hunting-ransomware-precursor-behavior

hunting-ransomware-precursor-behavior is a skill for Claude Code, Codex from meltedinhex/analyst-ai-pack. It costs 76 tokens per session (749 once invoked), scanned A, original, Apache-2.0.

A security-hunting guide for finding ransomware preparation steps before files are encrypted, such as deleting backups, disabling recovery, stopping security tools, and changing many files at once.

In plain words
What is it for?
Use it to analyze process and command-line telemetry, identify recovery and backup tampering, and prioritize hosts showing several warning signs together.
Why use it?
It helps defenders spot an attack early, when they may still be able to intervene. It separates preparation activity from the later encryption itself.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to analyze process and command-line telemetry, identify recovery and backup tampering, and prioritize hosts showing several warning signs together.

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Install with agentmods
npx agentmods add skills/meltedinhex/analyst-ai-pack/hunting-ransomware-precursor-behavior
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add meltedinhex/analyst-ai-pack --skill hunting-ransomware-precursor-behavior
Clone the repo
git clone --depth 1 https://github.com/meltedinhex/analyst-ai-pack

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for hunting-ransomware-precursor-behavior

README.md
[![agentmods](https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/hunting-ransomware-precursor-behavior/github.svg)](https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/hunting-ransomware-precursor-behavior)
Your own site
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/hunting-ransomware-precursor-behavior"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/hunting-ransomware-precursor-behavior/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for hunting-ransomware-precursor-behavior

Your own site · 80×15
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/hunting-ransomware-precursor-behavior"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/hunting-ransomware-precursor-behavior.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 76 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 749 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00076 $0.00749
Opus 5 $0.00038 $0.00375
Sonnet 5 $0.00015 $0.00150
Haiku 4.5 $0.00008 $0.00075

Measured 8d ago against content hash b221dcf86f05, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

hunting-ransomware-precursor-behavior scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/analyst.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/hunting-ransomware-precursor-behavior/SKILL.md · 90 lines

How it starts

The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Hunting Ransomware Precursor Behavior

When to Use

  • You have endpoint process/command telemetry and want to catch the steps ransomware takes before encrypting — deleting shadow copies, disabling recovery, killing security tools, and stopping backup/database services.
  • You want early warning to intervene before payload detonation.

Do not use this as a substitute for blocking the encryption itself — it is an early-warning hunt for the preparation phase, not a recovery procedure.

Prerequisites

  • Process-creation telemetry (with command line) and optionally service/file telemetry.

Workflow

Step 1: Hunt recovery-inhibition commands

python scripts/analyst.py hunt events.csv

Flags vssadmin delete shadows, wmic shadowcopy delete, wbadmin delete catalog, bcdedit /set recoveryenabled no / bootstatuspolicy ignoreallfailures, and wevtutil cl.

Step 2: Detect defense and service tampering

Surface stopping/killing of AV/EDR and backup/DB services (net stop, taskkill, sc stop) targeting veeam, sql, backup, sophos, defender, etc.

Step 3: Correlate and prioritize

A host showing recovery-inhibition + service-stop in a short window is a high-priority pre-encryption signal — escalate immediately.

Step 4: Operationalize

Write a high-severity detection for shadow-copy deletion and recovery disabling.

Validation

  • Recovery-inhibition commands are detected with their specific syntax.
  • Security/backup service tampering is identified by target service names.
  • Findings map to ATT&CK T1490 / T1489 (and precede T1486).

Pitfalls

  • Admins occasionally delete shadow copies legitimately — corroborate with co-occurring tampering.
  • LOLBin variants (wmic, PowerShell Get-WmiObject Win32_ShadowCopy | Remove) evading vssadmin-only rules.
  • Fast attacks where precursor and encryption are near-simultaneous — alert must be real-time.

References

Read the full file on GitHub · 90 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 90 lines · 76 tokens per session scan A b221dcf86f05

Subscribe to this mod's changes

hunting-ransomware-precursor-behavior is a skill published in the GitHub repository meltedinhex/analyst-ai-pack (22 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 76 tokens to every session and 749 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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