Which of the following best describes a stealth virus?

The best description of a stealth virus is that it hides from the operating system. Stealth viruses are designed specifically to evade detection by concealing their presence. They achieve this by intercepting system calls and altering the way the operating system views the files they infect. Rather than modifying the files directly in a way that is easily detectable, a stealth virus may work by temporarily removing itself from visibility when a scan is performed, making it challenging for antivirus software to identify and eliminate it.

In contrast, while some viruses may constantly change their code to obscure their identity, this behavior is more characteristic of polymorphic and metamorphic viruses rather than a stealth virus specifically. Additionally, the notion that a stealth virus requires manual execution does not align with the typical behavior of stealth viruses, which can execute independently without user intervention. Lastly, the statement about targeting only mobile devices is inaccurate, as stealth viruses can affect various operating systems, not limited to mobile platforms. Overall, the primary characteristic that defines a stealth virus is its ability to conceal itself from detection mechanisms within the system.