200-201 Security Concepts Practice Question
A security analyst is examining a memory dump from a compromised host and finds a small piece of code that resides only in memory, has no corresponding file on disk, and injects itself into a running legitimate process. The code does not replicate to other systems. Which type of malware best describes this?
⚠ Common exam trap
The trap here is equating any memory-resident code with a rootkit, when the absence of disk files and process injection specifically point to fileless malware.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A fileless malware that operates in memory and injects into processes
Fileless malware operates entirely in memory, often by injecting into legitimate processes, and leaves no file on disk. This makes it difficult to detect with traditional file-based antivirus. The absence of a disk file and the process injection behavior are the defining characteristics, distinguishing it from worms, trojans, and rootkits, which typically involve files or kernel modifications.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
A fileless malware that operates in memory and injects into processes
Why this is correct
Fileless malware resides in memory, often using PowerShell, reflective DLL injection, or process hollowing, and leaves little or no trace on disk. It typically injects into legitimate processes to evade detection. The scenario matches these characteristics: no file on disk, memory-resident, and process injection, without self-replication to other systems.
- ✗
A worm that spreads across the network
Why it's wrong here
A worm is self-replicating and spreads to other systems without user interaction, often leaving files or creating new processes on multiple hosts. The described code has no file on disk and does not replicate, which contradicts worm behavior. The focus here is on memory-resident, process-injecting code, not network propagation.
- ✗
A rootkit that hides its presence by modifying the kernel
Why it's wrong here
A rootkit is designed to conceal its presence, often by altering system calls or kernel structures, and may persist on disk. While fileless malware can use rootkit-like techniques, the scenario does not describe kernel modification or concealment mechanisms. The key traits are memory-only execution and process injection, which are hallmarks of fileless malware.
- ✗
A trojan that disguises itself as legitimate software
Why it's wrong here
A trojan masquerades as legitimate software to trick users into executing it, but it usually exists as a file on disk. The scenario explicitly states there is no corresponding file on disk and the code is memory-resident, which is not the defining trait of a trojan. Process injection is also not a core characteristic of trojans.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 200-201 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-201 exam.