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Photo: Lenharth Systems (CC0)
Spotlight
PAGE: https://alison.com/course/introduction-to-computer-network-security-revised
PROMISE: Understand authentication and risk layers to isolate critical data from local attacks.
WHO: IT managers seeking foundational concepts to audit local network exposure risks.
WHYNOW: Free access allows teams to update security knowledge before major infrastructure changes.
DESC: In this online network security course, learn about the concepts of network security, ranging from appropriate password creation to complex security principles.
BEFORE: Backups sit on the same switch as production servers.
BEFORE: All staff share broad network access rights.
BEFORE: Security relies on simple password rules.
AFTER: Risk management concepts guide segmentation of backup systems.
AFTER: Windows permissions limit user reach into sensitive areas.
AFTER: Stronger authentication methods protect network entry points.
GAIN: A clear structure for evaluating risk in local network design.
GAIN: Practical Windows permission settings to limit lateral movement.
GAIN: Knowledge of complex password standards and authentication types.
STEP: You list shared drives but lack a clear framework for evaluating exposure. || List the four parts of risk management || Apply these parts to identify where local backup systems create single points of failure.
STEP: Ransomware moves laterally because user permissions are too broad on the LAN. || Describe how to set permissions and rights for your users in a windows operating system || Reduce unnecessary local access that allows threats to reach your primary and backup media.
STEP: Employees reuse weak credentials that make network-wide compromise easy. || Explain how to create a complex password || Establish stronger credential standards that limit how easily attackers enter the network.
STEP: You rely on shared logins for remote access into sensitive folders. || Explain the different methods of authentication || Select more robust verification methods to protect entry points into the data zone.
NOTFOR: Teams needing immediate software solutions for air-gapped backup hardware.
NOTFOR: Administrators without the time for a beginner level course of 1.5 to 3 hours.
FACT: Average duration: 1.5-3 Hours (Contains Video)
FACT: CPD-accredited certificate available
FACT: Beginner level
COVERS: Discuss the core principles of security
COVERS: List the four parts of risk management
COVERS: Describe the different layers of physical security
COVERS: Explain the different methods of authentication
COVERS: Describe how to set permissions and rights for your users in a windows operating system
COVERS: Describe the different types of password attacks
COVERS: Explain how to create a complex password
COVERS: Computer Networking
COVERS: Network Security
COVERS: Security
COVERS: Transition Year Top Ups and Tasters
MODULE: Understanding Security Layers || Introduction | Core Security Principles | Physical Security
MODULE: Authentication, Authorization, and Accounting || Authentication | Authorization | Audit and Encryption
MODULE: Understanding Security Policies || Common Password Attacks | Password Policies
What you are probably seeing
Restore tests fail silently, or the backup software reports success while the data on the disk is already encrypted.
The backup server shares the same IP range and network segment as the production files, so the malware spreads to both simultaneously.
Why it happens
Security teams often treat network reachability as a convenience, ignoring that shared infrastructure creates a single point of failure.
Operators assume cloud or NAS backups are inherently safe, not realizing that connectivity is enough for ransomware to propagate.
What changed recently
2026-10-06 · Group-IB’s August 2026 APAC Ransomware Data: What 190 Incidents Actually Tell You
Group-IB data highlights the gap for air-gapped backups:
• 190 incidents hit APAC in August 2026.
• Ransomware grew 26.7 percent month over month.
• The Gentlemen group claimed 37 of these cases.
Source: how_devto_security
2026-10-06 · Ransomware Recovery | Guide to Restoring Data, Systems, and Operations After an Attack (2026)
DeXpose is now mapping recovery paths for that gap:
• 90% of organizations report confidence in backup recovery.
• Sophos found cybercriminals targeted backups in 94% of attacks.
• Only 26% with compromised backups recovered within one week.
Source: DeXpose
Step by step
1. Disconnect the backup server from the live network and verify it only powers on during scheduled window tasks.
2. Run a full restore test from the offline media into an isolated environment to prove the files are not encrypted.
3. Enable immutable retention policies on the storage system so that files cannot be deleted or altered for a set period.
4. Document a manual air gap procedure that physically removes the storage media from the network at least once a week.
5. Rotate backup credentials and ensure the backup service account does not have administrator rights on the source systems.
Ways to go further
Start here: Introduction to Computer Network Security For when you want to audit local network exposure risks. Open the free course on Alison ↗
Better fit: Computer Networking – Digital Network Security For when you are planning new infrastructure for data protection. Open the free course on Alison ↗
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