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Cyber Security Tutorial

Scanning Networks

Introduction to Network Scanning

Network scanning is the process of identifying the active devices on your network for vulnerabilities. It inspects and recognizes the connected devices and external and internal components are interconnected by displaying features in the network protocol. The feature takes the liable signals to give a response based on the condition of your network security.

Benefits Ethical Hacking and Penetration Testing

1.   Vulnerability Assessment

One of the foremost advantages of network scanning is its ability to uncover vulnerabilities lurking within your network infrastructure. It diligently identifies open ports, outdated software, and misconfigurations that could serve as entry points for cyberattacks. This proactive identification arms your organization with critical knowledge, enabling you to patch and secure systems promptly, thus substantially reducing the risk of data breaches.

2.   Enhanced Security

Network scanning acts as an ever-vigilant early warning system. It empowers you to detect malicious activities or unauthorized devices traversing your network promptly. With real-time monitoring, it is your sentinel, allowing you to respond swiftly to potential threats. This not only safeguards your invaluable data and digital resources but also strengthens the trust of your clients and stakeholders.

3.   Compliance and Regulation Adherence

For many industries, compliance with regulatory standards is mandatory. Network scanning assists in meeting these requirements by conducting periodic scans and

generating detailed reports. This not only helps maintain compliance but also demonstrates your commitment to data security.

4.   Optimal Network Performance

Efficiency matters in today’s digital world. Network scanning helps optimize your network by identifying bottlenecks, bandwidth hogs, and latency issues. By addressing these concerns, you can ensure seamless operations and a positive user experience.

5.   Asset Management

Effective asset management is synonymous with resource optimization. Network scanning offers a comprehensive inventory of devices and software residing within your network’s confines. Armed with this inventory, you can make informed decisions regarding resource allocation, track hardware and software lifecycles effectively, and ultimately reduce unnecessary costs.

6.   Cost Savings

Proactivity in cybersecurity translates directly into cost savings. Network scanning allows you to:

  • Significantly reduce expenses associated with data breaches, downtime, and post-incident recovery efforts.
  • Optimize resource allocation, eliminating waste and reducing operational
  • Safeguard your organization’s financial health by preventing potential financial losses.

7.   Continuous Monitoring

Cyber threats evolve continuously, making proactive security measures essential. Network scanning offers continuous monitoring, ensuring that your network remains secure even as new vulnerabilities emerge.

8.   Risk Mitigation

Informed decision-making is crucial in managing cybersecurity risks. Network scanning provides the data needed to prioritize and mitigate risks effectively, allowing you to focus resources on the most critical areas.

Types of Network Scanning

Port Scanning

Vulnerability Scanning

Network Mapping

Port Scanning

Port scanning is a method of determining which ports on a network are open and could be receiving or sending data. It is also a process for sending packets to specific ports on a host and analyzing responses to identify vulnerabilities.

Common Port Scanning Techniques

➢ TCP Scan

TCP (Transmission Control Protocol) scans are designed to identify open, closed, or filtered ports on a target system by interacting with the TCP three-way handshake process.

It establishes a full connection with the target system by completing the SYN (synchronize), SYN-ACK (synchronize-acknowledge), and ACK (acknowledge) sequence.

➢ UDP Scan

UDP (User Datagram Protocol) scans check for open ports that respond to UDP packets, focusing on connectionless services like DNS, SNMP, or TFTP.

  1. A UDP packet is sent to a
  2. If the port is open, it responds with a service-specific reply or no response at all.
  3. If closed, it sends back an ICMP “port unreachable”

➢ SYN Scan (Half-Open Scan)

A SYN scan is a stealthy technique that only partially completes the TCP handshake to identify open ports without fully establishing a connection.

A SYN packet is sent to the target port. Responses:

  • SYN-ACK: Port is
  • RST (reset): Port is
  • No response or ICMP error: The port may be filtered or

The scanning tool sends a RST packet instead of completing the handshake to minimize detection.

➢ ACK Scan

An ACK scan is used to map firewall rules and determine whether ports are filtered or unfiltered, rather than checking their open or closed status.

