extracting-iocs-from-malware-samples

Extracting IOCs from Malware Samples

When to Use

• A malware analysis (static or dynamic) is complete and actionable indicators need to be extracted for defense teams
• Building blocklists for firewalls, proxies, and DNS sinkholes from analyzed samples
• Creating YARA rules, Snort/Suricata signatures, or SIEM detection content from malware artifacts
• Contributing to threat intelligence sharing platforms (MISP, OTX, ThreatConnect)
• Tracking malware campaigns by correlating IOCs across multiple samples

Do not use for IOCs from unverified sources without validation; false positives in blocklists can disrupt legitimate business operations.

Prerequisites

• Python 3.8+ with iocextract, pefile, yara-python libraries installed
• Completed malware analysis report (static analysis, dynamic analysis, or reverse engineering)
• Access to PCAP files, memory dumps, or sandbox reports from the analysis
• MISP instance or STIX/TAXII server for structured IOC sharing
• VirusTotal API key for IOC enrichment and validation
• CyberChef for decoding obfuscated indicators

Workflow

Step 1: Extract File-Based IOCs

Compute hashes and identify file metadata indicators:

# Generate all standard hashes
md5sum malware_sample.exe
sha1sum malware_sample.exe
sha256sum malware_sample.exe

# Generate ssdeep fuzzy hash for similarity matching
ssdeep malware_sample.exe

# Generate imphash (import hash) for PE files
python3 -c "
import pefile
pe = pefile.PE('malware_sample.exe')
print(f'Imphash: {pe.get_imphash()}')
"

# Generate TLSH (Trend Micro Locality Sensitive Hash)
python3 -c "
import tlsh
with open('malware_sample.exe', 'rb') as f:
    h = tlsh.hash(f.read())
print(f'TLSH: {h}')
"

# Compile file metadata IOCs
python3 << 'PYEOF'
import pefile
import os
import hashlib
import datetime

pe = pefile.PE("malware_sample.exe")

print("FILE IOCs:")
with open("malware_sample.exe", "rb") as f:
    data = f.read()
    print(f"  MD5:        {hashlib.md5(data).hexdigest()}")
    print(f"  SHA-1:      {hashlib.sha1(data).hexdigest()}")
    print(f"  SHA-256:    {hashlib.sha256(data).hexdigest()}")
    print(f"  File Size:  {len(data)} bytes")

ts = pe.FILE_HEADER.TimeDateStamp
print(f"  Compile:    {datetime.datetime.utcfromtimestamp(ts)} UTC")
print(f"  Imphash:    {pe.get_imphash()}")
PYEOF