A complete guide to ransomware attacks

What is a ransomware attack?

Ransomware is a type of malicious software that blocks access to a computer system or encrypts valuable data until a ransom is paid. It spreads through the network via phishing emails, malicious downloads, and exploitation of unpatched vulnerabilities. Once activated, it locks files or systems and demands payment (mostly in cryptocurrency) to unblock access.

Ransomware is one of the most damaging forms of malware that threatens organizations of all sizes because it directly impacts business continuity, disrupts operations, and causes both financial and reputational harm.

Ransomware variants

Ransomware comes in several forms and types, each using different tactics to pressure victims into paying. These are:

• Encrypting ransomware (crypto): Encrypts files and demands payment for the decryption key.
• Locker ransomware: Denies access to the entire system, locking out users completely.
• Leakware/doxware: Threatens to publish sensitive data if a ransom is not paid.
• Scareware: Displays fake warnings or security alerts to trick users into paying.
• Wipers: Permanently destroys data instead of demanding ransom, causing irreversible loss.

Ransomware has evolved dramatically, from the AIDS Trojan in 1989 (which spread via floppy disks) to WannaCry in 2017 (which crippled global systems using a wormable exploit). By 2025, attackers have adopted triple extortion, which combines data encryption, data leaks, and direct threats to the victims’ customers and partners. This makes modern ransomware more aggressive and far-reaching than ever before.

How does ransomware work?

Ransomware attacks follow a structured lifecycle: infiltrate, encrypt, and extort. By understanding each stage in how ransomware works, organizations can recognize warning signs early and respond before widespread damage occurs.

Step 1: Infection

The attack begins with an initial compromise. Common entry points include:

• Phishing emails with malicious attachments or links
• Drive-by downloads from compromised websites
• Exploitation of internet-facing services such as Remote Desktop Protocol (RDP)
• Abuse of stolen or weak credentials
• Unpatched vulnerabilities in software, VPNs, or third-party services
• Deployment of precursor malware/commodity loaders, such as Emotet, QakBot, Bumblebee
• Compromising managed service providers (MSPs) and supply-chain partners to distribute ransomware widely

Once inside, the malware establishes a foothold in the target environment and proceeds with lateral movement and escalation.

Step 2: Execution

After infiltration, the ransomware executes its payload. It starts by scanning local and network drives for valuable files, deleting shadow copies and backups to prevent recovery, and sometimes stealing credentials for privilege escalation. Some variants use built-in tools like PowerShell or Windows Management Instrumentation (WMI) for stealthy execution. Modern ransomware can also deploy additional tools or scripts to disable security defenses, such as antivirus and other security tools, before proceeding further.

Step 3: Encryption and extortion

This phase of the attack answers the question, what does ransomware do to the files it gets control of? In this phase, the malware uses hybrid encryption to lock critical files and systems. Hybrid encryption combines fast symmetric encryption to secure the data with strong asymmetric encryption to protect the keys, which are controlled by the attackers using a private key. Before or during encryption, attackers steal sensitive data to strengthen their leverage. They then demand payment in exchange for the decryption key needed to unlock the files. Over time, tactics have evolved from single extortion (file encryption) to double extortion (encryption + data theft) and now triple extortion, which adds pressure through threats such as targeting the victim’s customers and partners or launching distributed denial-of-service (DDoS) attacks.

Step 4: Ransom demand

Once encryption is complete, a ransom note appears on infected systems with payment instructions and deadlines. Attackers mostly demand payment in cryptocurrencies such as Bitcoin or Monero for anonymity. To hide their identity and location, they route communication through Tor-based portals. These portals are also used to host ransom payment sites or "leak sites" and provide decryption instructions after payment.

Step 5: Expansion

In advanced attacks, ransomware spreads laterally across the network using stolen credentials and by exploiting domain trust relationships. Attackers then compromise additional endpoints to expand control and encrypt more systems. They may also target or encrypt backups, cloud environments, and connected supply chains to maximize damage and reduce recovery options. These tactics increase an attacker’s bargaining power during ransom negotiations.

Step 6: Outcome

After the attack is complete, the victim either pays (with no guarantee of data recovery) or refuses to pay, opting for recovery through backups, decryptors, and law-enforcement or incident-response support. Each path carries costs, risks, and follow-on actions.

Attack flow diagram

The following diagram and an example-story show the progression of a ransomware campaign from the attacker’s initial intrusion through the eventual business outcomes.

In a financial services company, a ransomware attack began when an employee opened a phishing email that installed malware and gave attackers network access. Soon after, critical files were encrypted, and sensitive data was exfiltrated to attacker servers.

