# Incident: Analyst-selected activity for investigation

**Case:** CASE-SEED  
**Generated:** 2026-09-26 11:12:31 UTC  
**Status:** complete  
**Severity:** MEDIUM  |  **Grouping confidence:** low  
**Hosts:** CLIENT1  
**Accounts:** client1  
**Window:** 2024-12-28 15:02:06 -> 15:02:06 UTC (0s)

> This report was produced by an automated investigation over telemetry from: **winlogbeat**. It presents evidence-backed findings for analyst review and does not authorise or perform any response action.

## Verdict

**Disposition:** Abstain  
**Engine:** deterministic  |  **Profile:** operational-v6  |  **Model:** none (deterministic engine)  
**Decided by:** deterministic triage of the seed findings  
**Evidence basis:** 5 typed observation(s) checked against recorded telemetry; 0 claim(s) rejected by verification; 1 specialist step(s) run (endpoint); 2 tool call(s) served, 0 refused.  
**Supporting event ids:** none cited by the concluding explanations.

*This system does not compute a confidence score for its verdict. The evidence basis is a count of what was checked, not a measure of how likely the verdict is.*

## Investigation Tree

```text
Initial alert: Analyst-selected activity for investigation
  rules ANALYST-SEED; 1 seed event(s): wlb-process-0001058
  ↓
ATH investigation (engine deterministic)
  ├── endpoint
  │     why: only eligible specialist; case evidence rests on process_command_line, process_execution, process_lineage telemetry (from ANALYST-SEED)
  │     tools: get_events, process_tree
  │     new events: 2 retrieved; shown: wlb-process-0001057, wlb-process-0001055
  └── evidence_verifier
        why: validate typed observations against cited telemetry
  stopped: no specialist has further useful work on the available evidence
  ↓
Verdict: Abstain
```

## Reasoning Summary

No model-written reasoning: this run used no model. Its reasoning is the specialist trace in the investigation tree and the findings below.

## Executive Summary

This report covers CASE-SEED, correlating 1 detection finding(s) across 1 host(s) (CLIENT1) and 1 account(s) (client1) between 15:02:06 and 15:02:06 UTC on 2024-12-28. 5 statement(s) below are directly established by telemetry, 2 are evidence-supported inferences, and 0 are explicitly unverified hypotheses requiring analyst confirmation. This report does not authorise or perform any response action. All recommendations below require human review before action is taken.

## Attack Timeline

| Time | Rule | Severity | User | Host / Movement | ATT&CK | Events |
| --- | --- | --- | --- | --- | --- | --- |
| 15:02:06 | ANALYST-SEED | MEDIUM | client1 | CLIENT1 | - | wlb-process-0001058 |

## Findings

### Confirmed (FACT) (5)

*Typed observations checked against recorded telemetry.*

- Confirmed: Event wlb-process-0001055 records process identity sysmon:416dd0c5-12ed-6770-2604-000000000c00.
  - Evidence: `wlb-process-0001055`
- Confirmed: Event wlb-process-0001057 records process identity sysmon:416dd0c5-12ee-6770-2804-000000000c00.
  - Evidence: `wlb-process-0001057`
- Confirmed: Event wlb-process-0001058 records process identity sysmon:416dd0c5-12ee-6770-2904-000000000c00.
  - Evidence: `wlb-process-0001058`
- Confirmed: Process event wlb-process-0001057 identifies the instance in wlb-process-0001055 as its parent.
  - Evidence: `wlb-process-0001055, wlb-process-0001057`
- Confirmed: Process event wlb-process-0001058 identifies the instance in wlb-process-0001057 as its parent.
  - Evidence: `wlb-process-0001057, wlb-process-0001058`

### Assessed (INFERENCE) (2)

*Interpretations and summaries; citation or predicate checks do not verify their free-text meaning.*

- Assessed: Unverified summary: On CLIENT1, firefox.exe (PID 9284) was started by firefox.exe under account client1.
  - Evidence: `wlb-process-0001058`
- Assessed: Unverified summary: Execution chain on CLIENT1: - -> cmd.exe -> firefox.exe -> firefox.exe.
  - Evidence: `wlb-process-0001058, wlb-process-0001057, wlb-process-0001055`

### Unconfirmed Hypotheses (0)

*Possible explanations that have NOT been verified. Treat as open questions for the analyst, not as findings.*

_None._

## Evidence Checks

5 typed observations verified; 2 unstructured summaries retained as interpretations.

Predicate support does not establish malicious intent or verify the accompanying prose.

## Recommended Next Steps

*These are investigative recommendations for a human analyst. No response action has been taken or is authorised by this report.*

1. **Retrieve email gateway or web-proxy logs to establish the initial access vector.**
   - Rationale: No detection in this case targets initial access, so the delivery mechanism (e.g. a phishing attachment) is inferred from process lineage rather than confirmed from delivery telemetry.
   - Based on: MITRE ATT&CK tactic coverage gap: Initial Access
2. **Escalate to a human analyst for validation before any remediation action is taken.**
   - Rationale: This system performs read-only investigation only. It has no capability to disable accounts, isolate hosts, or otherwise remediate, and this report is not authorisation to do so.
   - Based on: system design constraint

## Limitations & Scope

- Telemetry underlying this report came from: winlogbeat. Field coverage depends entirely on what the originating export or sensor captured; this project's canonical schema does not model every field a real EDR product exposes (e.g. file hashes, signer information, session identifiers), and any of those were dropped during normalization.
- ATT&CK mappings are interpretations of observed behaviour against a public taxonomy. They indicate that behaviour is consistent with a technique, not that an adversary performed it.
- Grouping confidence describes how strongly correlated findings are linked to each other, not whether an intrusion occurred.
- No evidence was found for the following ATT&CK tactics: Initial Access, Discovery, Credential Access, Lateral Movement, Collection, Exfiltration. Their absence may reflect that the activity did not occur, or that available telemetry cannot observe it.
- Typed predicates are checked against recorded telemetry; free-text interpretations are not semantically verified. Missing identity is not a confirmed process link, and recorded event order does not establish causation.

## Investigation Trace

Agents run: endpoint  
Tool calls made: 2

- step 1: endpoint -- only eligible specialist; case evidence rests on process_command_line, process_execution, process_lineage telemetry (from ANALYST-SEED)
- step 2: stop -- no specialist has further useful work on the available evidence
- evidence verification: 5 checked observations; 2 summaries reclassified

## Evidence Appendix

All 3 telemetry events underlying this report, chronologically. Every claim above cites specific event ids from this list.

| Event ID | Time | Device | User | Summary |
| --- | --- | --- | --- | --- |
| `wlb-process-0001055` | 15:02:05 | CLIENT1 | client1 | - -> cmd.exe \| C:\Windows\system32\cmd.exe /c ""C:\\Program Files (x86)\\Mozilla Firefox\\firefox.exe" C:\Users\client1\Documents\attachments\trial.pdf" |
| `wlb-process-0001057` | 15:02:06 | CLIENT1 | client1 | cmd.exe -> firefox.exe \| "C:\\Program Files (x86)\\Mozilla Firefox\\firefox.exe"  C:\Users\client1\Documents\attachments\trial.pdf |
| `wlb-process-0001058` | 15:02:06 | CLIENT1 | client1 | firefox.exe -> firefox.exe \| "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" C:\Users\client1\Documents\attachments\trial.pdf |