Outlook: Mail Merge (Advanced) on Outlook on the Web and new Outlook for Windows

🚨 The Signal: Outlook's new advanced mail merge feature allows personalized emails to individual recipients. This increases the risk of sophisticated phishing and social engineering attacks by making malicious emails appear more legitimate and targeted.

The Impact

All users are affected, increasing the risk of successful phishing, social engineering, and data exfiltration.

• End Users: Increased exposure to highly personalized phishing attacks.
• Security Team: New challenge in detecting sophisticated internal and external phishing.
• Data Owners: Higher risk of sensitive data being exfiltrated via personalized emails.
• Compliance Teams: Potential for non-compliance with data handling policies due to misuse.

The Action

1. Review and update existing security awareness training modules to include advanced mail merge phishing scenarios.
2. Enhance email filtering rules to detect highly personalized content anomalies and suspicious sender patterns.
3. Implement or strengthen Data Loss Prevention (DLP) policies to monitor and block sensitive data in outbound emails.
4. Educate users on the risks of personalized emails and the importance of verifying sender identity.
5. Monitor audit logs for unusual patterns of mass email sending, especially from privileged accounts.

Domain: Exchange · Impact: high · Workload: Exchange Online