8 Open-Source Intelligence (OSINT) Tools for Penetration Testing

Open-source intelligence (OSINT) refers to gathering information from publicly available sources to support intelligence analysis. Thanks to the wealth of data available on the internet today, OSINT enables the collection of immense amounts of information that can be extremely useful during penetration testing engagements.

In this comprehensive guide, we will explore 8 powerful OSINT tools that penetration testers can leverage to thoroughly research target organizations, identify security vulnerabilities, expand access once inside a network, and more.

An Introduction to OSINT for Penetration Testing

Before diving into the tools, let’s briefly discuss how OSINT applies to penetration testing.

OSINT gathering is a critical first step of reconnaissance in the penetration testing process. By scouring publicly available data sources ranging from WHOIS records to social media sites, pentesters build a body of knowledge on the target organization. This includes information like:

• IP address ranges
• Domain names
• Technologies in use
• Employee names/email addresses
• Exposed assets or databases
• Potential vulnerabilities

Armed with OSINT, pentesters can then strategically target security testing towards high-risk areas, launch informed social engineering attacks, and expand access across wider segments of the network. Defenders also leverage OSINT to understand cyber threats facing the organization.

The tools featured in this guide excel at gathering the types of data needed for penetration tests and cybersecurity use cases. With further ado, let’s explore them.

1. Criminal IP

Criminal IP is an OSINT search engine focused specifically on cyber threat intelligence. It enables searching across over 4.2 billion IP addresses to uncover data like associated domains/subdomains, open ports, technologies used, exposure risks, and known vulnerabilities.

A few key facts about Criminal IP:

• Created by Intrigue Core SRL to power cyber threat intel and investigations
• Offers a freemium model with limited searches for free accounts
• Paid plans unlock unlimited searches, API access, data exports, and more
• High accuracy threat scores assessing risk levels of IPs and domains surfaced

For penetration testers, Criminal IP excels at discovering internet-exposed assets and vulnerabilities to target. For example, searches can reveal databases left unprotected without authentication or devices with known remote access flaws.

Example dashboard views provide handy overviews of risks and security gaps across entire network ranges. The tool’s breadth of coverage across IP space and accuracy of results has made it popular for cybersecurity use cases.

Key Strengths: Scale/coverage, accuracy of risk scoring algorithms, focus specifically on security intel

Limitations: No automated correlation of connected assets, steeper learning curve than other tools

2. NexVision

NexVision provides an AI-powered OSINT solution offering unique access to restricted or hard-to-reach sources like the dark web, social media sites, and technical data. Developed by former NSA cyberspies, NexVision is used by government agencies and financial institutions to power security investigations and cyber intelligence.

NexVision’s key capabilities include:

• Automated collection/categorization of unstructured data from over 500 sources
• Machine learning to link related pieces of information and reduce false positives
• Custom keyword alerts to monitor online targets
• Social media monitoring with geolocation tracing
• Searchable interface to analyze results

For penetration testing, NexVision can uncover invaluable data that would otherwise be difficult or require special access privileges to obtain. Dark web sources offer potential underground chatter on vulnerabilities or plans by hacktivist groups. Meanwhile, tapping into leaked databases and technical data enables discovering user credentials, software flaws, misconfigured systems, and more to target.

The tool does have a steeper learning curve compared to others featured. However, in return, NexVision provides unparalleled access to restricted OSINT and powerful automation to improve productivity. These unique capabilities make NexVision a top choice for government/military cyber teams. But scaled pricing also makes it viable for corporate information security groups.

Key Strengths: Coverage of hard-to-access sources, ML automation of workflows, dark web search capabilities

Limitations: Steeper learning curve than other tools

3. Social Links

Social Links offers an enterprise-grade OSINT solution focused on flexibility, automation, and data privacy. Leveraging machine learning algorithms, the platform provides users unmatched control to gather precisely the data needed from over 500 sources including social networks, messengers, blockchains ledgers, forums, and dark web sites.

Why Social Links stands apart for penetration testing:

• 1000+ pre-built search queries, many leveraging ML for accuracy
• Options to enrich, filter, analyze, and visualize data
• On-premise deployment options to assure privacy
• Customization services tailored to client data needs

Social Links enables digging deeper into social relationships of an organization, while leveraging automation to connect findings to individuals. For example, an attacker can quickly map out key executives on LinkedIn, gathering details on past employers, interests, contact info, and habits to launch personalized phishing lures. Usernames exposed in breaches can be checked across sites to pivot attack avenues as well.

For teams that need rigorous data control and customization options, Social Links provides enterprise managed services. This includes tailored ML models trained to client data types for unmatched accuracy. SL analysts can also deliver customized engagement reports documenting findings.

