Automated Malware Analysis with LLM: Integrating YARA, FLOSS, and CAPA

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Sven Rath developed an MCP server that enables Large Language Models (LLMs) like Claude to perform automatic static malware analysis, generating detailed reports in Markdown. The tool integrates:
– YARA (pattern-based malware detection)
– yara-forge (YARA rule generator)
– detect-it-easy (file type identification)
– FLOSS (extracting obfuscated strings)
– capa (identifying malware capabilities)
– PE analysis (IAT, EAT, section headers)

PoC Code: GitHub Link

You Should Know: Key Commands & Tools

1. YARA Rule Generation & Scanning

 Generate YARA rules with yara-forge 
yara-forge -s malware_sample.exe -o custom_rule.yar

Scan malware with YARA 
yara -r custom_rule.yar suspicious_file.exe 

2. FLOSS for String Extraction

 Extract obfuscated strings from malware 
floss -q malware_sample.exe > extracted_strings.txt 

3. CAPA for Malware Capability Analysis

 Analyze malware capabilities 
capa malware_sample.exe -v > capa_report.txt 

4. Detect-It-Easy (DIE) for File Analysis

 Check file type and entropy 
diec -f malware_sample.exe 

5. PE Analysis (IAT/EAT/Sections)

 Using PE Tools (Linux) 
readpe -h malware_sample.exe  Show PE headers 
readpe -i malware_sample.exe  Inspect IAT 
readpe -e malware_sample.exe  Extract EAT 

6. Automating with Python (MCP Server Integration)

import subprocess

def run_floss(file_path): 
result = subprocess.run(["floss", file_path], capture_output=True, text=True) 
return result.stdout

malware_report = run_floss("malware.exe") 
print(malware_report) 

What Undercode Say

Automating malware analysis with LLMs enhances reverse engineering efficiency, especially when combined with tools like YARA, CAPA, and FLOSS. This approach:
– Reduces manual analysis time
– Improves detection accuracy
– Generates structured reports

Future enhancements could include dynamic analysis integration (Cuckoo Sandbox) and AI-powered anomaly detection.

Prediction

  • AI-driven malware analysis will dominate threat intelligence.
  • LLMs will automate 60% of reverse engineering tasks by 2026.

Expected Output:

 Malware Analysis Report (Generated by LLM)

YARA Matches 
- Rule: `Trojan_Generic_01` 
- Detection: `Matching signature found in .text section` 

FLOSS Extracted Strings 
- `"C:\Windows\System32\kernel32.dll"` 
- `"http://malicious-domain.com/payload.exe"` 

CAPA Findings 
- `CAPABILITY: Persistence via Registry Run Key` 
- `CAPABILITY: Network Communication (HTTP)` 

PE Structure 
- Sections: `.text (RX), .data (RW)` 
- IAT Imports: `CreateProcessA, RegSetValueEx` 

Relevant URLs:

References:

Reported By: Sven Rath – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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