Open Source Intelligence (OSINT) in Cybersecurity: Protect Your Organization from Emerging Threats

In today’s world, the amount of publicly accessible information is surprisingly huge. Social media updates, exposed credentials, and misconfigured servers contribute to a digital landscape open to exploitation. 

In April 2024, 5.3 billion data records were exposed across 652 publicly disclosed breaches. Cyber attackers constantly exploit this exposed data to plan and execute attacks. And without knowing what’s publicly visible, organizations remain vulnerable. 

This is where open-source intelligence (OSINT) comes into play. It’s the proactive process of scanning your digital presence before someone else does and fixing exposed credentials, unsecured code, or metadata that attackers could exploit. 

Understanding what OSINT is forms the foundation, but how exactly is open source intelligence leveraged practically in cybersecurity? Let's explore how OSINT is actively used to detect threats, prevent cyberattacks, and strengthen your organization's defense strategies.

What is Open Source Intelligence?

OSINT is the process of collecting and analyzing publicly available data from sources like websites, forums, code repositories, DNS records, metadata, and social media to generate threat intelligence. 

OSINT platforms continuously monitor for signs such as domain mentions or login leaks to detect intrusions, malware activity, and other threats. This helps organizations strengthen their defences, investigate incidents, and receive early warnings of cyber risks.

Initially developed for military and intelligence operations, OSINT is now widely used across business and government sectors, with nearly half of it focused on cybersecurity.

How is Open Source Intelligence Used?

OSINT extends beyond traditional cybersecurity and serves as a powerful tool for threat detection, investigation, and situational awareness across multiple domains. Let’s look at some key scenarios where OSINT proves valuable:

• Cybersecurity monitoring OSINT tools, like those integrated into cybersecurity solutions, track online forums, paste sites, and dark web conversations to identify exposed credentials, malware breaches, and phishing campaigns.

• Government & law enforcement agencies use OSINT to monitor criminal activity, trace extremist communications, and locate missing individuals using open data. 

• Corporate security & brand protection organizations rely on OSINT to detect brand impersonation, phishing websites, and unauthorized IT infrastructure by analysing public IPs and DNS records. It also provides insight into public sentiment during crises or controversies.

• Fraud detection & financial investigations, financial institutions monitor online marketplaces and forums to identify scams, illegal transactions, and identity theft by cross-referencing names, addresses, and transaction data.  

What Qualifies as “Open Source” in Cybersecurity?   

In cybersecurity, "open source" means information that anyone can legally find online without needing special access or permissions. Basically, if it's publicly available like social media posts, websites, or online records, it's considered open source. Any data that is lawfully accessed online is considered open source.

These can be:

• Domain and DNS data: WHOIS records, IP geolocation, DNS registrations, or passive DNS histories
• Public code repositories: GitHub, GitLab, or Bit-bucket projects
• Internet scanning indexes: Shodan or Censys data showing open ports, SSL certificates et al.
• Social media and forums: Public LinkedIn profiles, X(Twitter) and Facebook posts, and Reddit or Telegram threads mentioning your organization
• Corporate filings and news: Business registry entries, SEC filings, press releases, patents, and legal documents
• Paste sites and crime forums: Public dumps of credentials or data leaks
• Unsecured cloud storage: Files accidentally exposed in cloud buckets or public shares

These sources might not make sense by themselves, but when put together, they can provide a meticulous image of your company.   

How is OSINT Used in Cybersecurity?    

In cybersecurity, OSINT serves both attackers and defenders. Cyber attackers and red-team experts often use OSINT for passive surveillance. They scan LinkedIn and company websites for employee information. They search GitHub for exposed API keys. Attackers use Shodan to spot unpatched servers. They also rely on tools like theHarvester to find subdomains and company email addresses. 

These tactics enable intruders to chart an organization's vulnerabilities without breaching the target network, thereby evading detection.  

