Prevent Unauthorized Boot from Removable Media: Secure Boot and Application Control
A security team wants to reduce the chance that employees boot unmanaged tools from removable media and wants only approved software to run on laptops. Which two controls should they use? Select two.
Quick Answer
The answer is Secure Boot and application control or allowlisting. Secure Boot prevents unauthorized boot from removable media by verifying that only digitally signed, trusted firmware and bootloaders execute during startup, blocking unmanaged OS images from USB drives or other external devices. Application control or allowlisting complements this by restricting software execution to only pre-approved programs, ensuring that even if a system boots securely, no unapproved tools can run on the laptops. On the Security+ SY0-701 exam, this pairing tests your understanding of defense-in-depth at both the firmware and operating system layers—a common trap is confusing Secure Boot with full disk encryption or BIOS passwords, which do not control runtime software. Remember the memory tip: “Boot with Secure, run with Allow” to link Secure Boot to startup integrity and allowlisting to ongoing application enforcement.
⚠ Common exam trap
Many candidates confuse DNS forwarding (a network service) with DNS filtering or security controls, or think that a longer screen-lock timeout improves security, when in fact it weakens physical security by extending the window of opportunity for unauthorized access.
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
✓
Secure Boot
Secure Boot is correct because it ensures that only signed, trusted firmware and bootloaders execute during system startup, preventing unauthorized bootable media (e.g., USB drives with unmanaged OS images) from loading. This directly reduces the chance that employees can boot unmanaged tools from removable media by enforcing a chain of trust from UEFI firmware to the operating system kernel.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Secure Boot
Why this is correct
Secure Boot helps ensure the device starts using trusted boot components instead of unapproved pre-boot code. That reduces the risk of tampered boot media or rogue recovery tools.
- ✓
Application control or allowlisting
Why this is correct
Application control blocks unauthorized programs from running after the operating system starts. It is the best fit when the goal is to permit only approved software.
- ✗
DNS forwarding
Why it's wrong here
DNS forwarding routes name lookups to another resolver, but it does not stop untrusted boot media or control executable execution. It is unrelated to endpoint hardening.
- ✗
Longer screen-lock timeout
Why it's wrong here
A longer screen-lock timeout weakens physical security rather than improving it. It does not address boot integrity or application execution control.
- ✗
Public DNS resolvers
Why it's wrong here
Public DNS resolvers may improve name resolution in some cases, but they do not prevent unauthorized boot or application execution. They are not the correct hardening controls here.
Go deeper
Related to this question
Learn chapter
Cloud Security Fundamentals
Key term
Secure boot
Secure Boot is a security feature that ensures a device starts up using only trusted software that is digitally signed by the manufacturer.
Key term
Security
Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
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Same concept, more angles
4 more ways this is tested on SY0-701
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Several company laptops were found to boot from a removable drive containing an untrusted pre-boot utility before the operating system loaded. The security team wants to prevent unsigned or tampered boot code from starting. Which control is the best fit?
medium- ✓ A.Enable Secure Boot in firmware and block external boot devices where possible.
- B.Turn on screen lock after ten minutes of inactivity.
- C.Increase the password complexity policy for user accounts.
- D.Disable Windows Defender notifications on the endpoints.
Why A: Secure Boot is a UEFI firmware feature that verifies the digital signature of boot code against a trusted database before execution. By enabling Secure Boot and blocking external boot devices, the security team ensures that only signed, trusted bootloaders and drivers can run, preventing untrusted pre-boot utilities from loading. This directly addresses the scenario where laptops boot from a removable drive containing unsigned or tampered boot code.
Variation 2. Several corporate laptops occasionally boot from a removable drive containing an untrusted recovery tool before Windows loads. The security team wants to reduce the chance of pre-boot tampering and unauthorized boot media use. Which two controls are most effective? Select two.
medium- ✓ A.Enable UEFI Secure Boot.
- ✓ B.Disable booting from external media or protect the firmware setup with a password.
- C.Keep local administrator rights so users can recover faster.
- D.Turn off disk encryption because it slows startup.
- E.Move the laptops to a different subnet.
Why A: UEFI Secure Boot ensures that only signed, trusted bootloaders and drivers are executed during the boot process, preventing unauthorized boot media from loading. Additionally, disabling boot from external media directly prevents the system from attempting to boot from removable drives, and protecting firmware setup with a password prevents unauthorized changes to boot order. Together, these controls reduce pre-boot tampering and unauthorized boot media use.
Variation 3. A security team discovers that several laptops occasionally boot from a removable drive before Windows loads, allowing unapproved recovery tools to run. Management wants to prevent this with the least impact on normal users. Which control is the best fit?
medium- A.Disable all USB ports permanently on every laptop.
- ✓ B.Enable secure boot and restrict the firmware boot order so only the approved internal boot path is allowed.
- C.Uninstall the endpoint protection agent and replace it with manual inspections.
- D.Move user data to cloud storage so rogue boot media can no longer access it.
Why B: Secure Boot ensures that only signed, trusted firmware and bootloaders execute during the startup process. By restricting the firmware boot order to the internal drive only, the laptop will ignore removable media during boot, preventing unapproved recovery tools from running before Windows loads. This has minimal impact on normal users because they can still use USB devices after the OS has booted.
Variation 4. A laptop repeatedly starts with an unapproved bootloader, and the security team wants the firmware to refuse boot code that is not signed by a trusted key. Which feature should be used?
easy- ✓ A.Secure Boot.
- B.BitLocker full-disk encryption.
- C.A DHCP reservation.
- D.A local administrator password policy.
Why A: Secure Boot is a UEFI firmware feature that verifies the digital signature of bootloaders and kernel code against a database of trusted keys before allowing execution. By configuring Secure Boot to only accept boot code signed by a trusted key, the firmware will reject any unapproved bootloader, preventing unauthorized code from running during the boot process.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SY0-701 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 SY0-701 exam.