cisa-ed-25-02

About this tag
CISA ED-25-02 is an emergency directive issued by the Cybersecurity and Infrastructure Security Agency in response to a critical vulnerability affecting Microsoft Exchange hybrid deployments. The directive mandates urgent action for organizations still running on-premises Exchange servers in hybrid configurations with Exchange Online. Key requirements include migrating to the dedicated Exchange hybrid application and applying security updates to prevent exploitation. This directive is tied to a high-severity remote code execution flaw disclosed in August 2025 Patch Tuesday, which also involves a Kerberos elevation-of-privilege issue. Administrators must prioritize domain controller patching and hybrid app migration to avoid service disruptions and security risks.
  1. Cloud-Managed Remote Mailboxes: A Step Toward Retiring the Last Exchange Server

    Microsoft’s Exchange team has taken a decisive step toward finally letting organizations retire the last Exchange server in hybrid environments by adding cloud-managed remote mailbox support — a per-mailbox “flip-the-switch” that transfers Exchange attribute authority to Exchange Online while...
  2. Migrate to the Dedicated Exchange Hybrid App: Urgent Guide

    Microsoft’s Exchange team has given hybrid administrators a clear-but-urgent migration mandate: switch to the dedicated Exchange hybrid app and update on‑prem servers now, or face temporary disruptions in September and October followed by a permanent enforcement that will stop rich coexistence...
  3. August 2025 Patch Tuesday: Exchange Hybrid Crisis, Kerberos Flaw, and Cloud RCEs

    Microsoft’s August Patch Tuesday landed as a heavy, cross‑cutting security package that mixes high‑severity remote code execution (RCE) flaws, a publicly disclosed Kerberos elevation‑of‑privilege issue, and several cloud‑centric patches that were already mitigated on the service side—creating a...