performing-malware-hash-enrichment-with-virustotal

name	performing-malware-hash-enrichment-with-virustotal
description	Enrich malware file hashes using the VirusTotal API to retrieve detection rates, behavioral analysis, YARA matches, and contextual threat intelligence for incident triage and IOC validation.
domain	cybersecurity
subdomain	threat-intelligence
tags	["virustotal","malware-analysis","hash-enrichment","ioc","threat-intelligence","triage","api","detection"]
version	1.0
author	mahipal
license	Apache-2.0
nist_csf	["ID.RA-01","ID.RA-05","DE.CM-01","DE.AE-02"]
mitre_attack	["T1591","T1592","T1593","T1589","T1027"]
source	https://github.com/mukul975/Anthropic-Cybersecurity-Skills
source_commit	04450304b12645cb2b974ab96d28c0664758a88d
note	Vendored verbatim from an external Apache-2.0 security-skill library, pinned by commit. Exceeds the internal 300-line skill guideline (agent-code-constraints.md) -- kept as-is because this is vendored reference material (forensics/threat-intel procedure), not Yana AI-authored content, and trimming would damage technical accuracy.

Performing Malware Hash Enrichment with VirusTotal

Overview

VirusTotal is the world's largest crowdsourced malware corpus, scanning files with 70+ antivirus engines and providing behavioral analysis, YARA rule matches, network indicators, and community intelligence. This skill covers using the VirusTotal API v3 to enrich file hashes (MD5, SHA-1, SHA-256) with detection verdicts, sandbox reports, related indicators, and contextual intelligence for SOC triage, incident response, and threat intelligence enrichment workflows.

When to Use

• When conducting security assessments that involve performing malware hash enrichment with virustotal
• When following incident response procedures for related security events
• When performing scheduled security testing or auditing activities
• When validating security controls through hands-on testing

Prerequisites

• Python 3.9+ with vt-py (official VirusTotal Python client) or requests
• VirusTotal API key (free tier: 4 requests/minute, 500/day; premium for higher limits)
• Understanding of file hash types: MD5, SHA-1, SHA-256
• Familiarity with AV detection naming conventions
• STIX 2.1 knowledge for IOC representation

Key Concepts

VirusTotal API v3

The API provides RESTful endpoints for file reports (/files/{hash}), URL scanning, domain reports, IP address intelligence, and advanced hunting with VirusTotal Intelligence (VTI). Each file report includes detection results from 70+ AV engines, behavioral analysis from sandboxes, YARA rule matches, sigma rule matches, file metadata (PE headers, imports, sections), network indicators (contacted IPs, domains, URLs), and community votes and comments.

Hash Enrichment Workflow

The typical enrichment flow is: receive hash from alert/EDR -> query VT API -> parse detection ratio -> extract behavioral indicators -> correlate with existing intelligence -> make triage decision. The API returns a last_analysis_stats object with malicious, suspicious, undetected, and harmless counts.

Pivoting from Hashes

VirusTotal enables pivoting from a single hash to related intelligence: similar files (ITW/in-the-wild samples), contacted domains and IPs (C2 infrastructure), dropped files, embedded URLs, YARA rule matches, and threat actor attribution through crowdsourced intelligence.

Workflow

Step 1: Query VirusTotal for Hash Report

import vt
 json
 hashlib
 datetime  datetime

 :
     ():
        .client = vt.Client(api_key)

     ():
        
        :
            file_obj = .client.get_object()
            stats = file_obj.last_analysis_stats
            report = {
                : file_hash,
                : file_obj.sha256,
                : file_obj.sha1,
                : file_obj.md5,
                : (file_obj, , ),
                : (file_obj, , ),
                : ((file_obj, , )),
                : ((file_obj, , )),
                : {
                    : stats.get(, ),
                    : stats.get(, ),
                    : stats.get(, ),
                    : stats.get(, ),
                },
                : ,
                : (file_obj, , {}),
                : (file_obj, , []),
                : (file_obj, , []),
            }
            total_engines = (stats.values())
            mal_count = stats.get(, )
            report[] = (
                  mal_count > total_engines * 
                   mal_count > total_engines * 
                   mal_count > total_engines * 
                   mal_count > 
                 
            )
            (
                  )
             report
         vt.error.APIError  e:
            ()
             

     ():
        
        :
            behaviors = .client.get_object()
            behavior_data = {
                : [],
                : [],
                : [],
                : [],
                : [],
                : [],
                : [],
            }
             sandbox  (behaviors, , []):
                attrs = sandbox.get(, {})
                behavior_data[].extend(
                    attrs.get(, []))
                behavior_data[].extend(
                    [f.get(, )  f  attrs.get(, [])])
                behavior_data[].extend(
                    [r.get(, )  r  attrs.get(, [])])
                behavior_data[].extend(
                    [d.get(, )  d  attrs.get(, [])])
                behavior_data[].extend(
                    attrs.get(, []))
             behavior_data
         Exception  e:
            ()
             {}

     ():
        .client.close()


enricher = VTEnricher()
report = enricher.enrich_hash()
(json.dumps(report, indent=, default=))
enricher.close()