mediumMultiple ChoiceObjective-mapped
Rootkit Remediation: Using System File Checker After Removal
A technician is troubleshooting a Windows 10 PC that was infected with a rootkit. After booting from a rescue disk and running a scan, the rootkit is removed, but the system is still unstable. What should the technician do next to ensure the system is fully remediated?
Quick Answer
The answer is to run the System File Checker (SFC) tool using the 'sfc /scannow' command. This is the correct next step because a rootkit infection often corrupts critical Windows system files to hide its presence, and even after successful removal, those damaged files remain, causing system instability. The SFC utility directly addresses this by scanning all protected system files and replacing any corrupted versions with cached copies from the Windows side-by-side store, thereby restoring file integrity. On the CompTIA A+ Core 2 220-1202 exam, this scenario tests your understanding of post-malware remediation procedures, where a common trap is assuming removal alone is sufficient—the exam emphasizes verifying system stability through file repair. A helpful memory tip is to think of SFC as the "cleanup crew" after the rootkit eviction: removal gets the intruder out, but SFC fixes the broken windows left behind.
⚠ Common exam trap
A common mix-up: candidates choose to reinstall the OS (Option A) because they assume any rootkit infection requires a full wipe, but the question specifies the rootkit is already removed and the remaining issue is instability from file corruption, making SFC the targeted remediation step.
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
✓
Run the System File Checker (SFC) tool to repair corrupted files.
After removing a rootkit, the system may have corrupted system files that cause instability. Running the System File Checker (SFC) tool with the 'sfc /scannow' command scans protected system files and replaces corrupted versions with cached copies from the Windows side-by-side store, directly addressing file integrity issues left by the rootkit.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Reinstall the operating system from scratch.
Why it's wrong here
While a clean install ensures removal, it is a last resort; the technician should first attempt to repair system files and check for remaining issues.
- ✓
Run the System File Checker (SFC) tool to repair corrupted files.
Why this is correct
SFC scans and repairs protected system files that may have been damaged by the rootkit, addressing the instability without a full reinstall.
- ✗
Disable System Restore and delete all restore points.
Why it's wrong here
This is a good practice to remove any infected restore points, but it does not fix current file corruption or instability.
- ✗
Perform a disk cleanup to remove temporary files.
Why it's wrong here
Disk cleanup frees up space but does not repair system files damaged by malware.
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Same concept, more angles
1 more way this is tested on 220-1202
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. A security analyst discovers that a user's workstation has been compromised by a rootkit that hides its processes from Task Manager. The rootkit is not detected by the installed antivirus. Which step is most effective for remediation?
hard- A.Run a full antivirus scan in Safe Mode.
- B.Use System Restore to revert to a previous state.
- ✓ C.Boot from a rescue disk and perform an offline antivirus scan.
- D.Reinstall the operating system from the recovery partition.
Why C: A rootkit that hides its processes from Task Manager and evades the installed antivirus operates at a deep level within the operating system, often in kernel mode. Booting from a rescue disk (e.g., a live CD/USB with an offline scanner) loads a clean operating system environment, preventing the rootkit from loading and allowing the antivirus to scan the infected system's files without interference. This offline approach is the most effective remediation step when the rootkit is actively hiding from the installed AV in the normal OS context.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1202 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 220-1202 exam.