How do I install the Analyzing Powershell Script Block Logging skill?

Run npx skillmds@latest add micsapp/analyzing-powershell-script-block-logging in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Analyzing Powershell Script Block Logging safe to use?

This skill has not completed SkillMD's automated safety review yet. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. Capability flags: executes scripts. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Analyzing Powershell Script Block Logging?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Analyzing Powershell Script Block Logging free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under Apache-2.

Who published Analyzing Powershell Script Block Logging?

micsapp (@micsapp) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Analyzing Powershell Script Block Logging by micsapp

Name: Analyzing Powershell Script Block Logging
Rating: 4.2 (5 reviews)
Author: micsapp

Analyzing Powershell Script Block Logging

Parse Windows PowerShell Script Block Logs (Event ID 4104) from EVTX files to detect obfuscated commands, encoded payloads, and living-off-the-land techniques. Uses python-evtx to extract and reconstruct multi-block scripts, applies entropy analysis and pattern matching for Base64-encoded commands, Invoke-Expression abuse, download cradles, and AMSI bypass attempts.

micsapp Updated Sep 8, 2026 3 repo stars

File contents

Analyzing PowerShell Script Block Logging

When to Use

When investigating security incidents that require analyzing powershell script block logging
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

Familiarity with security operations concepts and tools
Access to a test or lab environment for safe execution
Python 3.8+ with required dependencies installed
Appropriate authorization for any testing activities

Instructions

Install dependencies: pip install python-evtx lxml
Collect PowerShell Operational logs: Microsoft-Windows-PowerShell%4Operational.evtx
Parse Event ID 4104 entries using python-evtx to extract ScriptBlockText, ScriptBlockId, and MessageNumber/MessageTotal for multi-part script reconstruction.
Apply detection heuristics:
- Base64-encoded commands (-EncodedCommand, FromBase64String)
- Download cradles (DownloadString, DownloadFile, Invoke-WebRequest, Net.WebClient)
- AMSI bypass patterns (AmsiUtils, amsiInitFailed)
- Obfuscation indicators (high entropy, tick-mark insertion, string concatenation)
Generate a report with reconstructed scripts, risk scores, and MITRE ATT&CK mappings.

python scripts/agent.py --evtx-file /path/to/PowerShell-Operational.evtx --output ps_analysis.json

Examples

Detect Encoded Command Execution

import base64
if "-encodedcommand" in script_text.lower():
    encoded = script_text.split()[-1]
    decoded = base64.b64decode(encoded).decode("utf-16-le")

Reconstruct Multi-Block Script

Scripts split across multiple 4104 events share a ScriptBlockId. Concatenate blocks ordered by MessageNumber to recover the full script.

---name: analyzing-powershell-script-block-loggingdescription: Parse Windows PowerShell Script Block Logs (Event ID 4104) from EVTX files to detect obfuscated commands, encoded payloads, and living-off-the-land techniques. Uses python-evtx to extract and reconstruct multi-block scripts, applies entropy analysis and pattern matching for Base64-encoded commands, Invoke-Expression abuse, download cradles, and AMSI bypass attempts.license: Apache-2.0---# Analyzing PowerShell Script Block Logging## When to Use- When investigating security incidents that require analyzing powershell script block logging- 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- Familiarity with security operations concepts and tools- Access to a test or lab environment for safe execution- Python 3.8+ with required dependencies installed- Appropriate authorization for any testing activities## Instructions1. Install dependencies: `pip install python-evtx lxml`2. Collect PowerShell Operational logs: `Microsoft-Windows-PowerShell%4Operational.evtx`3. Parse Event ID 4104 entries using python-evtx to extract ScriptBlockText, ScriptBlockId, and MessageNumber/MessageTotal for multi-part script reconstruction.4. Apply detection heuristics: - Base64-encoded commands (`-EncodedCommand`, `FromBase64String`) - Download cradles (`DownloadString`, `DownloadFile`, `Invoke-WebRequest`, `Net.WebClient`) - AMSI bypass patterns (`AmsiUtils`, `amsiInitFailed`) - Obfuscation indicators (high entropy, tick-mark insertion, string concatenation)5. Generate a report with reconstructed scripts, risk scores, and MITRE ATT&CK mappings.```bashpython scripts/agent.py --evtx-file /path/to/PowerShell-Operational.evtx --output ps_analysis.json```## Examples### Detect Encoded Command Execution```pythonimport base64if "-encodedcommand" in script_text.lower(): encoded = script_text.split()[-1] decoded = base64.b64decode(encoded).decode("utf-16-le")```### Reconstruct Multi-Block ScriptScripts split across multiple 4104 events share a `ScriptBlockId`. Concatenate blocks ordered by `MessageNumber` to recover the full script.

Frequently asked questions