SQL Server Ransomware Attacks: How They Work and How to Harden Your Database

This report explains how exposed or poorly configured Microsoft SQL Server instances enable fast ransomware campaigns: attackers gain initial access (often via exposed port 1433 or brute-force of the sa account), escalate to OS-level execution through features like xp_cmdshell/CLR/OLE Automation or stolen service credentials, then stage lateral movement, delete backups, and encrypt MDF/LDF files—sometimes within minutes. The document highlights observed incidents and honeypot data, describes detection signals (SQL audit events, EDR/process lineage, backup access patterns), and provides a prioritized hardening checklist (block public 1433, disable sa/xp_cmdshell/unused features, enforce strong authentication, isolate backups, and audit privileged accounts).