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dfir-overview

Use to close the Offensive Vaccine loop on the defender side. The Detector agent produces Sigma / YARA rules from offensive operations; this catalog validates those rules against real memory dumps, event logs, and forensic artifacts using Volatility 3, plaso, and sigma-cli. Without this catalog, detection rules are theoretical.

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SKILL.md
Quality
Evals
Security

Forensicator / DFIR Skill Catalog

Decepticon emits attacks AND detection rules. This catalog feeds the detection rules back through real forensic artifacts to confirm they fire — closing the Offensive Vaccine loop on the operations side.

Playbooks

Inline technique reference — not separately loadable skills. The entries below are summarized here for direct use; there is no separate SKILL.md to open for each. Do NOT call the skill loader on them — apply the technique with your tools using this summary and the Workflow in this file.

TechniqueUse for
volatility-windowsVolatility 3 Windows plugins: pslist, malfind, cmdline, netscan, dlllist, handles
volatility-linuxVolatility 3 Linux: linux.pslist, linux.bash, linux.malfind
plaso-timelinepsort + log2timeline; super-timeline construction; Sigma matchers on the timeline
sigma-cli-validationsigma-cli convert + match against captured event logs
yara-scanyara-x scan against memory dumps and disk images
event-log-miningWindows Event Log (.evtx) extraction + key event ID reference
etw-traceETW provider triage; .etl file extraction
edr-validationReplay an attack against a target with Velociraptor / OSQuery active; capture artifacts

Loop closure workflow

  1. Run an offensive technique (e.g., dcsync from the ad-operator agent).
  2. Detector agent emits Sigma rule describing the expected detection pattern (event 4662 with right ControlAccessRights, etc.).
  3. Defender pushes the Sigma to the customer SIEM via sigma_to_splunk_savedsearch / sigma_to_sentinel_analyticrule / sigma_to_elastic_detection_rule.
  4. Forensicator validates by:
    • Collecting the event log from the DC at attack time.
    • Running sigma-cli convert --target sqlite and matching against the log file.
    • If the match count is 0 → detection rule has a bug. Iterate with Detector.
    • If match count is N → detection works. Record the validation evidence in the engagement knowledge graph.
  5. Patcher proposes the fix; Forensicator validates the patch doesn't break the detection (verify the rule still fires on attempted exploitation of the patched build).

Tools sandbox

  • Volatility 3 (vol, volshell) — already in operator's AGENTS.md tooling.
  • plaso (log2timeline, psort).
  • sigma-cli (sigma convert, sigma check).
  • yara-x (yr) — operator already has it installed at C:\Tools\yara-x\yr.exe.
  • Velociraptor + OSQuery (for live-system validation paths).

Why this is differentiating

Strix doesn't have this. XBOW doesn't have this. The "Offensive Vaccine" promise (every attack becomes a defense improvement) is only deliverable when someone validates the detection. Without Forensicator, the loop stops at "rule written". With it, the loop completes at "rule verified to fire on this attack class against this client's stack".

Repository
PurpleAILAB/Decepticon
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