Ransomware & Incident Response·Updated 2026-10-21

What is ransomware and how does it get in?

Short answer

Ransomware is malware that encrypts or steals an organization’s data and demands payment to restore or not publish it. It usually gets in through phishing, stolen passwords for remote access, or unpatched internet-facing systems, and attackers often spend days inside before launching it.

The details

Many groups now steal data before encrypting it, so backups alone do not remove the threat of a leak. Prevention focuses on MFA for remote access, fast patching of internet-facing systems, least privilege and good backups.

Useful next reads and tools

How I Investigate a Suspicious PowerShell Alert in a SOC Lab · guide

Terms explained

Ransomware: Ransomware is malware that encrypts or steals data and demands payment to restore access or prevent publication.
Least privilege: Least privilege means giving each user, service or AI agent only the access it needs to do its job, and no more, for only as long as it needs it.
Malware: Malware is any software designed to harm, spy on or gain unauthorized control of a device, network or account.
Multi-factor authentication: Multi-factor authentication (MFA) requires two or more kinds of proof to sign in, such as a password plus an app prompt, security key or biometric unlock of a passkey.
Patch management: Patch management is the process of finding, prioritizing, testing and installing software updates that fix security flaws.
Phishing: Phishing is a fraudulent message, usually email, that impersonates a trusted sender to trick people into revealing credentials, paying money or running malware.

Sources

CISA #StopRansomware