After getting the information about the target through footprinting, networking scanning is the next step in hacking. In order to discover flaws and vulnerabilities in the network, networking scanning must be done. So that hackers can plan their attacks properly, it will provide a proper structure for the network and network security.

Contents

  • Network Scanning
  • Type of Network Scanning
  • objectives of Network Scanning
  • TCP Communication Flags
  • Scanning Tools

Network Scanning

During scanning, we use reconnaissance methods to learn as much as we can know about the target. To locate hosts, ports, and services on a network, utilize network scanning. It is one of the most important stages of data collection because it helps the attacker create a profile of the target or organization. The attacker searches the target’s network for information such as specific IP addresses that can be accessed, services running on each computer, operating systems, and system architecture, among other things.

To sum up, The goal of scanning is to identify vulnerable communication channels between Networks that can be exploited. The attacker attempts to hack the target system in a variety of ways. The attacker also attempts to learn more about the target system in order to determine if it is misconfigured. This is a critical step because the attacker will use the information obtained during the sac to develop an attack strategy.

Types of Network Scanning

  • Port Scanning:- We’re talking about Virtual Ports here. These ports are not visible, but they are present in every computer and are very important for your system, such as the FTP port (File Transfer Protocol), which runs on port number 21. It is critical because if you close this port, you will be unable to share files from your computer to your network or any other system. Port scanning is important because it helps in finding of vulnerable services on that system’s ports.
  • Network Scanning:- Network scanning is a technique used to locate active hosts on a network. It allows the user to map the network and its topology, as well as locate devices that connect to that network that would be difficult to find manually scanning.
  • Vulnerability Scanning:- Vulnerability scanning is a technique for determining whether or not a system is vulnerable by identifying its vulnerabilities. There are many different kinds of vulnerability scanners out there. A vulnerability scanner consists of tools and applications that scan for a variety of files with vulnerabilities and exploits for different systems.

Objectives of Network Scanning

An attacker has more information about a target or system. More opportunities to learn about system flaws and vulnerabilities and gain unauthorized access to the system.

TCP Communication Flags

The following are the TCP communication flags

  • SynchronizeSYN“:- It transmits a new sequence number notification. For example, this flag denotes the establishment of a three-way handshake between two hosts.
  • AcknowledgmentACK“:- confirms transmission receipt and determines the next expected sequence number. When a packet is successfully received, the system sets its flag to “1,” indicating that the receiver should pay attention to it.
  • PushPSH“:- The sender has raised the push operation to the receiver when its flag is set to “1,” indicating that the remote system should notify the receiving application about the buffered data coming from the sender. To avoid buffer deadlocks, the system raises the PSH flag at the start and end of data transfers and sets it on the last segment of a file.
  • UrgentURG“:- Tells the system to process the data in packets as soon as possible When the system sets the flag to “1,” the remote system prioritizes and processes the urgent data first, halting all other data processing.
  • FinishFIN“:- It will not send any further transmissions to the remote system and will end the connection established by the SYN flag.
  • RestRST“:- When there is an error in the current connection. However, the RST flag is set, and the connection is terminated as a result of the error. Attackers use RST to scan hosts for open Ports.
Note:- SYN scanning is primarily concerned with three flags: SYN, ACK, and RST. During the enumeration process, you can use these three flags to gather illegal information from servers.

Scanning Tools

Tools used for scanning look for and locate active hosts, open ports, active services on a target network, location data, NetBios data, and TCP/IP and UDP open ports. The data gathered by these tools will assist an ethical hacker in creating a detailed profile, or “blueprint,” of the target system.

  • Nmap
  • Hping2/Hping3
  • NetscanTools Pro
  • Intruder
  • OpenVAS
  • Wireshark

1. Nmap:- www.nmap.org

Gordon Lyon created Nmap (Network Mapper), a network scanner (also known by his pseudonym Fyodor Vaskovich). Nmap is a network discovery tool that sends packets and analyses the responses to find hosts and services on a network.

above all Nmap is one of the best network scanning tools available. It is free to use and did come in both command line and graphical interface versions. Most hackers and cyber security researchers use this tool because it includes many built-in scripts for finding network vulnerabilities and loopholes. There are numerous types of scans available on this tool, so you have a variety of options for scanning the target.

2. Hping2/Hping3:- www.hping.org/download.html

hping is a TCP/IP packet assembler/analyzer with a command-line interface. The interface of Hping2/Hping3 is based on the Unix command ping, but hping can do more than just send ICMP echo requests. A traceroute mode and the ability to transmit files between secured channels are available, along with the TCP, UDP, ICMP, and RAW-IP protocols.

Hping is a tool created as a security tool for networks that can be used by anyone, including those who are not in the security profession similarly to Nmap. A subset of the things you can do with hping:

  • Firewall Testing
  • Sophisticated port scanning
  • Network testing, using various protocols, TOS, and fragmentation
  • Manual route The discovery of MTU
  • Advanced traceroute under all protocols supported
  • Remote operating system fingerprinting
  • Remote uptime estimation

TCP/IP Stacks Students learning TCP/IP can benefit from auditing hping as well. Hping is compatible with the following UNIX-like operating systems: Linux, FreeBSD, NetBSD, OpenBSD, Solaris, macOS X, and Windows.

3. Netscan Tools Pro:-  www.netscantools.com/download.html

For Network Professionals, NetScanTools Pro is an integrated collection of online information gathering and network troubleshooting software. Automatically or manually, look up IPv4 and IPv6 addresses, hostnames, domain names, email addresses, and URLs. Windows graphical user interface designed for Netscan tools Pro. The user interacts with automated tools to initiate them.

4. Intruder:- www.intruder.io

Intruder is a Vulnerability scanning that finds cyber security weaknesses in your digital infrastructure, to avoid costly data breaches.

5. OpenVAS:- www.openvas.org

OpenVAS is a comprehensive vulnerability scanner. Unauthenticated and authenticated testing, various high-level and low-level internet and industrial protocols, performance tuning for large-scale scans, and a powerful internal programming language to implement any type of vulnerability test are among its capabilities.

6. Wireshark:- www.wireshark.org

In the meantime, Wireshark is the most popular and widely used network protocol analyzer in the world. It provides a microscopic view of what’s going on in your network and is the de facto (and often de jure) standard for many commercial and non-profit enterprises, government agencies, and educational institutions. Wireshark development thrives thanks to the volunteer contributions of networking experts all over the world, and it is the continuation of a project begun in 1998 by Gerald Combs.

Conclusion

Network Scanning It is one of the most important stages of data collection because it helps the attacker create a profile of the target. The goal of scanning is to identify vulnerable communication channels between Networks that can be exploited.

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