Ransom notes were displayed on affected systems, demanding payment and threatening to leak stolen data. The IT team contained the attack, restored systems from offline backups, and involved law enforcement.

Instead of paying the ransom, the organization rebuilt affected systems and strengthened defenses with better backups, MFA, and staff training.

Examples of ransomware attacks

Here are high-profile, real-world examples of major ransomware incidents that demonstrate different tactics, impacts, and motivations.

Consequences of ransomware attacks

Ransomware attacks have far-reaching consequences that go beyond data encryption and ransom payments. Their effect on an organization’s finances, operations, reputation, and legal standing can create long-term challenges.

Common targets of ransomware attacks: Who is at risk?

Let’s be candid, any organization that relies on digital systems to store data or deliver services can succumb to a ransomware attack. However, certain industries face higher risks due to the value of their data, the critical nature of their operations, or their limited cybersecurity resources. Here are some of the most common targets of ransomware attacks.

Risk assessment

To understand the risk level of ransomware attacks, you need to evaluate their potential impact, ease of execution, and overall likelihood. Here is a discussion of each risk factor and its justification.

How to prevent ransomware attacks

To prevent ransomware attacks, companies should implement a defense strategy that combines strong technical controls, employee awareness, and proactive planning. No single tool can stop an attack, but organizations can greatly reduce their risk exposure by addressing vulnerabilities across systems, credentials, and human behavior.

Internet-facing systems

Attackers have been observed to exploit exposed services and unpatched systems to gain initial access. Organizations should:

• Apply regular patches and updates to operating systems, web applications, and firmware to close known vulnerabilities.
• Disable outdated protocols such as SMBv1, which are abused in ransomware propagation.
• Conduct routine vulnerability scans and penetration tests to identify weak points.
• Limit public access to remote management ports (such as RDP, SSH) and use VPNs or secure gateways for remote connections.

Credentials

Compromised credentials serve as an easy entry point for ransomware operators. Organizations should:

• Enforce phishing-resistant MFA, especially for privileged and remote accounts.
• Adopt identity and access management (IAM) controls to manage user permissions and automate provisioning/deprovisioning.
• Use password managers to generate and store strong, unique passwords.
• Admins should use a regular account for daily tasks and only switch to their admin accounts when they actually need administrator privileges, to limit the risk of lateral movement.

Phishing and social engineering

Phishing is the most widely used ransomware delivery method. To build your defenses:

• Train employees to recognize phishing emails, fake login pages, and suspicious attachments.
• Implement email authentication standards such as DMARC, SPF, and DKIM to block spoofed domains.
• Filter email attachments and links using sandboxing and advanced threat protection tools.
• Conduct simulated phishing exercises to test and reinforce awareness.

Endpoint protection

Endpoints are prime targets for ransomware payloads. To protect them:

• Deploy endpoint detection and response (EDR) tools to monitor behavior and block malicious activity in real time.
• Implement application whitelisting and blacklisting to prevent unauthorized executables from running.
• Use intrusion detection systems (IDS) and Sysmon configurations to log and analyze suspicious system events.
• Centrally manage and regularly update all endpoint agents.

Backups

You must devise a robust strategy to back up your systems and data. This will help you recover quickly from an attack and minimize damage. Because attackers attempt to delete backups, you should make sure backups are stored securely.

• Maintain offline or immutable backups that cannot be altered or deleted by attackers.
• Create golden images of critical systems so that they can be restored quickly.
• Use cloud-to-cloud backup solutions for SaaS and cloud workloads.
• Secure the systems where your backups reside using identity and access management (IAM) systems such as MFA and firewalls.
• Test backup restore processes regularly to ensure that they work when needed.

General hardening

Strengthen your overall security posture to reduce the attack surface.

• Adopt a zero trust architecture, where every user and device must be verified regardless of location.
• Segment networks to contain potential ransomware spread between departments or systems.
• Maintain an asset inventory to track all devices, software, and services connected to your environment.
• Limit administrative privileges and enforce the principle of least privilege across all accounts.

Precursor malware and endpoint protection

Many ransomware attacks are preceded by other malware, such as TrickBot, Emotet, or QakBot, which prepare systems for ransomware deployment. Organizations should:

• Use centrally managed antivirus and EDR solutions with heuristic and behavioral detection.
• Implement application whitelisting and blacklisting to block unapproved scripts and executables.
• Monitor with intrusion detection systems (IDS) and Sysmon configurations for early warning signs.
• Act quickly to remove malware at an early stage and isolate affected systems to stop the attack from spreading.

Third parties and managed service providers (MSPs)

Attackers like to target trusted vendors and MSPs to reach multiple clients at once.