An ACK packet is sent to the target port. Responses:

  • RST: Indicates the port is unfiltered (firewall allows the traffic).
  • No response or ICMP error: Port is filtered (firewall is blocking).

Vulnerability Scanning

Vulnerability scanning is a crucial process within any comprehensive cybersecurity program. It involves the automated detection of security weaknesses in software, systems, and networks, allowing organizations to identify and address potential threats before attackers can exploit them. Vulnerability scanning is vital in managing cyber risks, helping businesses safeguard sensitive data and maintaining regulatory compliance.

How vulnerability scanning works ?

Vulnerability scanning follows a structured approach to identify and manage potential weaknesses in an organization’s IT infrastructure. Here’s how it works:

1.   Identification and Inventory

The process begins with identifying and cataloging all systems, devices, and software within the organization. This comprehensive inventory helps create a detailed overview of the IT environment, serving as a critical foundation for the subsequent scanning and analysis.

2.   Detection and Analysis

With the inventory in place, automated scanning tools detect vulnerabilities. These tools compare system configurations, software versions, and network settings against a database of known vulnerabilities. The detected vulnerabilities are then analyzed and categorized based on their severity, potential for exploitation, and impact on the business.

3.   Remediation and Continuous Monitoring

Once vulnerabilities are identified, the next step is remediation, which involves applying fixes, updates, or changes to address the issues. After remediation, rescanning is performed to verify that the vulnerabilities have been effectively resolved. Continuous monitoring is then implemented to detect and address new vulnerabilities, ensuring ongoing protection.

Network Mapping

Network mapping is the process of discovering all entities linked to a network. Network mapping solutions visualize physical and virtual networks and provide in-depth visibility

into enterprise IT infrastructure. Organizations use network mapping to simplify network monitoring and swiftly pinpoint network faults with network mapping tools.

How Does Network Mapping Work?

Network mapping solutions gather and interpret data using easy-to-read visualizations that accurately reflect the status of the enterprise network and all linked devices. Alerts are generated to notify IT personnel of network problems such as excess traffic or abnormal behavior. Simply checking the map allows IT teams to spot devices exhibiting problems and gain additional context-driven data to help figure out the cause of the issue quickly. The metrics gauged by network mapping tools include latency, bandwidth, and throughput.

Network mapping solutions leverage an active probing methodology to collect network data. This method relies on probe packets sent from node to node to collect IP addresses and other technical information. In larger networks, such probing activity may simply gather general, non-confidential node data to provide a less-detailed overview of network operations. However, more advanced network mapping software allows tech teams to gain in-depth insights into the workings of any device on the network by clicking on the map. Such solutions are more resource-intensive in terms of processing power and storage.

Network mapping solutions generally use simple network management protocol (SNMP) to discover and map network objects automatically. SNMP works by exposing technical data as variables on the managed systems. These variables are organized in a management information base (MIB) that describes the configuration and status of the

system. Managing applications can remotely query and sometimes even manipulate these variables.

Network mapping solutions leverage SNMP to determine the type of device and collect associated information from all entities on a network. This data is then automatically used to create an object in the map diagram.

At the most superficial level, network mapping works because every network is a massive cache of data simply waiting to be tapped. Network mapping tools use MIB via SNMP to collect details that are part of open standards and information specific to the device and vendor. This gives IT teams access to advanced device information such as the number of active ports, the device’s power draw, and even the temperature value.

Network mapping solutions allow enterprises to easily track what’s on the network, automatically gather information about all the devices, and monitor how the entities are linked together.

Scanning Techniques

What is Active Scanning?

Active scanning is a scanning method whereby you scan individual endpoints in an IT network for the purpose of retrieving more detailed information. With active scanning, you send packets or queries directly to specific assets rather than passively collecting that data by “catching” it in transit on the network’s traffic. Simply put, active scanning is an immediate deep scan, done on selected targets, to get very detailed information. These targets can be single devices or groups of devices.

What is Passive Scanning?

Passive scanning is a scanning method that continuously scans an entire network for the purpose of monitoring all connected devices at the same time. In doing so it only gathers basic asset information that it intercepts in the network traffic. The fact that it monitors continuously makes passive scanning also very useful for cybersecurity reasons, as it can, for example, instantly detect rogue devices.