Google crawls content—the words people write, the pages they publish, the information they share. Shodan crawls infrastructure—the machines that actually run the world. While traditional search engines index HTML and text to help you find blog posts and Wikipedia articles, Shodan indexes the service banners of every device connected to the internet. If a device has an IP address and a port open to the public, Shodan has likely knocked on its door and written down exactly what it said.
The sensationalist media loves to call Shodan the “hacker’s playground” for finding open webcams and exposed databases. Unsecured devices are absolutely visible on Shodan—that part is true. But the reality is far more professional than the headlines suggest. In 2026, Shodan has become the gold standard for Attack Surface Management (ASM). Security teams at Fortune 500 companies use it every day to map their digital footprints, identify exposed assets before attackers find them, and close security gaps before they become breach headlines. This Shodan search engine guide moves beyond the scary stories to teach you a professional workflow: Search, Verify, and Monitor.
Core Concepts: How Shodan Actually Works
Understanding Shodan requires grasping three technical pillars. Shodan does not “hack” systems—it simply listens to what those systems are already broadcasting to anyone who asks. Think of it as a census of the internet, documenting what devices exist and what they’re willing to share about themselves.
Banner Grabbing: The Digital Handshake
Technical Definition: Banner grabbing is the process of connecting to a networked device and recording the metadata—known as a “banner”—that the device sends back in response. This banner contains identifying information about the service running on that port, including software names, version numbers, and configuration details. Shodan’s crawlers perform this process billions of times across the entire IPv4 address space.
The Analogy: Think about the difference between Google and Shodan like this: Google is a neighbor who reads the newspaper left on your porch. They see what you’ve chosen to make publicly visible. Shodan is more like a building inspector who knocks on every door in the neighborhood and waits for an answer. The inspector doesn’t force entry—that would be illegal. But when you answer the door and say “Hi, I’m running Apache Server version 2.4.41 on Ubuntu 20.04,” the inspector writes that down verbatim.
Under the Hood:
| Component | Function | Technical Detail |
|---|---|---|
| Crawler Network | Distributed scanning infrastructure | Global nodes send connection requests to every IP address across common ports |
| Connection Request | Initial handshake attempt | TCP SYN packet sent to target IP:port combination |
| Banner Capture | Response recording | Raw text response from service stored with timestamp and metadata |
| Data Fields | Extracted information | Software name, version, OS, certificates, headers, CVE associations |
| Index Update | Database storage | Banner data indexed for search with geolocation enrichment |
The banner itself can reveal an extraordinary amount of information. A typical HTTP banner might expose the web server software, PHP version, operating system, and even custom headers that reveal internal hostnames or application frameworks. An SSH banner reveals the SSH protocol version and often the underlying operating system. Database banners from MySQL or MongoDB might expose version numbers with known vulnerabilities. This information is freely given by the devices themselves—Shodan simply catalogs it at scale.
Ports and Services: The Entry Points
Technical Definition: Ports are virtual endpoints where network traffic enters and exits a device. Each port number (0-65535) can host a different service. Common services run on well-known ports: HTTP on port 80, HTTPS on 443, SSH on 22, RDP on 3389. When Shodan scans an IP address, it checks multiple ports to identify which services are actively listening and accepting connections.
The Analogy: If an IP address is a house, ports are the windows and doors. Shodan walks around the neighborhood checking which windows are open, which doors are unlocked, and what’s visible through the glass. It doesn’t climb in through the window—but it does note that the kitchen window is open and there’s a laptop visible on the counter.
Under the Hood:
| Port | Service | What Shodan Captures |
|---|---|---|
| 22 | SSH | Protocol version, key fingerprint, authentication methods |
| 80 | HTTP | Web server software, response headers, page titles |
| 443 | HTTPS | SSL/TLS certificate details, issuer, expiration, SANs |
| 3389 | RDP | Windows version indicators, NLA status, certificate info |
| 3306 | MySQL | Database version, authentication capabilities |
| 27017 | MongoDB | Version, authentication status, database names if exposed |
| 5900 | VNC | Authentication requirements, desktop sharing status |
| 1883 | MQTT | IoT messaging broker version, authentication status |
When a port is “listening,” it signals that an active service is ready to accept connections from the internet. This is the digital equivalent of leaving your front door unlocked and propped open. Some services are meant to be public—web servers serving your company website, for example. Others—like database management ports or remote desktop services—should almost never be exposed to the public internet without additional protection.
