What Is Ransomware? Types, Real Attacks & How to Prevent It

Ransomware is malicious software that encrypts a victim’s files or locks their device and demands a cryptocurrency payment to restore access. It spreads mainly through phishing emails and unpatched software. Victims who lack clean backups face paying the ransom or losing their data permanently. It is one of the costliest forms of cybercrime today.

Ransomware is a type of malicious software that encrypts a victim’s files or locks their device, then demands a payment, usually in cryptocurrency, to restore access. It is one of the most financially damaging forms of cybercrime operating today. According to Cybersecurity Ventures, global ransomware damage costs are projected to reach $265 billion annually by 2031, up from roughly $20 billion in 2021.

• Ransomware encrypts your data and holds it hostage until you pay or recover from backups.
• Phishing emails are the number one delivery method, responsible for over 40% of infections according to Verizon’s 2024 Data Breach Investigations Report.
• Paying the ransom does not guarantee recovery and funds future attacks.
• Double extortion is now the dominant tactic: attackers steal data before encrypting it, then threaten to publish it publicly.
• Incident response skills are in surge demand across Indian SOC teams following attacks on AIIMS Delhi, ONGC and other high-profile targets.

How a Ransomware Attack Actually Works

A ransomware attack in simple words: an attacker gets malware onto your system, the malware encrypts your files so you cannot open them, and then a ransom note appears demanding payment, typically in Bitcoin or Monero, in exchange for a decryption key. The whole process from initial infection to ransom note can take minutes.

The attack lifecycle usually follows a predictable chain. The attacker gains initial access, moves laterally through the network to find high-value targets like file servers and backups, deploys the ransomware payload, and then triggers encryption. Modern ransomware groups wait days or even weeks after initial compromise before pulling the trigger, making detection considerably harder.

How Ransomware Spreads

The most common delivery method is phishing emails containing malicious attachments or links. Verizon’s 2024 DBIR confirmed phishing as the leading initial access vector across ransomware incidents globally. Other common entry points include exposed Remote Desktop Protocol (RDP) ports, unpatched software vulnerabilities, and malicious downloads from compromised websites.

Once inside one machine, ransomware spreads using legitimate Windows tools like PsExec and WMI to move across the network. That is what made WannaCry so catastrophic in 2017: it used the EternalBlue exploit to spread automatically across unpatched Windows systems without any user interaction at all.

Ransomware vs Other Malware

Most malware tries to stay hidden. Ransomware is the opposite: it wants you to know it is there. Where a banking trojan quietly steals credentials over months, ransomware announces itself immediately and creates a ticking clock. That urgency is by design. Panicked victims are more likely to pay quickly without thinking through their options.

The financial motive also separates ransomware from destructive malware like wipers. Wipers, such as the ones used in attacks on Ukrainian infrastructure, aim to destroy data permanently with no recovery path. Ransomware groups, in contrast, need to maintain a reputation for actually decrypting files after payment, otherwise no one would ever pay.

Types of Ransomware You Need to Know

Ransomware is not one thing. It is a category of attack with several distinct variants, each with different targets, tactics and business models.

Crypto Ransomware

This is the most common type. It encrypts files using strong asymmetric encryption, typically RSA or AES, making decryption impossible without the attacker’s private key. LockBit, BlackCat (ALPHV) and Cl0p all fall into this category. Recovery without the key requires either paying the ransom or restoring from clean backups.

Locker Ransomware

Instead of encrypting files, locker ransomware locks you out of your device entirely. The underlying data is often untouched, but the operating system is inaccessible. This variant is more common on mobile devices and is generally easier to remove than crypto ransomware.

Ransomware-as-a-Service (RaaS)

This is where ransomware became an industry. Ransomware-as-a-service works like a criminal franchise: a developer builds and maintains the ransomware platform, then rents it to affiliates who carry out the actual attacks. The developer takes a cut of every ransom paid, often 20-30%. LockBit operated this model until its infrastructure was disrupted by law enforcement in February 2024.

