GSEC Malicious Code and Exploit Mitigation Practice Question
Which security control is most effective at preventing the execution of unauthorized or malicious software by enforcing a 'deny-by-default' policy on a workstation?
⚠ Common exam trap
Candidates often choose 'Antivirus' or 'Endpoint Detection and Response (EDR)' because they are common tools, forgetting that these are often signature-based and do not inherently implement a strict 'deny-by-default' execution policy.
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
✓
Application Whitelisting (e.g., AppLocker or WDAC).
Application whitelisting (or Application Control) prevents any program from running unless it is explicitly permitted by a defined policy. This is vastly superior to blacklisting, which can only block known threats. In a professional environment, this controls the execution environment, significantly reducing the attack surface by ensuring that only vetted and approved binaries, scripts, and installers can run, effectively mitigating zero-day threats and unauthorized utility usage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Endpoint Detection and Response (EDR) agents.
Why it's wrong here
EDR agents are designed to monitor and alert on suspicious behavior after it occurs. While they provide excellent visibility and response capabilities, they do not inherently block unauthorized software from launching unless the specific binary has already been flagged as malicious by the vendor's threat intelligence database.
- ✗
Next-Generation Antivirus (NGAV) with behavioral analysis.
Why it's wrong here
NGAV relies on heuristic or behavioral engines to identify malicious activity. While highly effective against known and some unknown threats, it still operates on a permissive model where new, unknown files are often allowed to run until they exhibit malicious behavior, failing the 'deny-by-default' security requirement.
- ✓
Application Whitelisting (e.g., AppLocker or WDAC).
Why this is correct
Application whitelisting explicitly restricts execution to only approved binaries, scripts, and installers. By implementing a default-deny policy, it ensures that any unauthorized or malicious software—regardless of whether it is known to security vendors—will be blocked from executing on the host, providing a robust security posture.
- ✗
Host-based Intrusion Prevention System (HIPS).
Why it's wrong here
HIPS monitors system calls and network traffic for exploit signatures. While it can block some malicious activities, it is not a primary tool for restricting software execution. It lacks the granular policy control required to implement a strict 'deny-by-default' software execution environment for end-user workstations.
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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 GIAC exam blueprint
This GSEC practice question is part of Courseiva's free GIAC 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 GSEC exam.