Western Alliance Bank Data Breach Impacts 22,000 Customers

Western Alliance Bank suffered a data breach affecting 21,899 customers between October 12-24, 2024.

Malicious actors exploited a zero-day vulnerability in third-party file transfer software, enabling unauthorized access to sensitive personal and financial information, such as names, Social Security numbers, dates of birth, driver's license numbers, financial account details, tax identification numbers, and passport information.

Malicious actors, later identified as the Cl0p ransomware group, leveraged a zero-day vulnerability in a widely-used third-party file transfer tool to bypass traditional defenses.

This enabled them to access the bank’s environment and exfiltrate sensitive data before detection mechanisms could respond.

Continuous Monitoring & Threat Detection: Implement real-time monitoring to detect unauthorized access, particularly through third-party integrations. Use behavioral analytics to flag anomalous activity before data exfiltration occurs.

Robust Third-Party Risk Management: Conduct comprehensive security assessments of all third-party software and services. Maintain an up-to-date vendor inventory and enforce continuous oversight for tools handling sensitive or regulated data.