Double and Triple Extortion

Double extortion means attackers steal your data before encrypting it. If you refuse to pay, they threaten to publish sensitive customer records, financial data or intellectual property on a public leak site. Triple extortion adds a third layer: contacting your customers or partners directly to apply additional pressure. The Cl0p group used triple extortion effectively during the MOVEit transfer campaign in 2023, affecting over 2,000 organisations worldwide.

Ransomware Types Compared

Type	What It Does	Recovery Difficulty	Example Groups
Crypto Ransomware	Encrypts files with RSA/AES; data inaccessible without decryption key	High – requires key or clean backup	LockBit, BlackCat, Cl0p
Locker Ransomware	Locks device OS; files usually untouched	Medium – OS restore often sufficient	Android Locker variants
Ransomware-as-a-Service	Developer rents platform to affiliates who run attacks	High – professional-grade tooling	LockBit, REvil, DarkSide
Double Extortion	Encrypts AND exfiltrates data; threatens public leak	Very High – payment pressure doubled	Cl0p, BlackCat, Maze
Triple Extortion	Adds direct contact with victims’ customers or partners	Very High – reputational damage amplified	Cl0p (MOVEit 2023)

Famous Ransomware Attack Examples

Attack / Group	Year	Impact	Entry Method
WannaCry	2017	200,000+ systems in 150 countries; est. $4 billion in damages	EternalBlue SMB exploit
NotPetya	2017	$10 billion in damages; Maersk, Merck, FedEx hit	Compromised software update
Colonial Pipeline	2021	Fuel shortages across US East Coast; $4.4M ransom paid	Compromised VPN credentials
AIIMS Delhi	2022	Patient data of ~40 million exposed; 15+ servers encrypted	Phishing / unpatched systems
MOVEit / Cl0p	2023	2,000+ organisations; BBC, British Airways, Shell affected	SQL injection zero-day

The AIIMS Delhi attack in November 2022 is the most significant ransomware incident in Indian healthcare history. Five servers were encrypted, outpatient and inpatient digital services went offline for nearly two weeks, and manual processes had to be reinstated across one of India’s busiest hospitals. It exposed serious gaps in India’s critical infrastructure security posture. CERT-In subsequently issued a ransomware advisory in 2023 directing Indian organisations to report incidents within six hours and mandating minimum backup and patching standards.

WannaCry remains the single biggest ransomware attack by geographic spread, affecting the UK’s National Health Service, Telefonica in Spain, and thousands of organisations across India in a single day. The patch that would have stopped it had been available for two months before the attack hit.

Ransomware Prevention: What Actually Works

Prevention is cheaper than recovery by a significant margin. IBM’s Cost of a Data Breach Report 2024 found the average cost of a ransomware attack reached $5.13 million, not counting any ransom payment. That figure includes detection, containment, recovery, legal costs and reputational damage. A solid prevention stack costs a fraction of that.

If you are working in a SOC or incident response role, understanding how to stop ransomware before it deploys is one of the most valued skills in the market right now. Indian organisations have significantly increased hiring for incident responders since the AIIMS breach, and the demand has not slowed. If you want to build those skills formally, 3.0 University’s SOC Analyst certification course covers ransomware response, threat hunting and live incident simulations.

The Ransomware Prevention Checklist

1. Patch everything, fast. WannaCry and MOVEit both exploited known vulnerabilities with available patches. Prioritise critical patches within 24-72 hours of release.
2. Back up using the 3-2-1 rule. Three copies of data, on two different media types, with one copy stored offline or air-gapped. Test your restores regularly.
3. Deploy Endpoint Detection and Response (EDR). Endpoint security tools with behavioural analysis can catch ransomware activity before encryption starts.
4. Enforce multi-factor authentication (MFA) on every remote access point, VPN, email and admin console. The Colonial Pipeline attack used a single compromised VPN password with no MFA.
5. Segment your network. Flat networks let ransomware spread everywhere. Segmentation limits the blast radius when something gets through.
6. Train staff to spot phishing. Regular simulated phishing campaigns reduce click rates significantly. Verizon’s data shows human error is involved in the majority of successful breaches.
7. Disable or restrict RDP. Exposed RDP is a favourite entry point. If you need it, put it behind a VPN and enforce MFA.
8. Implement least-privilege access. Accounts should only have the permissions they need. A ransomware payload running under a limited account causes far less damage than one running as a domain admin.

