Free Threat Intel

Comprehensive Summary & Cheat Sheet: Free Threat Intelligence Platforms & Vulnerability Databases

This guide provides a detailed overview and quick-reference cheat sheet for major free threat intelligence platforms—including GreyNoise—and free vulnerability databases maintained by organizations such as the FBI, CISA, and MITRE. It covers platform features, integration capabilities, and technical standards to help you leverage these resources for cybersecurity operations.


1. Free Threat Intelligence Platforms

1.1 GreyNoise

  • Purpose: Filters out internet background noise to help security teams focus on real threats.

  • Key Features:

    • Real-time intelligence on mass internet scan and attack activity.

    • NOISE and RIOT databases for tagging threats and labeling common business services.

    • Reduces alert volume by ~25% by filtering benign internet noise.

    • Out-of-the-box integrations with SIEM, SOAR, TIP, and other security tools.

    • Community API (free): Basic IP lookups to check if an IP is associated with known noise or malicious activity.

    • Research Community Program: Free, non-commercial access to premium features for students, educators, and researchers.

    • No setup fees for free or paid tiers .


1.2 Malware Information Sharing Platform (MISP)

  • Purpose: Open-source platform for sharing structured threat intelligence.

  • Key Features:

    • Supports data models, threat feeds, event management, and sharing.

    • Automatic correlation of attributes and indicators.

    • Exports in XML, JSON, OpenIOC, STIX formats for interoperability.

    • Enhances detection and response through collaborative intelligence sharing .


1.3 AlienVault Open Threat Exchange (OTX)

  • Purpose: Collaborative platform for real-time threat intelligence sharing.

  • Key Features:

    • Pulse system for detailed threat reports (IOCs, references).

    • Continuously updated with latest malware, vulnerabilities, and threat data.

    • Fosters community-driven threat awareness and response .


1.4 Open Cyber Threat Intelligence Platform (OpenCTI)

  • Purpose: Manages and analyzes threat intelligence from multiple sources.

  • Key Features:

    • Unified framework for storing, organizing, and correlating threat knowledge.

    • Supports STIX and TAXII standards for data sharing.

    • Facilitates integration with other platforms and tools .


1.5 Yeti

  • Purpose: Organizes observables, IOCs, and threats for actionable intelligence.

  • Key Features:

    • Collaborative environment for analysts.

    • Automated imports from various feeds.

    • Robust API for automation and customization .


1.6 Cuckoo Sandbox

  • Purpose: Malware analysis and reporting in a sandboxed environment.

  • Key Features:

    • Analyzes multiple file types (DLL, PDF, Office, URLs, etc.).

    • Generates detailed behavioral reports for suspicious files .


2. Free Vulnerability Databases by Major Organizations

2.1 CISA (Cybersecurity and Infrastructure Security Agency)

  • Known Exploited Vulnerabilities (KEV) Catalog:

    • Regularly updated list of vulnerabilities actively exploited in the wild.

    • As of June 2023, included 896 high-risk vulnerabilities.

    • Focuses on widely used systems (Windows, macOS, Linux).

  • Coordinated Vulnerability Disclosure (CVD) Program:

    • Collects and validates vulnerability reports from public and internal sources.

    • In FY24, coordinated 845 cases and produced 427 advisories.

  • Risk and Vulnerability Assessment (RVA):

    • One-on-one engagements to identify and mitigate organizational weaknesses.

  • Public Tools:

    • Open-source tools (e.g., Anchore) to check environments for KEV-listed vulnerabilities .


2.2 MITRE

  • Common Vulnerabilities and Exposures (CVE) Program:

    • Standardized identifiers for publicly disclosed vulnerabilities.

    • Managed by MITRE, sponsored by DHS/CISA.

    • CVE List is a global reference for vulnerability management .

  • MITRE ATT&CK Framework:

    • Knowledge base of adversary tactics and techniques.

    • Used for threat modeling, detection, and response.

  • MITRE-Cyber-Security-CVE-Database (2025):

    • Aggregates CVE data from MITRE, NVD, CISA KEV, CVEDetails, Tenable, and more.

    • Open-source, supports community contributions, and automated updates.

    • Data available in JSON for easy integration .


2.3 FBI

  • Role: Primarily focused on cybercrime investigation, intelligence sharing, and response.

  • Key Resources:

    • Internet Crime Complaint Center (IC3): Collects public reports of internet crime.

    • National Cyber Investigative Joint Task Force (NCIJTF): Multi-agency task force for cyber threat response.

    • CyWatch: 24/7 operations center for incident tracking and communication.

    • Asset Forfeiture Program: Seizes assets from cybercriminals and compensates victims.

  • Vulnerability Database: The FBI does not maintain a public vulnerability database but collaborates with CISA and other agencies for alerts and advisories .


3. Integration Capabilities & Technical Standards

  • APIs: Most platforms (including GreyNoise, MISP, OpenCTI) offer APIs for integration with SIEM, SOAR, TIP, and other security tools.

  • STIX/TAXII Support:

    • STIX: Structured language for describing cyber threats (STIX 2.x uses JSON; STIX 1.x uses XML).

    • TAXII: Protocol for secure, automated exchange of threat intelligence.

    • Widely supported by platforms for interoperability and automated sharing .

  • SIEM Integration: Platforms can feed threat intelligence and vulnerability data into SIEMs for real-time alerting and correlation.

  • DevSecOps Integration: Tools can be embedded in CI/CD pipelines for automated vulnerability detection .


4. Quick-Reference Cheat Sheet

Platform/Database
Type
Free Tier/Access
Key Features/Notes

GreyNoise

Threat Intelligence

Community API, Research

Filters internet noise, real-time data, SIEM/SOAR integration, free for basic use

MISP

Threat Intelligence

Open-source

Structured sharing, auto-correlation, multi-format export

AlienVault OTX

Threat Intelligence

Free

Community-driven, real-time pulses, IOCs sharing

OpenCTI

Threat Intelligence

Open-source

Unified threat management, STIX/TAXII support

Yeti

Threat Intelligence

Open-source

IOC management, automated feed imports, API

Cuckoo Sandbox

Malware Analysis

Open-source

Sandbox analysis, detailed reports

CISA KEV Catalog

Vulnerability DB

Public

Known exploited vulnerabilities, regular updates

MITRE CVE

Vulnerability DB

Public

Standardized CVE IDs, global reference

MITRE ATT&CK

Threat Framework

Public

Adversary tactics/techniques, detection/response

MITRE-Cyber-Security-CVE

Vulnerability DB

Open-source

Aggregated CVE data, JSON format, community contributions

FBI (IC3, NCIJTF, etc.)

Cybercrime Intel

Public resources

Incident reporting, advisories, no standalone vulnerability DB


5. How to Use These Resources

  • Threat Detection: Integrate threat intelligence feeds (GreyNoise, MISP, OTX) into your SIEM/SOAR for real-time alerting and context enrichment.

  • Vulnerability Management: Regularly consult CISA KEV, MITRE CVE, and MITRE-Cyber-Security-CVE-Database to prioritize patching and remediation.

  • Incident Response: Use FBI advisories and IC3 for reporting and understanding current cybercrime trends.

  • Automation: Leverage APIs and STIX/TAXII support for automated data ingestion and sharing across your security stack.

  • Research & Collaboration: Participate in community programs (e.g., GreyNoise Research Community) and contribute to open-source platforms for collective defense.


This summary and cheat sheet should equip you with a comprehensive understanding of the leading free threat intelligence platforms and vulnerability databases, along with practical guidance for integration and operational use.

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