How do hackers and security researchers scan the internet for vulnerable servers and devices

Question

Scanning the internet helps uncover misconfigured or exposed systems. What tools and techniques are commonly used to perform wide-scale vulnerability scans?

Answer 1

Hackers and security researchers employ various tools and techniques to scan the internet for vulnerable servers and devices. These methods help identify misconfigured systems, outdated software, and other security weaknesses. Below is an overview of the most commonly used tools and techniques:​

Common Tools:

1. Nmap (Network Mapper):

   • Description: An open-source tool designed for network discovery and security auditing.​

   • Features:

     • Performs host discovery, service enumeration, and operating system detection.

     • Supports various scanning techniques, including TCP, SYN, and UDP scans.

   • Use Case: Identifying live hosts and open ports on a network to detect potential vulnerabilities.​

2. Shodan:

   • Description: A search engine that indexes internet-connected devices, providing insights into exposed systems.

   • Features:

     • Aggregates data on open ports, running services, and known vulnerabilities.

     • Offers filtering capabilities to pinpoint specific device types or geographic locations.

   • Use Case: Discovering publicly accessible devices and assessing their exposure to known vulnerabilities.​

3. OpenVAS (Open Vulnerability Assessment Scanner):

   • Description: A full-featured vulnerability scanner that detects security issues in networked systems.​

   • Features:

     • Scans for a vast array of vulnerabilities across different platforms.

     • Regularly updated with the latest vulnerability tests.

   • Use Case: Conducting comprehensive vulnerability assessments to identify and mitigate security risks.​

4. Acunetix:

   • Description: A web vulnerability scanner that automates the detection of over 7,000 vulnerabilities.

   • Features:

     • Specializes in identifying issues like SQL injection and cross-site scripting (XSS).

     • Supports scanning of complex web applications and single-page applications (SPAs).

   • Use Case: Assessing web applications for common security flaws and ensuring compliance with security standards.​

Common Techniques:

1. Port Scanning:

   • Description: Involves sending packets to various ports on a target system to identify open or closed ports.​

   • Methods:

     • Ping Scans: Send ICMP requests to determine if a host is active.

     • TCP Scans: Attempt to establish TCP connections to detect listening services.

     • UDP Scans: Send UDP packets to identify open UDP ports.

   • Purpose: Identifying accessible services that might be exploited.​

2. Banner Grabbing:

   • Description: Collects information from service banners to determine the software and version running on open ports.​

   • Purpose: Identifying outdated software versions susceptible to known exploits.​

3. Web Crawling and Scraping:

   • Description: Automated tools navigate websites to discover hidden or unlinked pages and gather information.​

   • Purpose: Uncovering sensitive data exposure and assessing the structure of web applications.​

4. Fingerprinting:

   • Description: Determines the operating system and software versions of a target by analyzing responses to specific network probes.​

   • Purpose: Tailoring attacks to known vulnerabilities of detected systems.​

By utilizing these tools and techniques, hackers and security researchers can systematically identify vulnerable servers and devices, enabling proactive measures to secure systems and data.