Should You Pay the Ransom?

Most security professionals and law enforcement agencies, including Interpol and India’s CERT-In, advise against paying. Paying funds criminal operations, marks you as a willing target for future attacks, and does not guarantee you will get your data back. Coveware’s Q4 2023 report found that even among victims who paid, roughly 25% still did not receive a working decryptor.

That said, the calculus gets complicated when critical systems are down, lives are at risk, or no backups exist. Colonial Pipeline paid $4.4 million because fuel distribution across the eastern US was at stake. The FBI later recovered roughly $2.3 million of that payment, but that outcome is rare.

The honest answer: if you have clean backups and a tested recovery plan, you will almost never need to consider paying. The decision only becomes genuinely hard when prevention and backup strategy have already failed.

Ransomware Removal Steps

If you are already infected, the priority is containment: isolate infected machines from the network immediately, identify the ransomware variant using tools like ID Ransomware (nomoreransom.org), and check whether a free decryptor exists. The No More Ransom project, supported by Europol and multiple security vendors, has helped victims decrypt files from over 150 ransomware families without paying.

If no decryptor is available and backups are compromised, you are looking at a full rebuild from the last known clean state. That is why offline, tested backups are non-negotiable, not a nice-to-have.

Frequently Asked Questions

What is a ransomware attack in simple words?

A ransomware attack is when malicious software locks or encrypts your files and the attacker demands payment to give you access back. Think of it as a digital kidnapping of your data. The attacker holds your files hostage until you pay, usually in cryptocurrency, or until you restore your systems from backups.

How does ransomware spread?

Ransomware most commonly spreads through phishing emails with malicious attachments or links. It also spreads through exposed Remote Desktop Protocol ports, unpatched software vulnerabilities, drive-by downloads from compromised websites, and infected USB drives. Once inside a network, it uses built-in Windows tools to move laterally and infect as many systems as possible before triggering encryption.

Should you pay ransomware?

Most security agencies and experts say no. Paying does not guarantee recovery, funds criminal operations, and can make you a repeat target. About 25% of victims who paid in Q4 2023 still did not get working decryptors, according to Coveware. The better path is restoring from clean, tested backups. Only consider payment as a last resort when critical infrastructure is at stake and no other option exists.

How can companies prevent ransomware?

Companies should maintain offline backups tested regularly, patch vulnerabilities quickly, deploy EDR software on all endpoints, enforce MFA on every remote access point, segment networks to limit spread, train staff to recognise phishing, and apply least-privilege access controls. No single measure is enough on its own. A layered defence strategy, sometimes called defence-in-depth, is what actually reduces risk to manageable levels.

What was the biggest ransomware attack?

By geographic scale, WannaCry in May 2017 infected over 200,000 systems across 150 countries in a single day and caused an estimated $4 billion in damages. By financial cost, NotPetya (also 2017) caused roughly $10 billion in damage globally, though it functioned more as a destructive wiper than a traditional ransom operation. The 2023 MOVEit campaign affected the largest number of individual organisations.

What is ransomware protection and how do I get it?

Ransomware protection is a combination of technical and procedural controls that reduce the risk of infection and limit damage if an attack occurs. Core components include endpoint detection and response (EDR) software, offline backups, MFA, network segmentation, and regular staff phishing training. For Indian organisations, CERT-In’s 2023 guidelines provide a baseline framework for ransomware readiness.

Ransomware is not going away. The criminal ecosystem around it, particularly the RaaS model, has made it accessible to attackers with minimal technical skill. Your best defence is a combination of good backups, patched systems, trained staff and endpoint monitoring. Get one of those wrong and the others have to work much harder.

If you are building a career in cybersecurity or already work in IT security and want to handle ransomware incidents professionally, 3.0 University’s SOC Analyst certification course gives you the hands-on skills that Indian and global employers are actively hiring for right now.

Last updated: July 2026. Reviewed by the 3University editorial team.