Misconfigured Email Routing Enables Internal Domain Phishing
🔒 Microsoft warns that threat actors are exploiting misconfigured email routing and lax spoof protections to send phishing messages that appear to originate from an organization’s own domain. The Microsoft Threat Intelligence team says the tactic surged since May 2025 and is commonly deployed via Tycoon 2FA phishing-as-a-service kits. Attacks aim to steal credentials, bypass MFA via AiTM techniques, and enable follow-on fraud or BEC, often using fake invoices, HR notices, or shared-document lures. Organizations should enforce DMARC reject and strict SPF policies, validate third-party connectors, and disable Direct Send if unnecessary.