Security teams set up continuous OSINT monitoring to detect indicators of compromise and external threats. Some use cases include:  

• Leaked credential detection
• brand impersonation alerts
• Shadow it discovery
• Threat infrastructure attribution
• Third-party risk assessment

In practice, OSINT provides security operations with timely threat intelligence and critical context. For instance, if OSINT uncovers discussions about a new exploit targeting Microsoft Exchange, a Security Operations Center (SOC) can proactively apply patches. Since attackers rely on the same publicly available data, OSINT levels the playing field by giving defenders access to the same intelligence that cyber threats exploit

Key OSINT Tools in Cybersecurity Operations  

Security teams rely on specialized OSINT platforms to sift through the flood of public data. Fittingly, many of these platforms are free or open source, mirroring the open and freely accessible nature of the information they analyze:

• Shodan: A search engine that reveals exposed servers, webcams, open ports, and vulnerable devices across the Internet
• theHarvester: Scrapes emails, domains, subdomains, and employee names from public sources to build social engineering targets
• Google Dorking: Uses advanced Google queries to uncover sensitive files, login pages, or internal documents accidentally indexed by search engines
• FOCA: Extracts hidden metadata (e.g., usernames, file paths) from documents found online
• Recon-ng: A modular OSINT tool used to gather, process, and pivot between different data types like IPs, emails, and domains, often used in the early stages of a breach
• Censys: Scans and indexes internet-facing devices and SSL certificates; used to detect exposed infrastructure and expired certs
• SpiderFoot: Automates OSINT collection across 100+ data sources to reveal vulnerabilities, breaches, and digital footprints
• Maltego: Visualizes connections between domains, IPs, infrastructure, and individuals, often used in threat attribution and investigation
• Have I Been Pwned (HIBP): Tracks breached credentials and notifies organizations of exposed user accounts
• SecurityTrails: Used for DNS history, malware scanning, and identifying tech stacks that are essential for asset discovery and threat correlation

Teams combine various tools to suit their needs. A standard process may involve using SpiderFoot or Maltego for initial reconnaissance, followed by in-depth analysis with Shodan or Censys on specific targets, along with Google Dorks and theHarvester for focused research.

OSINT and Third-Party Risks    

Third-party risk management (TPRM) is a critical area where OSINT provides immense value. When you do business with vendors, partners, or suppliers, their security weaknesses can become your problem. 

As many breaches have shown, attackers often target smaller partners to get to larger firms. OSINT allows organizations to evaluate the security posture of third parties using only public data. In fact, many vendor security rating services and cyber insurance assessments begin with OSINT collection on the target company.

Open-source intelligence has become a fundamental part of vendor and supply-chain risk management. Using open-source intelligence, security teams can investigate a vendor’s internet footprint for red flags. 

For example, OSINT techniques can reveal if a supplier has exposed credentials or data floating around on the web. Analysts might find an employee’s email and see that its password was part of a leaked database posted online, indicating the vendor has a breach or poor password hygiene. OSINT can also uncover unpatched systems or outdated software used by a third party.

A practical example of OSINT in third-party risk is the partnership between Atlas Systems and Tenable to offer attack surface scans to any company. Through this collaboration, organizations can run instant external scans (web application security, network exposure, vulnerability checks) to understand their security exposure, including that of their third parties, in a self-service mode. The scan results include finding an open port or outdated software on a vendor’s site, and help highlight risks that need addressing. Such initiatives show how publicly accessible data (ports, web pages, etc.) is leveraged to manage third-party cyber risk continuously.

In short, OSINT transforms publicly accessible indicators like a vendor's exposed service into an early warning sign to prevent a supply-chain attack. As regulations and cyber insurance requirements become more stringent, incorporating OSINT into vendor risk assessments has become a standard practice for many large corporations.

Real-World Examples of OSINT in Action

From online sleuthing to patching vulnerable servers before ransomware strikes, OSINT shows how much you can learn by looking at what’s already public. The incidents below demonstrate that with the right free tools, you can stop real-world threats in their tracks.