Key Strengths: Customization options, automation features, enterprise offerings and services

Limitations: Requires large up-front investment for full-scale implementation

4. Shodan

Shodan operates a powerful internet search engine used by cybersecurity professionals, academic researchers, and hackers alike. Rather than searching websites, Shodan indexes internet-connected devices and systems ranging from building access controls to industrial equipment. It provides an invaluable tool for discovering overlooked assets and connections during penetration testing.

Examples of how penetration testers can leverage Shodan:

• Finding forgotten devices or hardware using default passwords
• Identifying improperly configured networks or firewalls
• Targeting unpatched systems relying on vulnerable versions of Apache/OpenSSL/SSH, etc.
• Pivoting through interconnected systems across supply chains

Shodan offers a $50 monthly membership providing plenty of lookups for individuals. The tool also has free tiers albeit with very limited searches. Ultimately over 90% of information indexed by Shodan maps back to paying enterprise customers.

Thanks to the immense range of internet-connected devices and systems indexed by Shodan, it provides penetration testers immense reconnaissance capabilities–shaving hours off the information gathering process. Even for attackers, Shodan can yield enough intel to immediately launch targeted exploits rather than relying on traditional spraying attacks.

Key Strengths: Breadth of internet-connected systems indexed, valuable reconnaissance for physical systems/IOT networks

Limitations: Results skewed towards paying enterprise customer data sources

5. Google Dorks

Google Dorks provide specially crafted search queries enabling the discovery of sensitive files, data leaks, vulnerabilities, and other information disclosures using Google’s industry-leading web search capabilities. Since Google indexes immense spans of content across open internet sites and password-protected pages, Google Dorks provide a prime mechanism for uncovering hidden attack vectors during penetration tests or cybersecurity threat hunting.

Some examples of effective Google Dorking searches include:

• site: targetdomain.com ext:log – Find log files
• site: targetdomain.com inurl:temp – Access temporary files
• site: targetdomain.com intext:@targetdomain.com – Retrieve internal emails
• site: targetdomain.com filetype:pdf “Confidential” – Look for confidential docs

The list of specially formatted queries is endless. Skilled penetration testers assemble lists of Google Dork searches focused on unearthing sensitive information tailored to the target organization and industries.

Although Google does apply limits, even free users can run a fair amount of queries by mixing up search inputs. When hammering searches, proxies also help bypass any temporary blocks by Google. And for important engagements, the technique proves plenty effective before hitting any friction.

Key Strengths: Leverages Google’s unmatched access to indexable web content, flexible search capabilities

Limitations: Limits imposed on number of searches, reliance on exact formatting

6. Maltego

Maltego serves as an intelligence gathering and data mining tool that lets users gather information across open and restricted sources to map out robust threat landscapes focused on targets. Using link analysis and data correlation techniques, Maltego can take small snippets like an email address or IP block to discover relationships between hacking groups, compromised accounts, data breaches, exposed networks, beneficial ownership ties, and more.

As a graphical tool, Maltego excels at enabling defenders to speed up investigations through automation. For penetration testers and hackers alike, Maltego provides an excellent support tool to expand reconnaissance efforts and pivot between findings through link analysis and relationships.

Sample use cases include:

• Gathering information on target company executives to inform social engineering
• Pivoting attacks across wider business relationships and partnerships
• Identifying beneficial owners and decisionmakers behind target domains
• Exploring data breach implications across wider user bases

Pricing starts at $14,000 per year for commercial entities, putting Maltego’s capabilities firmly in the enterprise bracket. However, a free community edition is offered enabling getting hands-on experience with more limited datasets.

Key Strengths: Graph-based analysis, automation workflows and reporting

Limitations: Steep licensing costs, advanced workflows have a learning curve

7. TheHarvester

TheHarvester lives up to its name enabling the automated gathering of public-facing organizational assets including email addresses, hostnames, IPs, and subdomain information from a diverse set of openly accessible sources. Offering exceptional scale in an open-source package, TheHarvester simplifies the process of assembling lists penetration testers need to strategize attack plans and social engineers require to launch precisely targeted phishing campaigns. TheHarvester gathers data from sources spanning hacked database leaks, DNS servers, search engine results, PGP key servers, and SHODAN queries.

Running TheHarvester follows a simple methodology:

$ python theharvester.py -d targetdomain.com -b google

This single command will harvest available data from Google sources on the specified target. For users wanting to extract data from all available sources, simply omit the -b switch specifying any particular data site.

Overall, TheHarvester presents an easy route to mass information gathering–eliminating 10x the manual effort. For attackers without budgets to spend on enterprise-grade intelligence tools, TheHarvester enables assembling high-quality target lists fueling social engineering campaigns. Meanwhile, blue teams use TheHarvester to model what data is exposed to enemies in attempts to minimize attack surfaces.