• Draw contracts that clearly state security obligations for any third party that handles your data or infrastructure.
• Apply least-privilege access for vendors to limit network visibility for them.
• Require secure cloud practices (SCPs) such as dedicated accounts, encryption, and multi-tenant isolation in cloud environments.
• Continuously monitor vendor activity and access logs for anomalies.

Preparing for ransomware incidents

Even with the best defenses, organizations must be prepared for ransomware incidents. Your readiness determines how quickly you can recover.

• Develop and test an incident response plan (IRP) that defines roles, escalation paths, and containment procedures.
• Create an internal and external communications plan that should include media and customer notifications.
• Save copies of critical contacts and IRP documents offline. These may include executives, IT staff, law enforcement (such as FBI and CISA), and relevant Information Sharing and Analysis Centers (ISACs).
• Understand the data breach notification requirements under state, federal, and international laws.
• Define the role of cyber insurance and legal counsel to guide ransom decisions and post-incident recovery.

How Netwrix can help

Netwrix offers a suite of security tools that strengthen your defenses and improve incident response against ransomware. While Netwrix Threat Manager serves as the frontline defense, the company’s other solutions also protect against ransomware by strengthening visibility, limiting blast radius, and enabling faster recovery.

Netwrix Threat Manager

Threat Manager delivers real-time threat detection and automated response.

• It continuously monitors both file system and identity-related activities in real time. It detects ransomware-like behaviors (such as mass file operations, suspicious RMM tool usage, unusual writes or deletions, and abnormal encryption patterns) through its advanced threat models. The application also identifies privilege escalation attempts, account anomalies, and suspicious authentications across Active Directory, and integrates seamlessly with Microsoft Entra ID for hybrid environments.
• It triggers automated containment actions, such as disabling compromised accounts, resetting passwords, ending active sessions, and marking accounts as “compromised.”
• It also raises real-time alerts that are delivered via email or mobile notifications.
• It can also be integrated and customized via PowerShell scripts, webhooks, and SIEM/alerting systems (Slack, ServiceNow, Teams).
• Threat Manager extends protections to Microsoft Entra ID in addition to on-prem AD environments.

Netwrix Threat Prevention

Threat Prevention adds a preventive layer by alerting or blocking suspicious changes in Active Directory, risky authentication events, and critical object changes before they escalate into breaches.

Netwrix Endpoint Protector

Endpoint Protector provides endpoint control and prevents data loss. It monitors and controls data transfer by blocking rogue USB and other unauthorized devices, and controlling file transfers. It also enforces encryption and can even work offline, mitigating the risk of data exfiltration.

Netwrix Auditor

Auditor tracks and reports on system changes, user activity, and file modifications. It gives you visibility into who did what and when, which is useful in detecting early signs of ransomware activity and post-incident investigation.

Detection, mitigation and response strategies

Organizations that detect and respond to ransomware attacks quickly can limit damage and recovery time.

Detection

Early detection is important to stop ransomware infection before it spreads. Security teams should continuously monitor systems and networks for warning signs such as:

• Suspicious file activity, including mass file renaming, encryption, or deletion of shadow copies (which are used for system restore).
• Abnormal network traffic, like unexpected spikes in data transfer or communication with known command-and-control (C2) servers.
• Credential dumping attempts using tools like Mimikatz or LSASS access.
• Unusual remote monitoring and management (RMM) tool activity or Cobalt Strike beacons, which may indicate lateral movement or attacker persistence.

EDR, SIEM, and Sysmon solutions enable proactive monitoring, which can help detect these indicators early and trigger alerts for investigation.

Mitigation steps

On detecting a ransomware incident, security teams must act swiftly to contain the threat and preserve evidence. IT, legal, and executive teams must coordinate to ensure an effective and compliant response.

• Isolate infected systems (individual computers, servers, etc.) immediately from the network to prevent further spread.
• If needed, take affected network segments offline to cut them off from communication with uncompromised devices. Do this when you suspect that the compromise has spread across multiple devices within a particular network segment, or when you cannot immediately identify all affected systems.
• After identifying and disconnecting infected devices, use anti-malware tools to remove the ransomware. Avoid resuming normal operations until all systems are clean, as hidden malware can reappear and infect more files.
• Once you are confident that your network is free of ransomware, run a full system scan to uncover any remaining malware that could cause problems after recovery.
• Try to locate the source of the ransomware or malware. This will make it easier to determine how the infection spreads. Ask employees about any unusual behavior they have noticed on their computers or if they have clicked any attachments or links in suspect emails.
• Preserve forensic evidence, including system images, memory dumps, and log files, for later analysis and investigation.
• Notify appropriate authorities, such as the FBI, CISA, or your sector’s Information Sharing and Analysis Center (ISAC).

