Ransomware is one of the most damaging forms of cybercrime facing businesses today. It can lock you out of your own systems, encrypt your files, and demand payment for their release — all within minutes. Understanding how it works and how to defend against it is essential for any business that relies on technology.
What Is Ransomware?
Ransomware is a type of malicious software (malware) that encrypts files on a victim's device or network, making them inaccessible. The attacker then demands a ransom — typically paid in cryptocurrency — in exchange for the decryption key needed to restore access. There is no guarantee that paying the ransom will result in file recovery.
How Does Ransomware Spread?
Ransomware typically enters a system through one of these methods:
- Phishing emails – Deceptive messages containing malicious links or attachments.
- Malicious downloads – Software downloaded from untrustworthy sources.
- Unpatched software vulnerabilities – Exploits that take advantage of known security flaws.
- Compromised credentials – Attackers using stolen usernames and passwords to gain access.
- Remote Desktop Protocol (RDP) attacks – Exploiting poorly secured remote access tools.
Prevention: How to Protect Your Business
The best defence against ransomware is a layered prevention strategy:
- Keep all software, operating systems, and firmware up to date.
- Train staff to recognise phishing emails and suspicious links.
- Use business-grade antivirus and anti-malware software.
- Enable multi-factor authentication on all accounts.
- Restrict user permissions — employees should only access what they need.
- Regularly back up data to an offline or isolated location.
- Segment your network to limit how far an infection can spread.
The Critical Role of Backups
Regular, verified backups are your most important defence against ransomware. If you have a recent, clean backup stored in a location that was not affected by the attack, you can restore your systems without paying the ransom. Follow the 3-2-1 rule: keep three copies of your data, on two different media types, with one copy stored offsite or in the cloud.
What to Do If You're Attacked
If you suspect a ransomware infection:
- Disconnect the affected device from the network immediately to prevent spread.
- Do not turn off the device — forensic data may be needed.
- Contact your IT support provider as soon as possible.
- Report the incident to the UK National Cyber Security Centre (NCSC) at report.ncsc.gov.uk.
- Do not pay the ransom — payment does not guarantee recovery and encourages further attacks.
- Restore from a clean backup once the infection is contained.
Have an Incident Response Plan
Every business should have a written plan for how to respond to a cyberattack. This plan should include who to contact, what steps to take, and how to communicate with staff and customers. Having a plan ready before an incident means you respond quickly and confidently rather than in panic.