The Snapshot Reality: Point-in-Time Data
Technical Definition: Shodan is a historical index, not a real-time live feed. The data you see represents the state of a device at the moment Shodan’s crawler last visited. The timestamp field shows when that scan occurred. Depending on the IP address’s popularity and the port in question, this data could be hours, days, or weeks old.
The Analogy: Shodan works exactly like Google Street View. You see what the house looked like the day the camera car drove by. If you painted your front door yesterday, the old color shows in the photos until Google’s car returns. If a system administrator patched a vulnerability last week, Shodan might still show the old, vulnerable version until the next scan cycle refreshes that record.
Under the Hood:
| Factor | Impact on Data Freshness | Practical Consideration |
|---|---|---|
| IP Popularity | High-traffic IPs scanned more frequently | Major hosting providers updated more often |
| Port Priority | Common ports (80, 443, 22) scanned first | Obscure ports may have stale data |
| Scan Credits | On-demand scans bypass the cycle | Fresh scans available with paid credits |
| Geographic Location | Some regions scanned less frequently | Remote networks may have older data |
| Device Responsiveness | Slow devices may timeout | Incomplete banners for overloaded systems |
This snapshot reality has critical implications for security work. You cannot assume that a vulnerability shown in Shodan still exists. You also cannot assume that a clean Shodan record means a device is secure—it might have become vulnerable after the last scan. Verification is always required. Cross-reference Shodan data with real-time reconnaissance, and never treat Shodan results as definitive proof of current state.
The Toolbox: Mastering the Language of Filters
Mastering the Shodan search engine guide means learning its query syntax. Unlike Google, Shodan uses structured filters in a filter:value format. Logic is additive by default—each additional filter narrows your results further with an implicit AND operator.
The Essential Filter Arsenal
These five filters form the foundation of professional Shodan work. Combine them strategically to isolate exactly the devices you need to find.
| Filter | Purpose | Example Query | What It Finds |
|---|---|---|---|
| port: | Target specific services | port:22 | All devices with SSH listening |
| country: | Geographic focus | country:DE | Devices located in Germany |
| org: | Organization targeting | org:"Amazon" | Assets within Amazon’s IP space |
| product: | Software identification | product:"nginx" | Servers running Nginx |
| vuln: | Vulnerability search | vuln:CVE-2021-44228 | Devices vulnerable to Log4Shell |
The vuln: filter deserves special attention. It identifies devices with specific CVE (Common Vulnerabilities and Exposures) numbers. This is extraordinarily powerful for both offense and defense—attackers use it to find targets, while defenders use it to find their own vulnerable assets before attackers do. Note: The vuln filter requires at least a Small Business plan subscription. Free and basic Membership accounts cannot access vulnerability data directly.
Advanced Filter Combinations
Real power comes from chaining filters together. Each additional filter acts as a precision instrument, cutting away irrelevant results until only your targets remain.
| Use Case | Query | Result |
|---|---|---|
| US Nginx Servers | product:"nginx" port:80 country:US | US-based web servers running Nginx |
| Exposed RDP in Finance | port:3389 org:"JPMorgan" | Remote Desktop within JPMorgan’s IP ranges |
| Industrial Controllers | port:502 product:"Modbus" | Modbus-enabled industrial control systems |
| Unpatched Apache | product:"Apache" version:"2.4.49" | Apache servers on a vulnerable version |
| Webcams in Hospitals | org:"Hospital" product:"webcam" | IoT cameras in healthcare networks |
| MongoDB No Auth | product:"MongoDB" -authentication | MongoDB instances without authentication |
Pro-Tip: Use quotes around multi-word values. org:Amazon and org:"Amazon" return different results—the former might include partial matches, while the latter ensures exact organization matching. When using the CLI with quoted queries, wrap them in an additional set of quotes: 'city:"San Diego"'.
Boolean Logic and Exclusions
Shodan supports negative filtering with the minus operator. If you want to find all SSH servers except those in China, use: port:22 -country:CN. This exclusion logic helps clean up results when you know certain segments aren’t relevant to your analysis.
You can also search banner content directly without a filter prefix. Searching "default password" finds any device whose banner contains that exact phrase—often revealing devices where administrators never changed factory credentials.
Industrial Control Systems: Critical Infrastructure Exposure
Shodan’s ability to discover Industrial Control Systems (ICS) and SCADA devices makes it particularly valuable—and concerning—for critical infrastructure security. As of early 2024, Shodan identified nearly 110,000 ICS devices exposed to the public internet, including over 6,500 publicly accessible programmable logic controllers (PLCs).
