Determine Target OS Through Passive Footprinting

Operating system information is crucial for every ethical hacker. Ethical hackers can acquire details of the operating system running on the target machine by performing various passive footprinting techniques and obtain other information such as the city, country, latitude/longitude, hostname, operating system, and IP address of the target organization.

Here, we will gather target OS information through passive footprinting using the Censys web service.

Launch any browser, in this lab we are using Mozilla Firefox. In the address bar of the browser place your mouse cursor and type https:// search.censys.io/?q= and press Enter.

In the search field, type the target website (here, www.hackthebox.eu) and press Enter. From the results, click any Hosts IP address which you want to gather the OS details.

The selected host page appears, as shown in the screenshot. Under the Basic Information section, you can observe that the OS is Ubuntu. Apart from this, you can also observe other details such as protocols running, software, host keys, etc. This information can help attackers in identifying potential vulnerabilities and finding effective exploits to perform various attacks on the target organization.

This concludes the demonstration of gathering OS information through passive footprinting using the Censys web service.

You can also use webservices such as Netcraft (https://www.netcraft.com), Shodan (https://www.shodan.io), etc. to gather OS information of target organization through passive footprinting.