What it does. Detect PowerShell Empire post-exploitation framework artifacts in Windows Script Block Logging (Event ID 4104) and Module Logging (Event ID 4103), including the default launcher string, Base64-encoded WebClient/FromBase64String payloads, known module invocations (Invoke-Mimikatz, Invoke-Kerberoast), and staging URL patterns. Use when hunting for or confirming Empire C2 activity in Windows event logs. Part of mukul975/Anthropic-Cybersecurity-Skills (817 security skills) (mukul975/Anthropic-Cybersecurity-Skills).

Install

• npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill analyzing-powershell-empire-artifacts, or copy the skill folder into ~/.claude/skills/analyzing-powershell-empire-artifacts/.
• Raw file: curl -sL https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/HEAD/skills/analyzing-powershell-empire-artifacts/SKILL.md

SKILL.md (verbatim)

name: analyzing-powershell-empire-artifacts
description: Detect PowerShell Empire post-exploitation framework artifacts in Windows Script Block Logging (Event ID 4104) and Module Logging (Event ID 4103), including the default launcher string, Base64-encoded WebClient/FromBase64String payloads, known module invocations (Invoke-Mimikatz, Invoke-Kerberoast), and staging URL patterns. Use when hunting for or confirming Empire C2 activity in Windows event logs.
domain: cybersecurity
subdomain: threat-hunting
tags:
- PowerShell-Empire
- threat-hunting
- Script-Block-Logging
- base64
- stager
- C2
- MITRE-ATT&CK
- T1059.001
- forensics
version: '1.0'
author: mahipal
license: Apache-2.0
d3fend_techniques:
- Executable Denylisting
- Execution Isolation
- File Metadata Consistency Validation
- Content Format Conversion
- File Content Analysis
nist_ai_rmf:
- GOVERN-1.1
- MEASURE-2.7
- MANAGE-3.1
nist_csf:
- DE.CM-01
- DE.AE-02
- DE.AE-07
- ID.RA-05
mitre_attack:
- T1059.001
- T1071.001
- T1003.001
- T1558.003
- T1027.010

Analyzing PowerShell Empire Artifacts

Overview

PowerShell Empire is a post-exploitation framework consisting of listeners, stagers, and agents. Its artifacts leave detectable traces in Windows event logs, particularly PowerShell Script Block Logging (Event ID 4104) and Module Logging (Event ID 4103). This skill analyzes event logs for Empire's default launcher string (powershell -noP -sta -w 1 -enc), Base64 encoded payloads containing System.Net.WebClient and FromBase64String, known module invocations (Invoke-Mimikatz, Invoke-Kerberoast, Invoke-TokenManipulation), and staging URL patterns.

When to Use

• When investigating security incidents that require analyzing powershell empire artifacts
• 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

• Python 3.9+ with access to Windows Event Log or exported EVTX files
• PowerShell Script Block Logging (Event ID 4104) enabled via Group Policy
• Module Logging (Event ID 4103) enabled for comprehensive coverage

Key Detection Patterns

1. Default launcher — powershell -noP -sta -w 1 -enc followed by Base64 blob
2. Stager indicators — System.Net.WebClient, DownloadData, DownloadString, FromBase64String
3. Module signatures — Invoke-Mimikatz, Invoke-Kerberoast, Invoke-TokenManipulation, Invoke-PSInject, Invoke-DCOM
4. User agent strings — default Empire user agents in HTTP listener configuration
5. Staging URLs — /login/process.php, /admin/get.php and similar default URI patterns

Output

JSON report with matched IOCs, decoded Base64 payloads, timeline of suspicious events, MITRE ATT&CK technique mappings, and severity scores.

Other files in this skill

• LICENSE
• references/api-reference.md
• scripts/agent.py

references/api-reference.md (verbatim)

PowerShell Empire Artifact Detection Reference

Enable Script Block Logging (GPO)

Computer Configuration > Administrative Templates > Windows Components >
Windows PowerShell > Turn on PowerShell Script Block Logging: Enabled

Registry: HKLM\SOFTWARE\Policies\Microsoft\Windows\PowerShell\ScriptBlockLogging

• EnableScriptBlockLogging = 1

Enable Module Logging (GPO)

Computer Configuration > Administrative Templates > Windows Components >
Windows PowerShell > Turn on Module Logging: Enabled
Module Names: *

Key Event IDs

Default Empire Launcher Pattern

powershell -noP -sta -w 1 -enc <Base64-payload>

Launcher Flags

Empire Stager IOC Patterns

Empire Module Signatures

Default Empire Staging URIs

/login/process.php
/admin/get.php
/admin/news.php
/news.php
/login/process.jsp

Splunk Detection Query

index=wineventlog source="WinEventLog:Microsoft-Windows-PowerShell/Operational" EventCode=4104
| where match(ScriptBlockText, "(?i)system\.net\.webclient") AND match(ScriptBlockText, "(?i)frombase64string")
| stats count by Computer, UserID, ScriptBlockText

Elastic KQL Detection

event.code: "4104" AND powershell.file.script_block_text: (*System.Net.WebClient* AND *FromBase64String*)

MITRE ATT&CK Mapping

• T1059.001 — Command and Scripting Interpreter: PowerShell
• T1071.001 — Application Layer Protocol: Web Protocols
• T1027 — Obfuscated Files or Information
• T1105 — Ingress Tool Transfer

Back to mukul975/Anthropic-Cybersecurity-Skills (817 security skills) or Agent skills.