Key Strengths: Speed of extraction, diverse public data sources, easy to operate

Limitations: Raw data requires manual analysis or cleanup

8. Recon-ng

Recon-ng offers a full-featured web reconnaissance framework powered by Python. Recon-ng structures workflows as modules enabling easily deployment of tactics honed over years by veteran hackers. Leveraging over 50 modules, penetration testing teams can gather invaluable data on organizations to pinpoint high-risk vulnerabilities ripe for exploitation.

Sample Recon-ng modules:

• dns_bruteforce – Attempts to brute force subdomains
• netcraft – Queries Netcraft database for available history/technologies used
• shodan_hostname – Passes target to SHODAN API to find associated IPs/ports/banners

Recon-ng shines in providing the flexibility to customize modules for specific data needs and launch mass automated queries helping analysts bypass manual processes. The tool works well for offensive security researchers and red teams that need to validate vulnerabilities at scale. Blue teams can also leverage Recon-ng to validate assets exposed on the public web.

The open-source and modular nature of Recon-ng has cultivated an active community constantly adding to its capabilities as well. For novice penetration testers, Recon-ng delivers an easy doorway to harnessing OSINT at a large scale.

Key Strengths: Custom workflows integrating OSINT best practices, automation features

Limitations: Steeper learning curve, intensive computation requirements during large queries

Additional OSINT Resources

The tools covered so far provide exceptional capabilities for harvesting publicly available data. However, a few other notable resources deserve mention as well:

• Public Databases – Billions of credentials and personal records exposed in breaches can be checked for links to targets using services like DeHashed and We Leak Info.
• Certification Authorities – Platforms including Censys and Spyse enable querying certificate transparency logs to map target’s web assets.
• Domain Research Tools – Domain Dossier and SecurityTrails provide history/trackers on registered websites.

Additionally, examining professional certifications, code repositories, and research publications can provide invaluable business intelligence.

Real-World OSINT Penetration Testing Use Cases

To appreciate how powerful OSINT tools truly are, let’s explore some potential real-world offensive applications.

Targeted Social Engineering

An attacker first thoroughly researches key decisionmakers at a target organization through mining social media profiles, press releases, Google searches, LinkedIn pages, and past conference talks. Details gathered are used to craft authentic-looking phishing emails customized with subjects related to personal interests or hot industry topics sure to grab attention. Links embed convincing landing pages gathering credentials or dropping malware tailored to the target‘s environment. Such personalized social engineering messages see dramatically higher success rates compared to traditional spray and pray techniques.

Strategic Vulnerability Discovery

Before attacking infrastructure, hackers can leverage Shodan to pinpoint forgotten servers and devices readable without authentication. Searching for vulnerable models or technology combinations refine targets further. Passive DNS analysis and timestamp tracking of infrastructure changes help spot recently added hardware possibly overlooked during patching windows as well. Rather than blindly scanning entire ranges, OSINT enables precisely fingerprinting and validating high probability targets first.

Post-Exploitation Lateral Movement

As attackers breach initial points of entry, OSINT aids expanding footholds rather than triggering alerts moving directly across networks. Internal documentation or call recording transcripts referencing server names and software in use provide key pivot points. Compromised Slack/Teams/Email conversations discuss yet more assets and credentials prime for lateral movement. Maltego charts then visualize relationships between breached users, data stores, business units, and applications guiding exploration.

These examples showcase but the tip of the iceberg of what talented penetration testers or motivated attackers can orchestrate using OSINT. However, defenders also gain immense benefit applying the same techniques for proactive cyber threat modeling.

Conclusion

This guide provides a comprehensive overview of 8 powerful OSINT tools enabling penetration testers to thoroughly profile targets, accelerate security assessments, and expand access intelligently. From gathering backgrounds on executives to pinpointing vulnerable systems, each showcases unique strengths in simplifying large-scale data gathering. While pricing and complexity levels vary across tools, this cross-section captures OSINT capabilities accessible to everyone from individual hackers to enterprise red teams. Beyond the tools profiled, examining additional resources such as exposed databases, certificate logs, code repositories, and research publications paint further valuable insights into target environments.

As more business functions move online and personal usage grows, immense spans of data will provide ammunition powering future cyber campaigns. Defenders face uphill battles to lock down assets, while individual user mistakes provide attackers an endless supply of launch points. Ultimately organizations must apply OSINT internally to thoroughly model risk landscapes, identify overexposed resources before enemies, monitor external chatter on emerging threats, and validate that security controls operate as intended. OSINT is no longer an isolated domain merely supporting penetration testing, but now a fundamental capability underpinning resilient cyber strategies.