Active 2024-06-18

ShellSweep

ShellSweeping the evil. PowerShell/Python/Lua tool to detect potential web shells using entropy analysis, machine learning, and YARA rules.

webshell detection hunting entropy security splunk
Quickstart
Get started instantly
git clone https://github.com/splunk/ShellSweep.git && .\ShellSweep\ShellSweep.ps1

The Problem

Web shells are a persistent threat that can be difficult to detect, especially when attackers use obfuscation or encryption. Traditional signature-based detection often misses new variants.

The Solution

ShellSweep uses entropy analysis to detect obfuscated/encrypted code commonly found in web shells. High entropy indicates randomness - a characteristic of malicious payloads. Includes ShellSweep, ShellSweepPlus (with heuristics), and ShellSweepX (with ML and YARA).

Impact

Used by defenders worldwide to identify web shell compromises. The entropy-based approach catches shells that signature-based tools miss.

Overview

ShellSweep is a PowerShell/Python/Lua tool designed to detect potential web shell files using entropy analysis.

How It Works

Entropy measures randomness in data. Obfuscated or encrypted web shells have high entropy compared to normal web files. ShellSweep calculates file entropy and flags suspicious files.

Variants

  • ShellSweep: Core entropy-based detection
  • ShellSweepPlus: Adds heuristics, pattern matching, confidence scoring
  • ShellSweepX: Adds machine learning and YARA rule matching

Supported Extensions

  • .asp, .aspx, .asph, .php, .jsp

Sweep for web shells

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