CAS-004 Security Operations Practice Question
A security team is implementing a new endpoint detection and response (EDR) solution. The team wants to ensure the EDR can detect advanced threats that use fileless malware techniques. Which TWO of the following capabilities are MOST important for detecting fileless malware? (Choose two.)
⚠ Common exam trap
The trap here is assuming that traditional signature-based detection or vulnerability scanning can catch fileless malware, when in fact they are ineffective because fileless malware leaves no files on disk.
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
✓
Monitoring of PowerShell and Windows Management Instrumentation (WMI) activity
Fileless malware executes in memory using legitimate system tools, so detecting it requires monitoring of scripting and management interfaces like PowerShell and WMI, as well as analyzing in-memory process behavior and API calls. These capabilities allow EDR to identify malicious activity without relying on file signatures. The other options are either preventive measures or ineffective against fileless threats.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Disk encryption of the endpoint's hard drive
Why it's wrong here
Disk encryption protects data at rest in case of physical theft, but it does not detect or prevent fileless malware. Fileless malware operates in memory and does not rely on disk storage, so encryption has no impact on its detection. This capability is unrelated to the scenario's goal of detecting fileless malware.
- ✓
Monitoring of PowerShell and Windows Management Instrumentation (WMI) activity
Why this is correct
Fileless malware often uses built-in system tools like PowerShell and WMI to execute malicious code in memory without writing to disk. Monitoring these activities can detect suspicious command lines, encoded scripts, and unusual WMI events. This is critical because traditional file-based detection may miss such threats. EDR solutions that log and analyze PowerShell and WMI behavior can identify malicious patterns and block execution.
- ✗
Regular vulnerability scanning of the endpoint
Why it's wrong here
Vulnerability scanning identifies missing patches and misconfigurations but does not detect active fileless malware. It is a preventive measure, not a detection capability for fileless threats. While important for overall security, it does not directly help in detecting fileless malware that is already running in memory. Therefore, it is not a most important capability for this scenario.
- ✓
Analysis of in-memory process behavior and API calls
Why this is correct
Fileless malware resides in memory, so analyzing process behavior and API calls is essential. EDR solutions can monitor for suspicious API calls (e.g., CreateRemoteThread, VirtualAlloc) and anomalous process behavior, such as a process injecting code into another. This allows detection of malicious activity even when no file is written to disk. Memory analysis is a core capability for identifying fileless threats.
- ✗
Signature-based detection of known malware hashes
Why it's wrong here
Signature-based detection relies on matching file hashes or patterns of known malware. Fileless malware does not write files to disk, so there are no hashes to match. While signatures are still useful for known threats, they are ineffective against fileless techniques. Therefore, this capability is not most important for detecting fileless malware.
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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
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