ICS Protocol Reference
Technical Definition: Industrial protocols govern communication between control systems, sensors, and actuators in manufacturing, utilities, and critical infrastructure. Unlike IT protocols designed with security in mind, many ICS protocols were developed decades ago for isolated networks and lack authentication entirely.
The Analogy: Imagine a power plant’s control room. IT protocols are like the locked front door with a keypad. ICS protocols are like the maintenance hatch in the back—originally designed for workers who were already inside the building, with no expectation that strangers would find it.
Under the Hood:
| Protocol | Port | Industry | Shodan Query | Security Status |
|---|---|---|---|---|
| Modbus | 502 | Manufacturing, HVAC | port:502 | No native authentication |
| DNP3 | 20000 | Electrical utilities | port:20000 | Optional authentication |
| BACnet | 47808 | Building automation | port:47808 | Limited security features |
| Siemens S7 | 102 | Industrial automation | port:102 | Proprietary, weak security |
| EtherNet/IP | 44818 | Industrial automation | port:44818 | CIP security optional |
| IEC 60870-5-104 | 2404 | Power systems | port:2404 | No encryption by default |
Real-World Threat Actor Usage
Nation-state actors actively use Shodan for reconnaissance. According to joint CISA/NSA/FBI advisories, the Chinese APT group Volt Typhoon uses Shodan alongside FOFA and Censys to identify exposed infrastructure before attacking U.S. critical systems. In late 2023, the Iranian hacktivist group Cyber Av3ngers attacked Unitronics PLCs globally—including a water utility near Pittsburgh—after discovering targets through internet-scanning platforms. Following these attacks, exposed Unitronics devices dropped from over 1,800 to 937.
Pro-Tip: If you manage industrial systems, run port:502 org:"Your Organization" monthly. Finding your own PLCs before threat actors do could prevent the next headline-making incident.
Step-by-Step Implementation: The Professional Workflow
Level 1: Web Interface Discovery
The web interface at shodan.io serves as your reconnaissance dashboard. Start here for initial discovery before moving to more advanced methods.
The Explore Tab showcases trending vulnerabilities and common misconfigurations updated in near-real-time. This tab reveals what the security community is currently hunting—whether it’s a new Log4j variant, exposed Kubernetes dashboards, or industrial controllers with default passwords.
Facet Analysis appears in the sidebar of search results and provides aggregate statistics about your query. You can see the top countries, organizations, ISPs, ports, and products in your result set. This bird’s-eye view helps you understand the landscape before drilling into specific hosts.
| Web Interface Feature | Purpose | When to Use |
|---|---|---|
| Explore Tab | Trending vulnerabilities | Daily threat landscape check |
| Facet Analysis | Statistical breakdown | Understanding result distribution |
| Maps View | Geographic visualization | Regional exposure assessment |
| Images Search | Visual device identification | Finding webcams and screenshots |
| Reports | Saved search summaries | Tracking exposure over time |
Level 2: Command Line Power
The CLI transforms Shodan from a search tool into an automation platform. Install it with pip install shodan and initialize with your API key using shodan init YOUR_API_KEY.
| CLI Command | Function | Example Usage |
|---|---|---|
shodan host [IP] | Retrieve all data for a specific IP | shodan host 8.8.8.8 |
shodan myip | Show your public-facing IP and services | Quick self-audit in 2 seconds |
shodan search [query] | Execute filter-based search | shodan search --fields ip_str,port,org product:nginx |
shodan download [file] [query] | Bulk data export to JSON | shodan download --limit 500 mongodb-data product:mongodb |
shodan parse [file] | Extract fields from downloaded data | shodan parse --fields ip_str,port --separator , data.json.gz |
shodan convert [file] [format] | Convert to CSV, KML, or other formats | shodan convert data.json.gz csv |
shodan scan submit [IP] | Request fresh scan | Real-time verification of current state |
shodan stats [query] | Aggregate statistics | Understanding exposure at scale |
The shodan host command deserves emphasis. When you run shodan host 8.8.8.8, Shodan returns everything it knows about that IP address—open ports, banners, associated vulnerabilities, SSL certificates, and historical data—without ever connecting to the target directly. This is passive reconnaissance: you’re querying Shodan’s database, not the target itself. No packets reach the destination, no intrusion detection systems trigger, no logs record your interest.
Pro-Tip: Run shodan myip from any network you manage. It shows exactly what Shodan sees when it scans your public IP—a two-second audit that might reveal services you didn’t know were exposed.
