CS0-003 Security Operations Practice Question
An analyst examines a memory dump from a compromised host and finds that 'svchost.exe' is executing code from a memory region that is not backed by any executable file. What technique is most likely being used?
⚠ Common exam trap
CS0-004 often tests whether candidates can distinguish process hollowing (original image unmapped, unbacked executable region) from DLL injection (host image intact, extra DLL loaded) — the phrase 'not backed by any executable file' is the tell for hollowing.
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
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Process hollowing
Process hollowing involves creating a legitimate process (often svchost.exe) in a suspended state, unmapping its original executable image from memory, and replacing it with malicious code. The result is a process whose in-memory code is not backed by any executable file on disk, which is exactly what the memory dump shows. Reflective DLL injection and classic DLL injection leave the host image intact and load a DLL into it.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Reflective DLL injection
Why it's wrong here
Reflective DLL injection bypasses standard Windows API loading mechanisms by mapping a DLL directly into a target process's memory space and executing its entry point. While this technique avoids writing the DLL to disk, the injected payload still retains its PE (Portable Executable) structure and header characteristics. It does not involve unmapping a legitimate process's entire executable memory space to replace it with a completely different, unbacked payload.
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API hooking
Why it's wrong here
API hooking modifies the control flow of specific function calls within a process, typically by inserting jumps (trampolines) or modifying import address tables to redirect execution to malicious monitoring code. This technique is used to intercept and alter data in transit rather than replacing the entire memory image of a running process. Consequently, it does not result in a completely unbacked executable memory region replacing a legitimate process image.
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Process hollowing
Why this is correct
Process hollowing involves spawning a legitimate system process in a suspended state, unmapping its original executable memory using APIs like NtUnmapViewOfSection, and writing malicious code into the hollowed-out space. Because the malicious payload is written directly into the allocated memory of the victim process without being loaded from a corresponding file on disk, memory analysis reveals executable regions that lack proper file backing. This allows the malware to masquerade as a trusted system process.
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DLL injection
Why it's wrong here
Standard DLL injection forces a target process to load a malicious library, typically by using the CreateRemoteThread API to call LoadLibrary with a path to a DLL on disk. This technique leaves a distinct footprint because the injected DLL is registered as a loaded module within the process's Process Environment Block (PEB) and is backed by a physical file on the filesystem. It does not replace the primary executable image of the host process with unbacked memory.
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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 CompTIA exam blueprint
This CS0-004 practice question is part of Courseiva's free CompTIA 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 CS0-004 exam.