A Microsoft 365 email security-control bypass that lets attackers submit unauthenticated messages posing as internal users by leaving one SMTP field blank. The technique targets Exchange Online’s RejectDirectSend setting and does not represent a vulnerability in Microsoft software or in ReliaQuest systems; instead, it exposes a limitation in how the control evaluates Direct Send traffic. […]
The post Microsoft 365 Direct Send Bypass Lets Attackers Spoof Internal Users Without Credentials appeared first on GBHackers Security | #1 Globally Trusted Cyber Security News Platform.