Level 3: Continuous Monitoring with Shodan Monitor
Searching Shodan answers the question “What’s exposed right now?” Shodan Monitor answers the more important question: “What changed since yesterday?”
Configure Monitor to watch your IP ranges or domains. When a new port opens, a service changes, or a new vulnerability is detected, you receive an alert via email, Slack, or webhook. This shifts your strategy from reactive searching to proactive defense.
| Monitor Capability | Detection | Response Action |
|---|---|---|
| New Port Opens | Unauthorized service deployment | Investigate shadow IT or compromise |
| Service Changes | Software update or reconfiguration | Verify intentional change |
| New CVE Detected | Vulnerability affects your asset | Prioritize patching |
| SSL Certificate Expiry | Certificate approaching expiration | Renew before outage |
| Banner Change | Service configuration modified | Validate expected behavior |
Monitor is the difference between hoping you’ll notice an exposure and knowing the moment it appears. For organizations with significant internet-facing infrastructure, continuous monitoring isn’t optional—it’s essential hygiene.
Common Mistakes and Critical Misconfigurations
Mistake 1: Crossing the Legal Line
Shodan itself is perfectly legal. It indexes public data—information that devices freely broadcast to anyone who connects. Using Shodan to find that a server is running Apache 2.4.49 is no different from looking at a building’s exterior. The line is crossed when you act on that information inappropriately.
If you find a device with default credentials visible in its banner and you use those credentials to log in, you’ve committed unauthorized access—a federal crime under laws like the Computer Fraud and Abuse Act (CFAA) in the United States. Look, verify, report—never interact. Security researchers document findings and report them through responsible disclosure channels. They don’t log into systems they don’t own.
Mistake 2: Falling for Honeypots
A honeypot is a deliberately vulnerable-looking system designed to attract and study attackers. Sophisticated honeypots mimic real services—an “exposed” MySQL database, an “unpatched” WordPress installation, a “default password” router. They look too perfectly broken.
| Honeypot Indicator | What to Watch For |
|---|---|
| Perfect Vulnerability Stack | Multiple high-profile CVEs on one system |
| Unusual Ports | Standard services on non-standard ports |
| Generic Banners | Suspiciously default configurations |
| No Other Traffic | Isolated system with no real purpose |
| Too Easy Access | Credentials that work immediately |
If you’re conducting authorized penetration testing and a target seems too easy, consider that you might be in a trap. Honeypot operators log everything—your IP, your techniques, your tools. Proceed with caution.
Mistake 3: The Free Tier Fallacy
Shodan’s free tier limits you to the first two pages of search results. For legitimate security professionals, this restriction cripples effective work. You can’t see the full scope of an organization’s exposure, you can’t download bulk data, and you can’t access vulnerability information.
The Membership (typically $49 one-time, occasionally discounted) removes the most painful constraints. It unlocks API access, full search results, and the ability to query without artificial caps. Students with .edu email addresses receive free upgrades. If you’re serious about attack surface management or penetration testing, the membership pays for itself immediately.
Understanding the Credit Economy
Shodan operates on a credit-based system that separates one-time purchase from ongoing usage. Understanding this economy helps you budget appropriately for professional work.
| Credit Type | Purpose | How They’re Used |
|---|---|---|
| Query Credits | Bulk data downloads | Exporting large datasets for offline analysis |
| Scan Credits | On-demand fresh scans | Bypassing cache for real-time verification |
| API Credits | Programmatic access | Integration with security tools and scripts |
The Membership is the foundation. This one-time, lifetime payment unlocks full search access, basic API capabilities, and monitoring for a limited number of IPs—no subscription fees, no recurring charges.
For professional API plans, Shodan offers tiered subscriptions: Freelancer ($69/month), Small Business ($299/month), and Corporate ($899/month). The vuln filter requires at least Small Business, and the tag filter for ICS discovery requires Corporate.
Query credits get consumed when you download datasets. Scan credits let you request a fresh scan of a specific IP, bypassing Shodan’s normal crawl cycle for current data immediately.
