hunting-for-anomalous-powershell-execution

hunting-for-anomalous-powershell-execution is a skill for Claude Code, Codex from adriannoes/awesome-agentic-ai. It costs 102 tokens per session (620 once invoked), scanned A, original, MIT.

A guide to investigating suspicious PowerShell activity through Windows event logs. PowerShell is Microsoft's command-line and scripting tool; the guide focuses on logs that record scripts, modules, process creation, and signs of obfuscation or credential theft.

In plain words
What is it for?
Use it to parse EVTX files, reconstruct multi-part scripts, search for encoded commands and bypass attempts, and create detection queries for PowerShell attacks.
Why use it?
It helps analysts uncover malicious scripts, including commands designed to hide their purpose or run without creating ordinary files. Combining several event sources gives more context than examining one log alone.

Skill for Claude CodeCodex

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

Good fit Use it to parse EVTX files, reconstruct multi-part scripts, search for encoded commands and bypass attempts, and create detection queries for PowerShell attacks.

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Install with agentmods
npx agentmods add skills/adriannoes/awesome-agentic-ai/hunting-for-anomalous-powershell-execution
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 adriannoes/awesome-agentic-ai --skill hunting-for-anomalous-powershell-execution
Clone the repo
git clone --depth 1 https://github.com/adriannoes/awesome-agentic-ai

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-for-anomalous-powershell-execution

README.md
[![agentmods](https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/hunting-for-anomalous-powershell-execution/github.svg)](https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/hunting-for-anomalous-powershell-execution)
Your own site
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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.

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Your own site · 80×15
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/hunting-for-anomalous-powershell-execution"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/hunting-for-anomalous-powershell-execution.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 102 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 620 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00102 $0.00620
Opus 5 $0.00051 $0.00310
Sonnet 5 $0.00020 $0.00124
Haiku 4.5 $0.00010 $0.00062

Measured 8d ago against content hash 7f02bb8bac8b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

hunting-for-anomalous-powershell-execution 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/agent.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.

cursor-claude-codex/skills/anthropic-cybersecurity-skills/skills/hunting-for-anomalous-powershell-execution/SKILL.md · 82 lines

What it actually says

Hunting for Anomalous PowerShell Execution

Overview

PowerShell Script Block Logging (Event ID 4104) records the full deobfuscated script text executed on a Windows endpoint, making it the primary data source for hunting malicious PowerShell. Combined with Module Logging (4103) and process creation events, analysts can detect encoded commands, AMSI bypass patterns, download cradles, credential theft tools, and fileless attack techniques even when the attacker uses obfuscation layers.

When to Use

  • When investigating security incidents that require hunting for anomalous powershell execution
  • When building detection rules or threat hunting queries for this domain
  • When SOC analysts need structured procedures for this analysis type
  • When validating security monitoring coverage for related attack techniques

Prerequisites

  • Windows Event Log exports (.evtx) from Microsoft-Windows-PowerShell/Operational
  • Python 3.8+ with python-evtx and lxml libraries
  • Script Block Logging enabled via Group Policy
  • Understanding of common PowerShell attack techniques

Steps

  1. Parse EVTX files extracting Event 4104 script block text and metadata
  2. Reassemble multi-part script blocks using ScriptBlock ID correlation
  3. Scan script text for AMSI bypass indicators and obfuscation patterns
  4. Detect encoded command execution and base64 payloads
  5. Identify download cradles, credential dumping, and lateral movement commands
  6. Score and prioritize findings by threat severity

Expected Output

{
  "total_events": 1247,
  "suspicious_events": 23,
  "amsi_bypass_attempts": 2,
  "encoded_commands": 8,
  "download_cradles": 5,
  "credential_access": 3
}
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 · 82 lines · 102 tokens per session scan A 7f02bb8bac8b

Subscribe to this mod's changes

hunting-for-anomalous-powershell-execution is a skill published in the GitHub repository adriannoes/awesome-agentic-ai (57 stars, last pushed 14d ago), licensed MIT. It adds 102 tokens to every session and 620 once invoked, about $0.0005 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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