Linux is a multi-user operating system. When each user logs into the system, they have a dedicated runtime environment. Typically, the default environment for each user is the same, which is essentially a set of environment variable definitions. Users can customize their runtime environment by modifying the corresponding system environment variables. If /etc/profile is maliciously modified, it can cause services to become unavailable.
If the host /etc/profile has been modified, carefully check the host environment to determine if there has been an intrusion and change the host user passwords.