Response

After containing the threat, the focus shifts to restoring systems and preventing recurrence:

• Reset all passwords and revoke compromised credentials to block attacker access.
• Patch the exploited vulnerabilities and harden systems to close security gaps.
• Perform a clean rebuild of affected machines using golden images (trusted system baselines verified to be malware-free).
• If the backup files have been hacked or deleted, look for potential decryptors. Several organizations provide support with free tools and programs that can help decrypt data, as discussed in the Resources and government support section.
• Share indicators of compromise (IOCs) with the broader community via trusted platforms like StopRansomware.gov or your sector’s ISAC. This can help others defend against similar attacks.

Should you pay the ransom?

The FBI, CISA, and NSA strongly advise organizations not to pay the ransom. Paying carries serious risks.

• There is no guarantee that data will be decrypted or that attackers will not strike again.
• Payments fund criminal operations and encourage further attacks.
• Some ransomware groups are sanctioned entities, meaning payment could violate federal laws and trigger penalties.

Instead of paying, consider safer alternatives such as:

• Restore from secure backups maintained offline or in immutable storage.
• Use free decryptors available from the No More Ransom project.
• Engage law enforcement, who may assist in recovery or in negotiating with the attackers without violating regulations.

The UK government has gone as far as to propose a ban on ransom payments, under which public sector bodies and operators of critical national infrastructure (including the NHS, local councils, and schools) would be prohibited from complying with ransom demands.

Resources and government support

Organizations do not have to face ransomware alone. Many government and industry resources provide assistance, intelligence, and recovery tools.

Industry-specific impact

Ransomware affects every sector differently, but its consequences are universally severe. Each industry faces unique operational, financial, and regulatory risks that can disrupt services, damage reputation, and erode public trust.

How Netwrix Data Classification can help

By classifying and tagging sensitive data (healthcare records, financial information, government data) across on-premises and cloud environments, Netwrix Data Classification enables organizations to redirect protection and backup efforts to what matters most. The solution can also simplify compliance activities. It maps and tags data subject to regulations (HIPAA, GDPR, PCI DSS), making it easier to generate reports, respond to data subject requests, and prove data handling policies.

Attack evolution and future trends

Ransomware attacks are likely to become faster, more adaptive, and more automated. Due to the rising use of AI, expansion into cloud environments, and targeting of critical infrastructure, it will become harder for organizations to detect and contain the attacks. By staying ahead of ransomware trends, organizations can prepare equally strong defenses to encounter the threat.

Key statistics and infographics

Ransomware attack numbers and ransom demands have been rising year after year. The following key statistics and graphs highlight recent trends and financial impacts, offering a data-driven look at why ransomware remains a top concern for organizations in every sector.

• Research shows that phishing is indeed a dominant attack vector. Guardz’s 33 Phishing Attack Statistics in 2024 claims that 9 out of 10 data breaches in 2023 originated from phishing attacks targeting employees.
• StationX states that phishing is the most common method for delivering ransomware, responsible for 45% of all ransomware attacks.
• Ransomware was responsible for over 70% of reported cyber incidents in 2023, as reported by Cyberint. However, Bright Defense mentions that in 2024, ransomware accounted for 32% of reported malware incidents, showing a significant drop.
• Average ransom payments increased significantly in 2024. For example, Sophos reports that the average ransom payment rose from about $400,000 in 2023 to roughly $2 million in 2024 for organizations that paid, indicating a sharp increase from previous years. However, total payments dropped notably in 2024, both in overall value and in the proportion of victims who paid, even as ransom demands remained high.
• Global ransomware damages are projected to cost $265 billion annually by 2031. These estimates are based on widely cited predictions that the price tag will increase 30% every year.
• Healthcare remains the #1 most targeted industry, followed by finance, government, and education. According to the FBI's 2024 Internet Crime Report, healthcare had more cyberthreats last than any other critical infrastructure industry. With 444 reported incidents, 238 were ransomware threats. However, critical manufacturing had more ransomware incidents, with 258.

Pie chart showing common attack vectors

Geographic hotspots of ransomware attacks (US, UK, EU, Australia)

Final thoughts

Let’s get back to what ransomware attacks are. The definition of a ransomware attack does not just represent its criminal implications. It also hints at a battle for control in an age where data defines power.

No organization is immune to the threat, regardless of size or industry. While the statistics are sobering, the good news is that most ransomware attacks are preventable.

The fight against ransomware cannot be won with a single solution, but rather through a combination of technical controls, employee awareness, and a proactive security mindset. In the end, survival will depend not on who avoids the next attack, but on who is prepared to recover from it.