Ransomware Explained: How to Protect Your Systems and Secure Your Data

Ransomware is one of the most dangerous cybersecurity threats today. It can lock your files, disrupt your operations, and cost millions. Whether you’re a business owner, IT administrator, or everyday computer user, understanding ransomware is essential.

This guide explains what ransomware is, how it works, how to defend against it, and why having solid backups and an incident response plan can make the difference between recovery and disaster.

What Is Ransomware? #

Ransomware is malicious software designed to block access to a computer system or files until a ransom is paid. It usually works by encrypting data, making it unreadable without a decryption key that the attacker offers if you pay.

In recent years, ransomware has become more aggressive and profitable. Attackers now often use a double extortion tactic: they steal your data before encrypting it and threaten to publish it if you don't pay.

How Ransomware Works #

A ransomware attack usually follows these steps:

  1. Entry
    The attacker gains access to the system. This is done through a vulnerability, phishing email, infected attachment, or exposed service.
  2. Execution
    The ransomware installs and runs on the system. It starts encrypting files on local drives, shared folders, and backups it can reach.
  3. Notification
    A ransom note appears. It demands payment, typically in cryptocurrency, and may include a timer or threat of public data release.
  4. Outcome
    If the victim pays, they may or may not receive a decryption key. If they don’t pay, they lose access to their data unless backups are intact and unaffected.

What Is an Attack Vector? #

Understanding attack vectors helps you close the doors attackers use to get in.

An attack vector is the path or method used by attackers to deliver ransomware. Common vectors include:

  • Phishing emails with malicious links or attachments
  • Compromised remote access tools like SSH
  • Software vulnerabilities that haven’t been patched
  • Malicious downloads or fake software updates
  • Compromised supply chains (e.g. infected updates or third-party tools)

Platform Vulnerabilities #

Ransomware can target any system, including Android, iOS, Linux, macOS, or Windows. The attack methods vary by platform. Here's a breakdown of the risk levels and common attack methods for each platform:

Platform Risk Level Common Attack Methods
Android Medium Malicious apps
iOS Low (unless jailbroken) Credential theft
Linux Medium SSH attacks, CMS flaws
macOS Medium Trojanised apps
Windows High Phishing, RDP, malware

In addition, cloud environments and network storage devices can also be affected by ransomware if they are not adequately secured. Proper protection measures, such as strong access controls and encryption, are essential to safeguard these assets.

Most Successful Ransomware Attacks #

These are some of the most impactful ransomware attacks in history, highlighting the severity and wide-reaching consequences of such attacks:

1. City of Atlanta (2018)

  • Attack: SamSam ransomware crippled the city’s internal systems, including critical services such as police, court systems, and utilities.
  • Impact: The city’s recovery cost exceeded $17 million, including efforts to restore systems and improve security measures.

2. Colonial Pipeline (2021)

  • Attack: A ransomware attack targeted Colonial Pipeline, one of the largest fuel pipelines in the US, shutting down operations for several days.
  • Impact: The company paid over $4 million in ransom. The attack led to significant fuel shortages and increased fuel prices across the East Coast.

3. Kaseya (2021)

  • Attack: The REvil ransomware group exploited vulnerabilities in Kaseya’s IT management software, affecting over 1,500 companies globally.
  • Impact: The attack disrupted operations for many businesses and forced Kaseya to shut down its SaaS systems to prevent further damage.

4. NotPetya (2017)

  • Attack: Originally masquerading as ransomware, NotPetya used a destructive payload that wiped data from infected systems instead of encrypting it.
  • Impact: Major companies like Maersk, Merck, and pharmaceutical firms were affected, leading to billions of dollars in damages. The attack caused significant disruptions to global shipping and healthcare operations.

5. WannaCry (2017)

  • Attack: WannaCry exploited a vulnerability in Microsoft’s SMBv1 protocol, affecting over 200,000 systems across 150 countries.
  • Impact: The attack disrupted organisations globally, including the UK’s National Health Service (NHS), delaying surgeries and critical care.

These attacks serve as stark reminders of the devastating potential of ransomware. The costs are not just financial but also operational, affecting reputation, trust, and long-term recovery efforts.

The Importance of Backups #

Backups are your last line of defence in a ransomware attack. If ransomware encrypts your systems, a reliable backup can be the difference between recovery and total data loss. However, not all backups are effective. To be truly protective, backups must be secure, isolated from the main environment, and regularly tested.