Best Practices for OSINT in Cybersecurity    

Even though the sources are public, analysts must navigate legal, ethical, and operational pitfalls while using OSINT. Key best practices include:

• Stay legal and ethical
  You should only access data that you are permitted to view, staying within the bounds of the law and ethics. Refrain from attempting to bypass login screens, hacking into password-protected accounts, or impersonating identities.

• Respect terms of service
  Always verify a site's Terms of Service to ensure your methods (such as web scraping) do not contravene its rules.

• Define your investigation scope
  Before initiating an OSINT investigation, determine the specific information you're seeking. Are you searching for compromised credentials, mapping employee networks, or tracking brand mentions?

• Revisit and refine targets
  Periodically review and refine your scope as new targets arise.
  

• Validate your findings
  Verify and authenticate information: Not all online data is trustworthy. OSINT analysts should compare any findings with multiple sources to ensure accuracy.

• Document the verification process
  Always approach unverified intelligence with caution and document your verification process for auditing purposes.
  

• Secure sensitive intelligence
  Although OSINT relies on public sources, the intelligence collected can be highly sensitive. Securely store discoveries and only disseminate them to teams that require access. 

• Establish an OSINT policy
  Establish an OSINT policy that specifies approved tools and data handling procedures, ensuring adherence to corporate and legal regulations.

• Automate wisely
  Leveraging APIs or scripts can streamline the process, but be aware that data sources are constantly evolving. Social media platforms may restrict or ban scrapers, and malicious actors often shift to new, concealed platforms.

• Keep your toolkit current
  Regularly assess and update your tools and techniques.

By following these best practices your company can transform OSINT into a trustworthy component of its security arsenal. To learn more about the evolving role of OSINT, check out the latest cybersecurity trends.

Stay Ahead of Threats with ComplyScore®  

Open-source intelligence has become a cornerstone of risk monitoring and mitigation in vendor and supply-chain security.

While attackers scan the internet for your weaknesses, ComplyScore® scans it for your protection. Designed for modern security teams, ComplyScore® is a cybersecurity risk management platform that helps organizations identify, monitor, and respond to digital exposure in real-time.

By consolidating public threat intelligence into a single, actionable view, ComplyScore® goes beyond detection. It helps you understand what’s at risk, why it matters, and how to fix it.

Explore ComplyScore® to uncover risks, reduce attack surfaces, and build a proactive, OSINT-powered security posture.

FAQs 

1. What are the best OSINT tools for cybersecurity?

Some of the best OSINT tools for cybersecurity include Shodan, which scans the internet for exposed devices and services; Maltego, which maps connections between entities like domains and IPs; and SpiderFoot, an automation tool that collects threat data across hundreds of sources. 

2. Is OSINT legal to use in corporate cybersecurity?

Yes, OSINT is legal when used responsibly and while following the guidelines set by  regulatory bodies. It involves collecting publicly accessible information without breaking into systems or bypassing security measures. In a corporate setting, OSINT supports threat detection and third party risk management while complying with laws like GDPR and CCPA.

3. How does OSINT differ from traditional threat intelligence?

OSINT is a subset of threat intelligence that focuses exclusively on publicly available data, such as websites, forums, and social media. In contrast, traditional threat intelligence may also include private, classified, or proprietary sources, such paid threat feeds, and internal incident logs. OSINT is typically low-cost, widely accessible, and useful for early threat detection, whereas traditional intelligence offers deeper insights into adversary behavior and infrastructure..

4. How can OSINT help prevent phishing attacks?

OSINT helps prevent phishing by identifying lookalike domains, spoofed email addresses, and fake social media profiles that imitate legit brands. Security teams monitor domain registrations, SSL certificates, and public DNS records to identify impersonation attempts before they're used in phishing campaigns. 

5. Can OSINT be used for insider threat detection?

Yes, OSINT can also be used to detect insider threat, this can be achieved by monitoring public social media posts, developer forums, and data leak sites for signs of internal data being shared externally. Employees may unintentionally expose sensitive information through public GitHub commits, online resumes, or job discussion boards.