WINDOWS system backdoor instance 4

Telnet spoofing, the most easily overlooked Backdoor

Telnet is a remote logon tool under the command line, but it is often ignored by the Administrator when it is used for server management. If attackers enable remote desktop for remote control after controlling a server, it is easy for administrators to detect the remote control, but it is not easy to detect when Telnet is enabled. However, the default port for telnet is 23. If it is enabled, it is easy for others to scan. Therefore, attackers can change the port for telnet to exclusively control the server.

1) modify the port

To modify the telnet port of a Windows 2003 Server locally, run the command "Start> Run" And Enter cmd to open the command prompt, run the "tlntadmn config port = 800" 800 command to set the modified telnet port. To avoid port conflict, you do not need to set the port to a known service .) Of course, you can also remotely modify the telnet port of the server and enter the "tlntadmn config \ 192.168.1.9 port = 800-u gslw-p test168" \ 192.168.1.9 peer IP address at the command prompt, port = 800 is the telnet port to be modified.-u specifies the user name of the other party and-p specifies the password of the other user .) Figure 7)

2) Remote Logon

Run the command "telnet 192.168.1.9 800" and then enter the user name and password to record the password to telnet to the server.

3) Preventive measures

The telnet backdoor method is very simple. You can use the "tlntadmn config port = n" command to change the port, Run "services. msc" more thoroughly to open the Service Manager and disable the telnet service. Figure 8)

No matter how varied the types of backdoors are, there is a common feature-concealment, which is invisible to the sun. As long as you master certain system technologies and are always vigilant, the backdoor will be visible. Knowing the principles of webshells can fundamentally end webshells.

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