Hacker attack--analysis of selected network attack vulnerabilities

As hacker attacks have recently been reported in the news, we all know that computer security needs to be treated seriously. Although there are many publications about software that can be used to secure your computer's environment, there are few publications that describe how the hacker attacks actually performed. If you are responsible for ensuring the security of your company's computer environment, it is important for you to understand how the hacker attacks work. In this article, Michael Pichler analyzes some of the interesting cyber attacks and explains how they work. You will see how creative hackers are and will understand how some of the features contained in your software are being used against you. This article is suitable for the network has a certain understanding, but not necessarily engaged in the network field daily work of the reader.
Basic knowledge of hackers
It is not difficult to imagine that this article can choose a wide range of attack types. I chose some of the specific attacks discussed in this article, because they do not require much knowledge about the protocols involved, they can still be effective in explaining how the attack is performed, how simple the attack actually is (once you know the details), and how limited the resources (Computation and network) the attacker needs. Although it is not possible to cover the entire topic of hacker attacks in this article, I have simplified the rationale as much as possible and still provide as many necessary information as you can to understand the attack described.
Types of attacks
Later on you will learn more about the selected attack and how it is executed. But before you start the discussion, you need to understand some of the terminology in this area. Typically, attacks are categorized by their characteristics. Two of these features are described below:
Scanning: Scanning or tracking footprints (footprinting) is part of the hacker's initial information-gathering process. Before hackers can attack the system, they need to collect information about the system, such as network layout, operating system type, system available services, system users, and so on. Hackers can infer potential vulnerabilities based on the information they collect and choose the best attack method for the selected target system.
Denial of service attacks: Typically, hackers target specific systems and break into systems for specific purposes. The host security of those systems often prevents attackers from gaining control over the host. However, when a denial-of-service attack occurs, the attacker does not have to gain control over the system. The goal is to overload the system or the network so that they cannot continue to provide services. Denial of service attacks can have different goals, including bandwidth consumption (bandwidth consumption) and resource scarcity (resource starvation).
Agreement
This article discusses attacks on the Internet Control Message Protocol (ICMP) and transmission Protocol (TCP), both of which belong to the Internet Protocol (IP) series. Before delving into the details of these protocols, I intend to discuss them first in an environment that is appropriate for these protocols. Figure 1 shows a simplified diagram of the Internet Protocol (PROTOCOL) stack when Ethernet is assumed to be the underlying physical network technology.

Figure 1. Internet Protocol Stack
As shown in Figure 1, network protocols are usually layered. This makes sense because the underlying protocol provides very basic services, such as signal transmission on a network cable. In addition, higher-level protocols provide more sophisticated application-tier services, such as Telnet. Each layer uses the following layer of services, which enables the top-level protocol to transmit messages on the physical network. Let's briefly look at the protocol shown in Figure 1.
The two layers called the physical layer protocol handle the actual signal transmission on the network cable. The one-level protocol-Internet Protocol (IP)-uses this service.
The Internet Protocol (IP) provides a "host to host" package (or datagram) delivery service. IP provides the most basic form of datagram delivery between the boundaries of the underlying physical network. In turn, the IP layer provides services that are used by the Internetwork Control Message Protocol (ICMP) and transmission Protocol (TCP).
The Internet Control Message Protocol (ICMP) is an integral part of IP, but it uses certain IP services. ICMP provides services that allow hosts to communicate control information to each other. ICMP is used by IP and some higher level protocols, such as Transmission Control Protocol (TCP).
Transmission Control Protocol (TCP) is the third important agreement discussed in this article. TCP functions more than IP and provides two key features: connectivity and quality of service. This means that you can open a virtual channel between two hosts, through which the sequence of packets sent and their actual delivery are guaranteed.
The next higher level is the application layer protocol, such as Telnet and SMTP. They all use the services provided by TCP. For example, when you connect to a host with Telnet, open a connection, and you want all data entered into this Telnet session to be sent to the receiving host in the correct order.