3.3 Best Practice Procedures for Malware Removal
COMPTIA A+ CORE 2 - DOMAIN 3
Cyber Wizard
This article provides a structured approach to malware removal, covering detection, isolation, remediation, and preventive measures, as required for the CompTIA A+ exam.
CompTIA A+ Exam Domain: Domain 3.3 - Given a scenario, use best practice procedures for malware removal.
1. Investigate and Verify Malware Symptoms
Identifying malware symptoms is the first step in removal. Common signs include:
Slow system performance or high CPU usage.
Frequent pop-ups, browser redirections, or unwanted toolbars.
Antivirus software disabled or unable to update.
Unexpected network activity (e.g., high outbound traffic).
Unfamiliar processes running in Task Manager (taskmgr).
Unauthorized encryption of files (potential ransomware infection).
Diagnostic Tools:
Event Viewer (eventvwr.msc) – Review security logs for suspicious activity.
Task Manager (Ctrl + Shift + Esc) – Identify unknown running processes.
Autoruns (Sysinternals) – Lists startup programs that could be malicious.
Process Explorer – Checks for suspicious system activity.
2. Quarantine Infected Systems
To prevent malware from spreading, isolate the compromised system:
Disconnect from the network (both wired and wireless connections).
Restrict external device access to avoid malware replication via USB drives.
Disable file sharing in Control Panel > Network and Sharing Center.
Boot into Safe Mode (msconfig > Boot > Safe Mode) to limit malware execution.
3. Disable System Restore in Windows
Some malware hides in System Restore points and can reinfect the system after removal.
Open System Properties (sysdm.cpl).
Navigate to System Protection > Configure.
Select Disable system protection and confirm.
4. Remediate Infected Systems
Update Anti-Malware Software
Ensure antivirus/anti-malware software is up-to-date before scanning.
Recommended tools:
Windows Defender
Malwarebytes
ESET Online Scanner
Sophos Virus Removal Tool
Scanning and Removal Techniques
Boot into Safe Mode (Shift + Restart > Troubleshoot > Advanced Options > Startup Settings > Enable Safe Mode).
Run a full system scan using antivirus software.
Use preinstallation environments if malware prevents booting:
Windows Defender Offline (windowsdefender://scanoffline)
Bootable Rescue Disks (e.g., Kaspersky, Bitdefender, ESET Live CD).
Manually remove persistent threats:
Delete malicious files from %AppData%, %Temp%, and %ProgramData%.
Remove suspicious registry entries (regedit > HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run).
5. Schedule Scans and Run Updates
Enable automatic updates for antivirus and OS patches.
Configure scheduled full scans at least once per week.
Use real-time protection to prevent future infections.
Deploy network-based scanning for enterprise environments.
6. Enable System Restore and Create a Restore Point in Windows
Re-enable System Restore to allow recovery from future issues.
Open System Properties (sysdm.cpl) > System Protection.
Click Configure, then enable Turn on system protection.
Click Create to generate a new restore point.
7. Educate the End User
Preventing malware infections requires user awareness:
Recognizing phishing emails – Do not open attachments from unknown senders.
Avoiding untrusted downloads – Use only official sources.
Regular software updates – Keep OS and applications patched.
Using strong passwords – Implement multi-factor authentication (MFA).
Safe browsing habits – Use ad blockers and avoid suspicious websites.
Final Thoughts
Following best practices for malware removal ensures that systems are properly disinfected and secured. The CompTIA A+ exam evaluates an IT professional’s ability to diagnose malware infections, remove threats, and implement preventive measures to safeguard systems from future attacks.