What is a cyber hacker? What are the common attack methods used by hackers?

Cyber ​​hackers are people with superb programming skills, a strong desire to solve problems and overcome limitations, people who are good at IT technology, computer scientists, and people with a high understanding of computer science, programming and design. Commonly used attack methods include: planting viruses, email attacks, network monitoring, finding system vulnerabilities, backdoor programs, denial of service, etc.

The operating environment of this tutorial: Windows 10 system, DELL G3 computer

What is a network hacker?

Cyber ​​hackers are people who have superb programming skills, a strong desire to solve problems and overcome limitations, are good at IT technology, computer scientists, and have a high level of understanding of computer science, programming and design. people.

Hacker, originally derived from the English hacker, had a positive connotation in the American computer industry in the early days. They are all highly skilled computer experts, especially programmers, which is a general term.

Hongke, a Hongke who safeguards national interests and represents the will of the people of the motherland, loves his motherland, nation, and peace, and strives to safeguard national security and dignity.

Lanke, hackers who believe in freedom and advocate patriotism, use their own power to maintain peace on the Internet.

Hacker is the transliteration of "Cracker", which means "cracker". Engaged in malicious cracking of commercial software and malicious intrusion into other people's websites. Similar to hackers, in fact, hackers and hackers are essentially the same, those who break into computer systems/software. There is not a very clear boundary between hackers and "crackers", but as the meanings of the two become increasingly blurred, the public's treatment of the two meanings has become less important.

Commonly used attack methods by hackers

Hacker attack methods can be divided into two categories: non-destructive attacks and destructive attacks. Non-destructive attacks are generally intended to disrupt the operation of the system without stealing system data, and usually use denial-of-service attacks or information bombs; destructive attacks are intended to invade other people's computer systems, steal system confidential information, and destroy the data of the target system.

1. Planting viruses

Virus programs are latent and will have a long-term impact on the security of personal information. In the past, viruses were mainly common on computers. Now with the popularity of mobile phones, there are many viruses on mobile devices.

Viruses do not actively attack personal devices. They are often hidden in web pages and software. They are implanted after users click and install them. As long as the device is connected to the Internet, the virus program will automatically collect the information. Report to hackers.

Viruses are also being updated. Many advanced viruses are difficult to detect and kill with ordinary software. There are even viruses hidden in regular anti-virus software, making it difficult for you to prevent them.

2. Email attacks

E-mail attacks mainly manifest themselves in two ways: one is email bombing and email "snowballing", which is commonly referred to as email bombs. It is to use forged IP addresses and email addresses to send thousands, tens of thousands or even infinite times of spam emails with the same content to the same mailbox, causing the victim's mailbox to be "bombed", and in severe cases, the email server may be operated. The system brings danger or even paralysis; the second is email spoofing, where the attacker pretends to be the system administrator (the email address is exactly the same as the system administrator) and sends an email to the user asking the user to change the password (the password may be a specified string) Or load viruses or other Trojan programs in seemingly normal attachments (as far as the author knows, network administrators in some units have the obligation to regularly send free firewall upgrade programs to users, which provides an opportunity for hackers to successfully use this method. ), this type of deception is generally not very harmful as long as users are vigilant.

3. Network monitoring

Network monitoring is a working mode of the host. In this mode, the host can receive all the information transmitted on the same physical channel in this network segment. Regardless of who is the sender or recipient of these messages. At this time, if the communication information between the two hosts is not encrypted, you can easily intercept the information including passwords and accounts by using some network monitoring tools, such as NetXray for windows 95/98/nt, sniffit for linux, solararies, etc. Information. Although the user accounts and passwords obtained through network monitoring have certain limitations, listeners can often obtain all user accounts and passwords on the network segment where they are located.

4. System vulnerabilities

Many systems have security vulnerabilities (Bugs) of one kind or another, some of which are inherent in the operating system or application software itself, such as Sendmail vulnerabilities, sharing in win98 Directory password verification vulnerabilities and IE5 vulnerabilities, etc. These vulnerabilities are generally difficult to prevent hackers from destroying before patches are developed, unless you unplug the network cable; there are also some vulnerabilities caused by system administrator configuration errors, such as in the network In the file system, calling out directories and files in a writable manner, and storing unshadowed user password files in a certain directory in clear code will give hackers an opportunity and should be corrected in time.

5. Backdoor program

When programmers design some programs with complex functions, they generally use modular programming ideas to divide the entire project into multiple functional modules for design and debugging respectively. The backdoor at this time is the secret entrance of a module. During the program development phase, backdoors facilitate testing, changing, and enhancing module functionality. Under normal circumstances, after completing the design, the backdoors of each module need to be removed. However, sometimes due to negligence or other reasons (such as leaving them in the program for future access, testing or maintenance) the backdoors are not removed, and some people with ulterior motives will use exhaustive methods. The search method discovers and exploits these backdoors, then enters the system and launches an attack.

6. Information bomb

Information bomb refers to the use of some special tools and software to send a large amount of information exceeding the system load to the target server in a short period of time, causing the target server to be overloaded, network blocked, and the system crashed. means of attack. For example, sending a specific combination of UDP data packets to an unpatched Windows 95 system will cause the target system to crash or restart; sending a specific data packet to a certain model of router will cause the router to crash; sending a large number of spam emails to someone's email will This mailbox is "exploding" and so on. Common information bombs currently include email bombs, logic bombs, etc.

7. Denial of Service

Also called a distributed D.O.S attack, it uses a large number of data packets that exceed the processing capabilities of the attacked target to consume the available system and bandwidth resources of the system, and finally paralyzes the network service. A means of attack. As an attacker, you first need to invade and control a website through conventional hacking methods, and then install and start a special command on the server that can be issued by the attacker to control the process. The attacker issues the IP address of the attack target as a command to the process. , these processes begin to attack the target host. This method can concentrate a large amount of network server bandwidth to attack a specific target, so it is very powerful. In an instant, the bandwidth resources of the attacked target can be exhausted, causing the server to paralyze. For example, the hacker attack on the University of Minnesota in the United States in 1999 fell into this method.

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