Nearly 22,000 Microsoft Exchange servers vulnerable to hijack attacks
Summary
A critical authentication bypass vulnerability affects nearly 22,000 unpatched Microsoft Exchange servers, potentially allowing attackers to hijack all user mailboxes. The vulnerability is being actively exploited.
IFF Assessment
The article details a high-severity vulnerability that exposes a large number of servers to potential hijacking, posing a significant risk to defenders.
Severity
The CVSS score is estimated based on the 'critical' severity and the impact of 'hijack all user mailboxes' due to an 'authentication bypass vulnerability', suggesting high impact and exploitability.
Defender Context
This highlights the persistent threat of unpatched legacy systems, particularly in widely used infrastructure like Microsoft Exchange. Defenders must prioritize patching these servers immediately and implement strong monitoring for signs of exploitation to prevent widespread mailbox compromise.