How Ransomware Targets Backups #

Modern ransomware is designed to locate and destroy backups. It scans for connected drives, accessible network shares, cloud-mounted storage, and any system with write access. If your backups are online or poorly protected, they are likely to be encrypted or deleted along with your primary data.

How to Protect Your Backups #

To make your backups resilient to ransomware:

  • Implement Immutable Backups
    Use write-once, read-many (WORM) storage or backup platforms with immutability features to prevent tampering or modification by ransomware.
  • Use Offline or Air-Gapped Backups
    Store backups on media not connected to your network when not in use, ensuring they are isolated from ransomware attacks.
  • Isolate Backup Systems
    Restrict network access to backup systems and apply strict firewall rules to limit exposure and prevent ransomware from reaching your backups.
  • Encrypt Backup Data
    Encrypt backups to protect them from exposure or theft in case storage media is compromised.
  • Require Multi-Factor Authentication (MFA)
    Apply MFA for all backup management and administration functions to ensure that only authorised users can access and modify backups.
  • Monitor Backup Systems Continuously
    Set up alerts to monitor backup activity, and immediately notify you of any unexpected deletions, modifications, or suspicious activities.
  • Regularly Test Backup Restores
    Conduct regular restore tests to ensure that your backups are complete, recent, and functional. This ensures you can recover data when needed.

A backup that cannot be restored is as useless as no backup at all. Protecting and verifying your backups should be a non-negotiable part of your ransomware defence strategy.

Incident Response Plan #

A well-defined incident response plan is crucial to quickly contain and recover from a ransomware attack. The goal is to minimise damage, preserve evidence, and restore normal operations with minimal downtime. Your plan should be comprehensive and include the following stages:

  1. Preparation
    • Define Roles and Responsibilities
      Clearly assign roles for the incident response team, including leadership, IT, legal, and communication experts.
    • Establish Communication Procedures
      Develop internal and external communication protocols. Ensure that all stakeholders (e.g., employees, customers, regulators) are informed promptly and correctly.
    • Document Assets and Critical Systems
      Maintain an up-to-date inventory of all key assets, data, and systems, including critical infrastructure and backup systems.
    • Simulate Attack Scenarios
      Conduct regular drills to test your response to simulated ransomware attacks, improving readiness and coordination.
  2. Detection and Analysis
    • Monitor Systems with EDR or SIEM Tools
      Use endpoint detection and response (EDR) or security information and event management (SIEM) tools to monitor systems for signs of an attack.
    • Correlate Logs and Alerts
      Review and analyse logs to detect abnormal activities and correlate alerts across systems to identify potential entry points.
    • Identify Attack Scope and Entry Point
      Determine the extent of the attack and how the ransomware infiltrated your network, allowing you to focus on containment.
  3. Containment
    • Isolate Affected Systems Immediately
      Quickly disconnect or isolate infected machines from the network to prevent further spread of the ransomware.
    • Disable Lateral Movement
      Block access to administrative tools and shared drives to stop the ransomware from spreading to other systems.
    • Preserve Logs and Evidence for Forensics
      Retain logs and system data to support forensic analysis, helping you understand the attack’s origin and impact.
  4. Eradication and Recovery
    • Remove Ransomware and Reset Credentials
      Clean the systems by removing the ransomware and resetting passwords for affected accounts to prevent further exploitation.
    • Restore from Secure, Clean Backups
      Ensure recovery from offline or air-gapped backups that are not compromised. Verify backup integrity before restoration.
    • Rebuild Affected Systems and Verify Integrity
      Rebuild the systems from scratch if necessary, and thoroughly verify that they are free from malware before reconnecting them to the network.
  5. Post-Incident Review
    • Analyse Root Cause
      Identify the root cause of the attack to understand how it bypassed existing defences.
    • Update Policies and Defences
      Review and update security policies, procedures, and defences to prevent future attacks. Implement lessons learned.
    • Report to Regulators if Required
      Comply with regulatory requirements for breach notifications, particularly if sensitive data was exposed.

Ongoing Testing and Improvement

Regularly test your incident response plan through tabletop exercises or live drills. This ensures that everyone is familiar with their roles and that your response is efficient and effective in a real-world scenario.

A well-practiced and updated incident response plan is essential for reducing the impact of ransomware and ensuring a rapid recovery.

