exploit that service or exploit some security vulnerabilities present in the software running the service to infect the system.

In fact, it is a good practice to note all services running on different ports of a server and then remove the services that are not needed. For example, if we do not want remote access to a system, then we should remove services like FTP.

3. Alter default user accounts

Most operating systems come with some default user accounts. Some of these user accounts have administrative privileges. And some are meant for non-administrative users. These default accounts may provide additional privileges to a user than it is needed. And attackers can exploit the additional permissions easily to spread malware on the system. Hence, it is always a good practice to remove default accounts if possible or carefully review and alter the permissions of default accounts.

4. Apply the Principle of Least Privilege

The principle of least privilege is a concept as per which every user, program, or process is given the minimum access that is essential to perform the job or function. For example, if a user’s job is only to use a system for a particular purpose, then he should not have the right to install additional software on the system that requires administrative privileges.

The principle of least privilege is an essential concept in information security. It helps in reducing the cyber attack surface (What is an attack surface in cyber security?). Suppose a user does not have administrative privileges. In that case, the malware cannot exploit the system to gain privileged access unless the system has some other vulnerabilities.

In that way, the principle of least privilege helps in preventing the spread of malware also. If the malware cannot gain privileged access, it cannot move laterally or install and execute the malware on other systems easily.

Most operating systems separate tasks into those that require administrative privileges and those that do not. Hence, one should strictly enforce these roles, and a user or program should be given the least privileges that are needed to perform a task or job.

5. Regularly update an operating system

Attackers often exploit the security vulnerabilities present in an operating system or other software used on the system to infect the system. When we apply a patch or update the operating system and the software programs, the number of known vulnerabilities gets reduced. Security patches often address the known vulnerabilities present in an operating system or software. Hence, the more updated an operating system and software are, less are their known vulnerabilities.

And hence, we should update the operating system regularly.

6. Turn on logging and auditing

One should turn on the logging and auditing features in an operating system. For example, the operating system should log failed login attempts, administrative privileges being used, users logging in and out of the system, or changes made to …