imported procedures.

Use owned test devices or emulators, disposable app accounts and test data. Verify platform/version instrumentation; desktop test procedures do not establish mobile coverage.

No compatible Atomic procedure is present in this pinned evidence set. Technical feasibility has not been ruled out. A custom procedure must define the behavior, target, collection point, success observable and rollback before execution.

Technique-specific experiment contract

  1. Choose one procedure implementing T1676 Linked Devices; identify the observable behavior in the source definition, not just its tactic.
  2. Record exact target, tool/version, inputs, privileges, network limits and approval. Never run an imported default target automatically.
  3. Enable the collection sources above and verify a benign baseline reaches the detector.
  4. Run only the approved isolated scenario; capture native events and an independent behavior observable.
  5. Evaluate the exact rule/model, restore the lab, and preserve configuration, event hashes, alerts, controls and misses.

Synthetic logs and offline contract check

Download synthetic collection fixture (JSON) · Download the complete engineering workbook

This fixture exercises the listed collection fields. It does not reproduce Linked Devices, label its example events as malicious, or measure detection effectiveness. Use the exact analytic and selected procedure to build an independently labelled behavior-positive dataset.

Not run in this browser. No network scan or attack command is executed by this control.

Validation status and remaining work

Source identity
Joined by exact technique/object IDs against hash-pinned sources.
Collection fixture
Available for offline schema exercises; not attack emulation.
Native telemetry / backend / real attack
Not validated for these imported procedures. Source fidelity and page tests cannot establish sensor or detector effectiveness.

All-page audit and evidence inventory · This page’s machine-readable workbook

Sources and evidence boundaries

Pinned MITRE STIX source · SHA-256 824f7d8a37e7893b29e4c6ca6d87b5fbbf3b228ec6384f1a69ee20d523ff59e5. Definition and procedure context are reproduced from this snapshot, not independently re-investigated incidents.

Source-linked mitigations
  • M1011 User Guidance

    For Android devices, users should be advised to enable Google Play Protect, which checks the device itself and the applications for malicious behavior. For iOS devices, users who are concerned about being targeted should consider enabling Lockdown Mode, which provides extreme protection of the device as well as data stored and transmitted.
    In general, users should be advised against scanning QR codes and/or clicking on suspicious links or text messages, which may masquerade as device-linking instructions by Signal or WhatsApp.

Connected ecosystem references

Linked tags

Detection and collection

T1676 detection workspace

No reviewed association in this snapshot.

Pinned research references. No browser attack runner or production-validated detector is asserted. Imported procedures remain unvalidated; any bounded lab evidence has its own scope. ATT&CK / Atomic provenance · Detection provenance.