Classification of vulnerabilities

According to the formation of the loopholes, the vulnerabilities can be divided into the loopholes of program logic structure, the error of program design, the loopholes caused by open protocol and human factors.

According to the situation that the vulnerability is mastered, the vulnerability can be divided into known vulnerabilities, unknown vulnerabilities and 0day and several other types. Program Logic Structure Vulnerability

This type of vulnerability is likely to be a procedural logic flaw in programmers writing programs because of unreasonable or incorrect logic design of the program. This type of vulnerability is most typical of Microsoft's Windows 2000 user login's Chinese Input method vulnerability. Non-authorized personnel can bypass Windows user name and password authentication with the highest permissions of the computer from the input method of the login interface.

This type of vulnerability could also be a legitimate application used by hackers to do improper use. This type of vulnerability is most typically referred to in the following case, the WinRAR self-extracting function, the programmer's intention is to facilitate the user's use, so that users without WinRAR installation can also extract compressed files in this way. But this function has been used by hackers for improper purposes.

This vulnerability may be easier to understand with a metaphor. For example, you open a door and open a dog hole in the door, specifically for the dog's convenience. Under normal circumstances, people should use the key to open the lock in order to come in.  But there was this guy. He found that using a trick person can also get in and out of a dog hole, and the way to get in and out of a dog hole can be seen as a security breach. Programming Error Vulnerabilities

Another type of vulnerability is the vulnerability of programmers as a result of technical negligence in writing programs. This type of vulnerability is most typically a buffer overflow vulnerability, which is one of the most exploited types of vulnerabilities by hackers.  This buffer overflow vulnerability is described in detail in the following sections. Vulnerabilities caused by open protocols

At present, the Internet communication is based on an open TCP/IP protocol. Because the original designer of TCP/IP protocol designed the communication protocol, only considered the practicality of the Protocol, but did not take into account the security of the Protocol, so there are many loopholes in the TCP/IP protocol. For example, using the TCP/IP protocol open and transparent sniffing network packets, stealing the user password and password information inside the packet, TCP protocol three handshake potential defects caused by the denial of service attacks.  Some examples of exploits that exploit TCP/IP protocol vulnerabilities are described in the following sections. A loophole caused by human factors

If a system itself is designed to be perfect, security is also very high, but the security awareness of managers is weak, the same will leave the system loopholes. For example, the system itself is perfectly secure, however, the system login required Administrator account or password, but because the setting is too simple and the hacker guessed out, then other links again security does not have the slightest meaning; or although the administrator has set a very complex password, but he wrote the password on a piece of paper,  and throw them in the wastebasket, it is also possible to cause the system to be compromised by hackers. Known vulnerabilities

Known vulnerabilities are open vulnerabilities that have been discovered and widely disseminated by people. This type of feature is the cause of the vulnerability and the use of the method has been a large number of security organizations, hackers and hacker organizations have mastered. Security Organizations or vendors add protective methods for the appropriate types of vulnerabilities in their security products or security services, in accordance with the causes and methods of disclosure of vulnerabilities. Hackers and hacker organizations use the published vulnerabilities to form the cause, write specific targeted vulnerabilities to use Program files, and can bypass security protection software. For example, for an IE browser version of IE vulnerability to use files, or they simply use some of the vulnerabilities of the site to disclose the vulnerability of the use of the program file without any modification to attack the computer on the Internet.

Developers of vulnerable software will patch up the programs they develop to patch up software that has already been compromised, for information about vulnerabilities that are exposed. Unknown vulnerability

Unknown vulnerabilities are those that already exist but have not yet been discovered, and this type of vulnerability is characterized by the fact that, although they are not discovered, they are objectively present, and they bring hidden threats to the computer network security. If they are found by hackers intentionally or unintentionally, it will pose a great threat to the security of computer network.

So software developers, security organizations, hackers and hackers are all trying to find vulnerabilities, you can say who first discovered the vulnerability, who can grasp the initiative. If the software developers and security organizations first discovered the vulnerabilities, they can take the initiative in security protection, if the hackers or hackers to identify the vulnerabilities first, they can take the initiative in the attack.  0day vulnerabilities       So-called 0day vulnerabilities are vulnerabilities that have been uncovered but have not been spread widely, meaning that this type of vulnerability may be in the hands of a handful of people. Hackers are likely to use this time lag to attack the target machine they want to attack when the information on this type of vulnerability is not yet widespread, because the vast majority of users have not yet acquired the relevant vulnerability information or defense, and it is easy for a hacker to succeed.