Best Security Practices #

Ransomware protection requires a comprehensive, multi-layered approach. It’s not about relying on a single tool, but rather implementing a continuous, proactive strategy across your entire infrastructure.

  1. Keep Systems Updated with the Latest Security Patches
    Ensure all operating systems, applications, and software are regularly updated with the latest security patches. Unpatched vulnerabilities are one of the primary attack vectors for ransomware.
  2. Enforce Strong, Unique Passwords and Multi-Factor Authentication (MFA) Everywhere
    Implement strong, complex passwords for all accounts and require MFA for all critical systems. This significantly reduces the chances of attackers gaining access through stolen or weak credentials.
  3. Limit Admin Rights and Apply the Principle of Least Privilege
    Restrict administrative rights and ensure users only have access to the resources necessary for their roles. This limits the potential damage an attacker can do if they gain access to an account.
  4. Use Advanced Threat Protection Tools (EDR, Firewalls, DNS Filtering)
    Deploy endpoint detection and response (EDR) tools, firewalls, and DNS filtering solutions to actively monitor systems for any signs of malicious activity, helping to stop ransomware early.
  5. Segment Your Network to Limit Spread
    Segment your network into isolated zones to prevent ransomware from spreading throughout your entire infrastructure. This limits the scope of the attack and makes containment easier.
  6. Monitor Logs and System Activity for Early Detection
    Continuously monitor system logs and network activity to identify unusual patterns or suspicious behaviour. Early detection can help prevent an attack from escalating.
  7. Disable Unnecessary Services and Remote Access
    Disable any unnecessary services, ports, or remote access tools (such as RDP) that aren’t essential. If remote access is required, ensure it is secured with strong authentication and VPNs.
  8. Train Users to Spot Phishing and Report Suspicious Activity
    Educate employees on how to recognise phishing attempts and other social engineering attacks. The human element is often the weakest link, so regular training is vital to reduce the risk of successful attacks.

By prioritising these security practices, you significantly reduce your exposure to ransomware attacks and improve your ability to detect, respond to, and recover from incidents effectively.

Frequently Asked Questions #

Q: Should I pay the ransom?
A: No, unless you’ve exhausted all other options. Paying encourages further attacks and doesn’t guarantee you’ll get your data back.

Q: Can antivirus stop ransomware?
A: Sometimes, but not always. Modern ransomware may bypass signature-based antivirus. Use behaviour-based tools like EDR or XDR.

Q: Can ransomware infect cloud storage?
A: Yes, especially if cloud storage is mounted like a local drive. Encrypting files locally can also sync encrypted versions to the cloud.

Q: How long does it take to recover?
A: Without backups, recovery can take weeks or months. With strong backups and a response plan, recovery can begin immediately.

Q: What is double extortion?
A: When attackers first steal your data, then encrypt it. They demand payment not only for decryption but also to prevent data leaks.

Q: Is Linux safer from ransomware?
A: Linux is less targeted, but not immune. Increasing attacks on servers and web-facing Linux systems prove it is a growing target.

Next Steps #

Ransomware continues to be a significant and growing threat, impacting organisations of all sizes, across all platforms and sectors. To defend against it effectively, a comprehensive strategy is required that combines the following key elements:

  1. Preventive Security
    This includes regular patching of systems, user training, and enforcing strict access controls. By addressing vulnerabilities proactively, you reduce the risk of ransomware gaining a foothold in your environment.
  2. Real-Time Detection
    Implement endpoint detection and response (EDR) tools, continuous monitoring, and alerting systems. These help detect ransomware early, allowing for quick containment and minimising the impact of an attack.
  3. Strong, Tested Backup Systems
    Maintain secure, offline, or air-gapped backups that are regularly tested. These backups should be isolated from the main network to ensure they remain intact in the event of an attack, enabling you to restore your systems without paying a ransom.
  4. A Well-Practised Incident Response Plan
    Having an effective incident response plan is crucial. Ensure your plan includes clear roles, responsibilities, and procedures for detection, containment, eradication, and recovery. Regularly test the plan to keep your team prepared for any ransomware attack.

Prevention is Cheaper Than Recovery

The costs of recovering from a ransomware attack far outweigh the investment required for preventive measures. Act now. Audit your systems, strengthen your defences, and, most importantly, develop a reliable backup and response strategy. By taking proactive steps today, you ensure that you're prepared when it matters most.