How Ransomware Attacks Work — And How to Stop Them

5 min read · February 2025 · By IntrusionX Security Team

Ransomware is one of the most devastating forms of cybercrime — and it is growing rapidly in Australia. In 2024, ransomware attacks cost Australian organisations hundreds of millions of dollars in downtime, recovery costs and ransom payments. Understanding exactly how these attacks work is the first step to stopping them.

The Ransomware Attack Lifecycle

Ransomware attacks do not happen instantly. They follow a predictable sequence of stages — and each stage represents an opportunity to detect and stop the attack before it causes damage.

Initial Access

Attackers gain entry through a phishing email, malicious download, exposed remote desktop, or compromised credentials. This is the critical moment — if you stop it here, the attack fails.

Establishing Persistence

Once inside, the attacker installs backdoor software to maintain access even if you change passwords or reboot. They often stay hidden for days or weeks before activating the ransomware.

Lateral Movement

The attacker explores your network, identifies valuable data and backup systems, and moves to infect as many devices as possible to maximise damage and leverage.

Data Exfiltration

Modern ransomware groups often steal your data before encrypting it — giving them double leverage: pay, or we release your sensitive files publicly.

Encryption

The ransomware encrypts all targeted files using strong cryptography. Without the attacker's decryption key, your files are permanently inaccessible.

Ransom Demand

A ransom note appears demanding payment (usually in cryptocurrency) in exchange for the decryption key. There is no guarantee paying will restore your files.

Should you pay the ransom?

Law enforcement agencies including the Australian Federal Police advise against paying ransoms. Payment does not guarantee you will receive a working decryption key. It also funds further criminal activity and marks you as a willing payer — making you a target for repeat attacks.

How to Defend Against Ransomware

Effective ransomware defence requires multiple overlapping layers of protection — not a single product. Here is what a proper defence looks like:

Behavioural endpoint detection (EDR) — catches ransomware before it can encrypt files

24/7 SOC monitoring — detects unusual activity during the early stages of an attack

Automated device isolation — instantly quarantines infected machines to stop spread

Ransomware rollback technology — restores files to their pre-attack state within minutes

Phishing-resistant email filtering — blocks malicious emails before they reach inboxes

Multi-factor authentication — prevents compromised credentials from granting access

Network segmentation — limits the blast radius if an attacker does get in

Regular tested backups — your last line of defence if all else fails

Is your business protected against ransomware?

Get a free security assessment from IntrusionX. We'll identify your gaps and show you exactly how to close them.

Book a Free Assessment

Why Phishing Is the #1 Entry Point Why Your IT Provider Should Not Manage Security