The Hacker’s Search Engine: Exploring the Internet’s Blind Spots with Shodan
Key Points
Unlike Google, Bing and Yahoo, which index websites, Shodan indexes devices connected to the internet. These are publicly accessible but hidden by traditional search engines.
Shodan is used by researchers, investigators, both white and black hat hackers, governments, and criminals for a variety of cases.
Shodan is a tool to map of the internet’s vulnerabilities - it can be used for both good and evil.
Shodan is often described as the most powerful search engine you have never heard of.
Unlike Google, Bing and Yahoo, which index websites, Shodan indexes devices connected to the internet. These are publicly accessible but hidden by traditional search engines. Shodan is the tool that reveals them.
Security researchers call it a map of the internet’s vulnerabilities. It shows what is open, what is outdated and what is misconfigured. Over the years, Shodan has exposed thousands of unsafe systems. It records the fingerprints of servers, webcams, IoT devices, industrial machines and even sensitive infrastructure such as power plant interfaces or water supply controls. Much of this is visible because people forget to hide it.
These findings have raised urgent questions about digital hygiene and the ease with which hackers can find weak points. As such, Shodan has been at the centre of several high-profile investigations and stories – involving exposed baby monitors, unsecured hotel heating systems, online industrial dashboards, and even a malware-infected computer at the Indian Space Research Organisation (ISRO).
Shodan exposes the scale of the problem. It helps them understand how much of the modern world is connected through weak configurations. It is a necessary source of information for cybersecurity researchers, while hackers use the same visibility for reconnaissance.
What is Shodan?
“Search Engine for the Internet of Everything,” reads the search engine's homepage.
Shodan is an indexer of internet-connected devices. It continuously probes IP addresses around the world. When it finds a device, it records the information that the device sends back. This normally includes open ports, the software running on those ports, service banners and metadata about versions and configuration. It then organises this information so that users can search for devices by location, organisation, technology, hardware, or access.
Shodan was created by John Matherly in 2003 as a pet project. He mapped all internet connected devices by randomly generating IP addresses and indexing any information reverted back. He named his project after the main villain in the cyber-punk video game System Shock – SHODEN (Sentient Hyper-Optimized Data Access Network).
In 2009, Matherly released his program publicly. He expected it to be used by large companies to map vulnerabilities in their infrastructure or for market research. But the tool was quickly picked up by researchers and hackers too.
Traditional search engines rely on websites to invite crawlers. Shodan does not wait for permission, it scans the internet by itself by accessing random IP addresses. It observes systems exactly as they appear when they are exposed to the outside world.
The data it collects is technical and minimal – never anything illegal. For example, Shodan reports that a server is running a specific OS, the type of webcam, industrial controller or router listed, whether a database is password-protected or not, or whether a device uses outdated security protocols.
Shodan is like a catalogue of the world’s digital doors, also called ports. Some doors are locked properly, others are half open, while some are completely unlatched. It is not a tool that breaks into systems, it only shows what the system itself reveals. The threat comes from the fact that so many systems reveal far more than they should.
What Can Shodan Do?
Shodan allows users to look up any IP address and filter searches by device type, service, location and network. It can be used in a variety of ways by different actors:
To discover exposed devices by searching for terms like “default password”, “webcam” or a specific port number.
To assess security posture by locating devices with known vulnerabilities, obsolete firmware or weak configurations.
To map internet attack surfaces – businesses and researchers can analyse their own network exposure and track devices across locations or geo-regions.
To gather intelligence by observing trends, scanning for misconfigured devices, monitoring industrial infrastructure and understanding exposure of assets.
Shodan is used by several groups: researchers use it to find weaknesses before attackers do, white-hate hackers use it to study the spread of unsafe technologies, governments use it to understand whether their online infrastructure is publicly visible, and criminal groups use it for reconnaissance.
The power of Shodan comes from its simplicity – users have limited access without an account, with paid tiers offering additional features. No technical skill is required to look up devices. This has sparked debates about whether such visibility should be openly available, but Shodan’s creators argue that hiding the problem does not fix it, operators should secure their systems instead.
What Has Shodan Been Used For?
Over the years, hackers and netizens have taken it up as a challenge to find the most improbable devices on the engine – from smart fridges to city-wide traffic light networks, crematorium settings to nuclear plant controls.
Common uses include discovering industrial control panels, unsecured webcams, devices with outdated firmware, unprotected databases, building controls, and public infrastructure.
In 2013, Forbes revealed how, one night, a man heard a strange voice coming from his 2-year-old daughter’s room. When he investigated, he found out that his baby monitor had been hacked and the actor had gained control of both the mic and the camera. A search on Shodan for the baby monitor model in question revealed 40,000 other potential targets.
A 2024 article by Cybernews detailed how hacktivists have gathered information on industrial controls and CCTVs to aid actors in the Palestine-Israel and Ukraine-Russia conflicts. One group in particular took down Russia’s entire train system in 2022 in order to limit military supplies being transported to the frontline of the war. Information about the railway infrastructure was publicly available on Shodan.
In 2018, The New Indian Express made another case public – one a little closer to home. An independent researcher, in December 2017, identified signs of malware inside an ISRO computer. The malware was a Remote Access Trojan (RAT), which would have allowed a malicious actor complete control of ISRO’s systems. The discovery was made using Shodan. “If Shodan can be used for searching hacked sites, I thought, why not search for infected servers?” the researcher had said, “I filtered it down to region and ISRO showed up in the scan results.”
These incidents underline the same point. Devices are often put online without proper configuration. Shodan simply proves how visible they are.
How to Protect Yourself from Shodan
Protecting against Shodan exposure starts with basic digital housekeeping.
Ensure devices are not directly exposed to the internet
Use strong passwords and updated firmware
Disable unused ports and services
Place sensitive devices behind firewalls
Conduct regular internal audits
Restrict remote access
Avoid default credentials
Use network segmentation to hide critical systems
Further, Shodan itself can be used to evaluate vulnerabilities within one’s network. Security teams increasingly use Shodan as an internal auditing tool. They search for their own systems to see what outsiders can view and if a server appears unexpectedly, it becomes a sign that something is misconfigured. You can do the same.
In the end, Shodan is simply a tool.
“I don’t consider my search engine scary,” Matherly told Forbes in 2013, “It’s scary that there are power plants connected to the internet.”
“Everything is going on the Internet whether you want it or not,” he continued. Malicious actors already have the means to utilise the data Shodan makes public – it just levels the playing field. [Rh]
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