What has most likely occurred if the ls, su, and ps commands no longer function as expected?

The scenario described suggests the possibility of a root kit being installed on the system. A root kit is a type of malicious software designed to gain unauthorized access to a computer and modify the system in such a way that the malware becomes hidden from traditional security methods, including system command usage.

When commands such as ls (which lists files in a directory), su (which allows a user to switch to another user), and ps (which displays currently running processes) no longer function properly, it indicates that the integrity of the operating system may have been compromised. Specifically, root kits can alter system binaries or modify system calls to conceal their presence and evade detection or disruption while disrupting normal system functionalities.

This disruption can lead to irregularities when executing standard commands, as the root kit manipulates how these commands operate, providing false outputs or failing to execute altogether. In contrast, the other options do not typically lead to widespread command failure in this manner:

• A Trojan often disguises itself as legitimate software but doesn't usually interfere with system commands directly.

• SQL injection primarily targets database interactions and would not directly affect command-line utilities.

• Spyware focuses on covertly gathering user information and may cause some issues, but it generally does not disable system commands.

Therefore, the