Best Immediate Containment Action for Active Ransomware: Network Isolation
Exhibit
EDR event timeline: 14:02:11 excel.exe spawned powershell.exe with -enc parameter 14:02:13 powershell.exe created scheduled task: "OneDrive Update" 14:02:18 explorer.exe began renaming multiple .docx files to .lock 14:02:21 outbound HTTPS connection to 198.51.100.77:443 14:02:24 security service attempted to terminate, then recovered
Based on the exhibit, what is the BEST immediate containment action?
The workstation is still powered on, and the user reports that files are being renamed and the system is running very slowly. The security analyst confirms malicious activity is in progress.
Quick Answer
The answer is immediate network isolation, specifically using EDR containment or switch quarantine. This is the best immediate containment action for active ransomware because it severs the workstation’s Layer 2 connectivity, stopping file renaming, lateral spread, and command-and-control communication while preserving volatile memory for forensic analysis—unlike powering off, which can trigger destructive payloads and destroy evidence. On the Security+ SY0-701 exam, this scenario tests your understanding of incident response priorities under CompTIA’s “containment, eradication, recovery” framework; a common trap is choosing to power off the system, which seems intuitive but violates forensic best practices. Remember the mnemonic “Isolate, don’t annihilate”—cut the network link first, never pull the plug.
⚠ Common exam trap
CompTIA often tests the distinction between containment (stopping the spread) and eradication (removing the threat), tempting candidates to choose power-off or uninstall actions that destroy evidence or fail to stop active malicious processes.
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
✓
Immediately isolate the endpoint from the network using EDR containment or switch quarantine.
The immediate priority is to stop the active malicious activity (file renaming, system slowdown) by severing the workstation's network connectivity. EDR containment or switch quarantine isolates the endpoint at Layer 2, preventing the attacker from exfiltrating data, communicating with command-and-control servers, or spreading laterally, while preserving volatile memory for forensic analysis. This is faster and more controlled than powering off, which destroys evidence and may trigger destructive payloads.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Immediately isolate the endpoint from the network using EDR containment or switch quarantine.
Why this is correct
Isolating the endpoint via EDR containment or switch quarantine halts active malicious activity and lateral movement while preserving volatile memory and forensic evidence. Immediate network isolation is the fastest containment action for a live infection, unlike powering off, which destroys memory-resident evidence.
- ✗
Power off the workstation immediately to prevent any further file changes.
Why it's wrong here
Powering off destroys volatile memory, losing running processes and indicators needed for forensics, and does not guarantee containment. It is tempting as an instinctive way to halt file changes, yet network isolation preserves memory while stopping spread, making it the standard immediate action.
- ✗
Uninstall Microsoft Office so the malicious spreadsheet cannot launch again.
Why it's wrong here
Removing Office leaves the running malware, renamed files and slow system untouched, so containment fails. It is tempting because the malicious spreadsheet is the delivery vector, and application removal would be sensible during later eradication and hardening once the host is isolated and the infection cleared.
- ✗
Block the destination IP address at the firewall and wait for the user to log off.
Why it's wrong here
Blocking one destination IP leaves the endpoint executing malware, so file renaming continues while awaiting logoff. It is tempting because firewall blocks are valid containment for command-and-control egress, but here the malicious process is already resident and must be isolated at the host.
Go deeper
Related to this question
Learn chapter
ICS and SCADA Security Threats
Key term
EDR
Endpoint Detection and Response (EDR) is a cybersecurity technology that continuously monitors endpoint devices to detect, investigate, and respond to advanced threats.
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
1 more way 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. Based on the exhibit, what is the MOST likely activity taking place on the network? A user opened a spreadsheet shortly before unusual internal connection patterns began. The same account is now authenticating to many hosts in rapid succession.
hard- A.A worm is flooding the network with broadcast traffic and exhausting bandwidth.
- ✓ B.An attacker is performing lateral movement using stolen credentials and remote administration tools.
- C.A malicious insider is exfiltrating data through a cloud sync application.
- D.A misconfigured printer is repeatedly scanning the subnet for available services.
Why B: The exhibit shows a user opening a spreadsheet (likely a phishing vector) followed by rapid authentication attempts from the same account to many hosts. This pattern matches lateral movement using stolen credentials, where an attacker uses remote administration tools like PsExec, WinRM, or RDP to move across the network after initial compromise.
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.