Ransomware is malware that encrypts an organization''s data (and increasingly steals it first) to extort a payment for restoring access and withholding a leak. It is among the most disruptive cyberattacks, but its defining lesson is that the encryption is the last step: the attack almost always begins somewhere cheaper to stop, usually a phishing email or a stolen credential.
Key facts
- Most ransomware intrusions begin with phishing, stolen credentials or exploited vulnerabilities, days or weeks before any file is encrypted.
- Double extortion is now standard: data is stolen before encryption, so backups alone do not remove the leak threat.
- The ransomware-as-a-service model industrialized it, letting non-experts run attacks.
The attack chain
Initial access (phishing, stolen credentials, unpatched systems), then reconnaissance and lateral movement, privilege escalation, data theft, and finally encryption and the ransom demand. The long middle is the point: defenders have many days to detect and disrupt before encryption, and the earliest, cheapest interception is at initial access, overwhelmingly email. See also zero-day attacks and account takeover for the two other main entry routes.
How to defend
Prioritize the entry points: email security against the phishing that starts most chains, phishing-resistant MFA so stolen credentials are not enough, and fast patching. Then limit blast radius: network segmentation, least privilege, and monitoring for the lateral movement and account-takeover behavior that precede encryption. Finally, resilience: offline, tested backups and a rehearsed incident plan, because the worst case must be survivable without paying.
How Sentaro helps
Sentaro guards the most common front door: the phishing and credential-theft emails that begin most ransomware intrusions, and the account-takeover behavior that follows. Stopping the initial-access email is the cheapest possible place to break the chain, weeks before encryption would occur.