Problem-Solving Framework
| Problem | Root Cause | Solution |
|---|---|---|
| “Vulnerability searches return nothing” | Free account or Membership limitation | Upgrade to Small Business plan; alternatively, search banner text for version strings (e.g., "Apache 2.4.49") instead of using vuln: filter |
| “Worried about using my real IP” | OPSEC concern | Run CLI from a Virtual Private Server (VPS) or trusted commercial VPN; Shodan API calls don’t hit targets directly |
| “Results are overwhelming” | Missing specificity | Stack additional filters: add city:, org:, or os: to narrow scope systematically |
| “Data seems outdated” | Normal scan cycle delay | Use scan credits to request fresh scan of specific IPs |
| “Can’t find my own assets” | Unknown IP ranges | Start with org: filter using your organization name; verify IP ranges with ARIN/RIPE registries |
| “Too many false positives” | Banner misinterpretation | Verify findings manually; cross-reference with targeted Nmap scans |
| “Need data in spreadsheet format” | JSON output default | Use shodan convert data.json.gz csv to transform downloaded data |
Attack Surface Management in 2026
Shodan has evolved from a curiosity into critical infrastructure for security programs. As organizations adopt hybrid cloud architectures, IoT devices proliferate, and shadow IT expands, maintaining visibility into your internet-facing attack surface has become existential.
AI-driven risk scoring is now standard in enterprise security. Shodan’s data feeds integrate with platforms that automatically prioritize exposures. Machine learning models correlate Shodan data with threat intelligence to predict which assets attackers are most likely to target.
Real-time continuous monitoring has replaced periodic assessments. The traditional quarterly penetration test can’t keep pace with weekly infrastructure changes.
Supply chain visibility extends ASM beyond your own boundaries. Understanding what your vendors and partners expose helps assess third-party risk before it becomes your problem.
Shodan is a mirror reflecting your network to the world. If you don’t like what you see, the path forward is clear: fix your network. Secure those open ports. Patch those vulnerable versions. Configure authentication on those databases. Remove those default credentials.
Don’t guess—know. Your attack surface is visible to adversaries right now. The only question is whether you see it too.
Frequently Asked Questions (FAQ)
Is Shodan illegal to use?
No, Shodan is completely legal. It indexes publicly accessible data that devices broadcast to anyone who connects. Using Shodan is no different from using Google—you’re searching an index of information that’s already public. The illegal part begins if you access systems without authorization based on what you find.
How do I remove my device from Shodan’s index?
You cannot request deletion from Shodan’s database directly. The solution is to secure the device—close unnecessary ports, configure proper authentication, or place it behind a firewall. Once the device stops responding to Shodan’s crawlers, the record ages out and eventually disappears from search results during subsequent scan cycles.
Is the Membership worth the investment?
For anyone doing professional security work, absolutely. The one-time lifetime payment (typically $49, occasionally discounted to $5 during sales) unlocks full search capabilities, API access, and removes the crippling two-page result limit. Students and academics with .edu addresses get free membership upgrades.
Can Shodan see devices inside my private network?
No. Shodan only indexes devices with ports exposed to the public internet. If your devices are behind a properly configured NAT firewall with no port forwarding, Shodan’s crawlers cannot reach them. Shodan sees what you expose—nothing more.
How often does Shodan scan the internet?
Shodan continuously crawls the IPv4 address space, but scan frequency varies by IP and port. Popular addresses and common ports get scanned more frequently—sometimes daily. Less common ports on obscure IP ranges might not update for weeks. Use scan credits if you need guaranteed fresh data.
What’s the difference between Shodan and Censys?
Both are internet-wide scanning platforms, but they have different architectures and data coverage. Shodan has deeper historical data going back to 2017, specialized IoT device fingerprinting, and a stronger focus on industrial control systems. Censys offers more comprehensive certificate transparency data and TLS/SSL analysis. Many security teams use both for comprehensive coverage.
Can Shodan find ICS/SCADA systems?
Yes, and this is one of Shodan’s most powerful (and sensitive) capabilities. Enterprise subscribers can use the tag:ics filter to find industrial control systems. Common queries include port:502 for Modbus devices and port:47808 for BACnet building automation systems. As of 2024, Shodan indexes approximately 110,000 ICS devices globally.
Sources & Further Reading
- Shodan Official Help Center: Query syntax documentation, CLI reference, and API documentation for filter construction and programmatic access
- NIST SP 800-115: Technical Guide to Information Security Testing and Assessment—foundational methodology for security assessments
- CISA Attack Surface Management Guidance: Official U.S. government recommendations for continuous exposure monitoring
- MITRE ATT&CK Framework (T1596): Search Open Technical Databases—adversary technique documentation for reconnaissance tradecraft
- CISA/NSA/FBI Joint Advisory on Volt Typhoon: Threat actor tradecraft including use of internet scanning platforms
- Forescout Threat Briefing “Better Safe Than Sorry” (2024): Analysis of global ICS/OT exposure trends and mitigation strategies
- Shodan Blog: Case studies, new feature announcements, and Trends API documentation
