---
title: "What Is Ransomware? Attacks & Defenses | Bytes Unlimited"
description: "Ransomware encrypts your data and demands payment to get it back. Understand the modern attack chain — initial access, lateral movement, exfiltration, encryption — and the layered defenses that stop it."
canonical: https://www.bytesunlimited.com/glossary/ransomware/
---

 GLOSSARY · Security 

#  Ransomware 

 Malware that encrypts a victim's files (and increasingly, exfiltrates them) then demands payment for decryption keys and non-disclosure. The financially defining cyber threat to small and medium business since 2017\. 

## Detailed definition

**Ransomware** evolved from a nuisance into the dominant existential threat to small businesses over the last decade. The modern variant is rarely just encryption — most ransomware groups now run “double extortion”: they exfiltrate sensitive data _before_ encrypting it, then threaten to publish or sell the data even if the victim restores from backup. The financial damage from a single successful attack routinely runs into hundreds of thousands of dollars even before the ransom itself.

## The modern attack chain

A ransomware deployment is the _end_ of a multi-step intrusion, not the beginning. Understanding the chain is how you defend against it.

1. **Initial access** — usually [phishing](/glossary/phishing/) (stolen credentials) or an unpatched vulnerability on an internet-facing system
2. **Persistence + reconnaissance** — attacker establishes a foothold, looks around, identifies the most valuable systems
3. **Privilege escalation** — using stolen credentials or local vulnerabilities to gain administrator access
4. **Lateral movement** — pivoting through the network to reach backup systems, file servers, databases
5. **Exfiltration** — copying valuable data out for the second extortion layer
6. **Encryption** — only at the very end, often timed for a weekend or holiday to maximize pressure

The encryption itself is the loudest, fastest, most visible step. Everything before it is quieter — and stoppable.

## Layered defense

No single product stops ransomware. The defenders that survive these attacks have layered controls that interrupt the chain at multiple points:

* **[MFA](/glossary/mfa/) everywhere** stops most initial-access attempts at the credential step
* **Aggressive patching** closes the unpatched-vulnerability vector
* **Email security + awareness training** catches the phishing that started it
* **[EDR](/glossary/edr/)** with file-rollback catches the malware before encryption completes
* **Network segmentation** limits lateral movement once an attacker is in
* **Privileged access management** prevents single-credential compromise from becoming full-domain compromise
* **Immutable, tested backups** ensure the encryption step doesn’t cost you the business — provided you’ve also verified offline copies exist that the attacker couldn’t reach

Most clients we onboard have two or three of these layers; few have all of them. The work of an MSP, in practice, is closing those gaps before the chain runs.

HOW WE HELP

## Related Bytes Unlimited services

* [ Bitdefender GravityZone Bitdefender GravityZone Cloud MSP Security — endpoint detection and response for SMB fleets, managed centrally.](/services/bitdefender-gravityzone/)
* [ Security & Compliance PCI DSS, HIPAA, and general security posture work. Endpoint protection, MFA, awareness training, audit-ready documentation.](/services/security/)

RELATED TERMS

## See also

* [ EDR ](/glossary/edr/)
* [ Phishing ](/glossary/phishing/)
* [ RTO/RPO ](/glossary/rto-rpo/)

AUTHORITATIVE SOURCES

## External references

* [ CISA — StopRansomware.gov  (opens in new tab) ](https://www.cisa.gov/stopransomware)

##  Need help applying Ransomware to your business? 

 We've done this kind of work across New York. First conversation is free. 

[ Get In Touch ](/contact/) [ Back to Glossary ](/glossary/)

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