Data theft has become standard practice in ransomware attacks. Encryption disrupts operations, but exfiltration creates lasting liability — even if you recover fully from backups, stolen data cannot be retrieved. Attackers leverage this by threatening to publish or sell sensitive data, creating pressure to pay regardless of your recovery capabilities.
The laws protecting consumer information continue to increase in number, scope, and penalty. Companies must protect their data to avoid mandatory breach notifications, regulatory investigations, and civil liability under frameworks including HIPAA, PCI-DSS, and state privacy laws. Criminal liability is possible in cases of gross negligence.
Core principles of data access controls: No single person should have end-to-end control over sensitive processes. Users and systems should have the minimum access required for their function. Accessing repositories of PII, PHI, or PCI data should require multi-factor authentication. Quarterly reviews should verify that access still matches job requirements and remove orphaned accounts. All access to sensitive data should be logged with sufficient detail to support forensic investigation.
File Shares (NAS)
File shares are a primary target because they’re easy to traverse and often over-permissioned. An attacker with access to one user’s credentials can frequently access far more data than that user’s job requires.
Access control fundamentals: implement least-privilege permissions, avoid broad “everyone” or “domain users” access, and disable inheritance where it creates excessive exposure. Organize shares by sensitivity level and business function rather than convenience.
Monitoring is critical. Ransomware encryption creates distinctive patterns — rapid sequential file access across many directories, mass file renames, or unusually high write activity. File Integrity Monitoring (FIM) and storage-level analytics can detect these patterns and trigger alerts or automatic countermeasures.
Periodic access reviews should verify that permissions match current job responsibilities. Users who change roles frequently retain access from previous positions; this accumulation creates unnecessary exposure.
Applications and Databases
Structured data in applications and databases often contains the most sensitive information — customer records, financial transactions, health data — but is accessed through application logic rather than direct file access.
Role-based access control (RBAC) within applications should mirror least-privilege principles. Users should have access to the functions and records their job requires, nothing more. Avoid shared service accounts; individual accountability requires individual credentials.
Database activity monitoring tracks queries and data access at the database level, independent of application logging. This catches both external attackers and insider threats, and creates an audit trail for compliance.
Service accounts connecting applications to databases are high-value targets. Use unique credentials per application, restrict permissions to required operations only, rotate credentials regularly, and monitor for anomalous usage.
Exfiltration Detection
Attackers need to move stolen data out of your environment. Detecting this activity is your last opportunity to limit the breach scope.
Network monitoring should trigger alerts and block large outbound transfers, connections to known file-sharing sites, and unusual data volumes to unfamiliar destinations. Baseline normal traffic patterns so anomalies are identifiable.
DNS tunneling encodes data within DNS queries to bypass traditional network monitoring. DNS analytics can detect the abnormal query patterns this technique creates.
Cloud application monitoring should track uploads to sanctioned and unsanctioned storage services. CASB (Cloud Access Security Broker) tools provide visibility into cloud data movement.
Data Loss Prevention (DLP) tools can identify sensitive data patterns (credit card numbers, SSNs, medical record numbers) in transit and block or alert on unauthorized transmission. DLP is not foolproof — attackers can encrypt or obfuscate data — but it raises the difficulty of casual exfiltration.