detecting-fileless-malware-techniques

name	detecting-fileless-malware-techniques
description	Detects and analyzes fileless malware that operates entirely in memory using PowerShell, WMI, .NET reflection, registry-resident payloads, and living-off-the-land binaries (LOLBins) without writing traditional executable files to disk. Activates for requests involving fileless threat detection, in-memory malware investigation, LOLBin abuse analysis, or WMI persistence examination. . Use when working with detecting fileless malware techniques.
domain	cybersecurity
tags	["malware","fileless","LOLBins","memory-analysis","detection"]
subdomain	malware-analysis
version	1.0.0
author	oyi77
license	Apache-2.0
d3fend_techniques	["Executable Denylisting","Execution Isolation","File Metadata Consistency Validation","Content Format Conversion","File Content Analysis"]
nist_csf	["DE.AE-02","RS.AN-03","ID.RA-01","DE.CM-01"]

Detecting Fileless Malware Techniques

Overview

Cybersecurity skill for detecting fileless malware techniques. Follows industry best practices and security standards.

When to Use

Trigger phrases:

• "detecting fileless malware techniques"

• "Detects and analyzes fileless malware that operates entirely in memory using Pow"

• EDR alerts indicate suspicious behavior from trusted system binaries (PowerShell, mshta, wmic, regsvr32)

• Investigating attacks that leave no traditional malware files on disk

• Analyzing WMI event subscriptions, registry-stored payloads, or scheduled task abuse for persistence

• Building detection rules for LOLBin (Living Off the Land Binary) abuse in enterprise environments

• Memory forensics reveals malicious code but no corresponding files exist on the filesystem

Do not use for traditional file-based malware; standard static and dynamic analysis methods are more appropriate for disk-resident malware.

When NOT to Use

• When you lack proper authorization for testing
• For production systems without change management
• When the task requires legal or compliance expertise beyond technical scope

Prerequisites

• Sysmon installed and configured with comprehensive logging (process creation, WMI events, registry changes)
• PowerShell Script Block Logging and Module Logging enabled
• Volatility 3 for memory forensics of fileless malware artifacts
• Process Monitor (ProcMon) for real-time system activity monitoring
• Windows Event Log access with adequate retention policies
• Autoruns for identifying persistence mechanisms

Workflow

# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: ) -> :
     {k: re.findall(v, text)  k, v  IOC_PATTERNS.items()}