The company should take immediate action to prevent further damage and investigate the incident. The first step is to disable the user's account and inform the security team. Disabling the user's account can prevent unauthorized access to the external database by the attackers, who may use the stolen credentials to log in and manipulate or steal dat a. Informing the security team can alert them of the breach and allow them to take appropriate measures, such as scanning for malware, changing passwords, notifying other users, and reporting the incident34.

Port 22 is used for SSH (Secure Shell), which is a secure and encrypted protocol for remote access to a server. Port 23 is used for Telnet, which is an insecure and unencrypted protocol for remote access. Port 990 is used for FTPS (File Transfer Protocol Secure), which is a secure and encrypted protocol for file transfer. The administrator should open port 22 and close port 23 to enable SSH and disable Telnet, as SSH is more secure and reliable than Telnet. The administrator does not need to open port 990, as FTPS is not required for making configuration changes123.
References = 1: Remote Desktop - Allow access to your PC from outside your network(https://learn.microsoft.com/en-us/windows-server/remote/remote-desktop-services/clients/remote-desktop-allow-outside-access) 2: Test remote network port connection in Windows 10 - Winaero(https://winaero.com/test-remote-network-port-connection-in-windows-10/) 3: Windows Command to check if a remote server port is opened?(https://superuser.com/questions/1035018/windows-command-to-check-if-a-remote-server-port-is-opened)

The HCL stands for Hardware Compatibility List and it is a list of hardware devices that are tested and certified to work with a specific operating system. If a network card is not on the HCL for the OS, it may not function properly or cause compatibility issues. Therefore, verifying the network card is on the HCL for the OS should be the next step to troubleshoot this issue. References: https://www.comptia.org/training/resources/exam-objectives/comptia-server-sk0-005-exam-objectives (Objective 4.1)

Port 21 is used for FTP (File Transfer Protocol), which is a protocol that transfers files between servers and clients in cleartext, meaning that anyone can intercept and read the data. To stop this communication, port 21 should be closed on the web server and replaced with a secure protocol, such as SFTP (Secure File Transfer Protocol) or FTPS (File Transfer Protocol Secure), which use encryption to protect the data. Verified Reference: [FTP vs SFTP vs FTPS]

The server administrator should use cable management to prevent network connectivity loss when pulling a server from the rack during maintenance. Cable management is a practice of organizing and securing the cables that connect various devices and components in a system. Cable management can help improve airflow, reduce clutter, prevent tangling, and avoid accidental disconnection or damage of cables. Cable management can be done using various tools and techniques, such as cable ties, cable trays, cable labels, cable organizers, or cable ducts.