Exchange 2016

Microsoft has announced that the Exchange Server cumulative updates (CUs) are switching to a biannual release schedule. The company currently releases CUs quarterly, but this slow release cycle will allow organizations to keep their Exchange servers up-to-date more easily. “We are moving to a release cadence of two CUs per year – releasing in H1…

Turla, a Russian cyber-espionage group is reported as being behind an attack on Exchange on-premises servers that uses transport agents to capture and process messages for selected users. It’s an attack vector that hasn’t been seen before and raises the question of how often administrators should review transport agents active on their servers. The important point is that unless your network is compromised, hackers cannot install transport agents on Exchange servers and this attack is more theoretical than practical.

Exchange 2019 has been around for six months. It’s a good time to consider if on-premises organizations should upgrade or stick with the version of Exchange they run today. Exchange 2019 is a solid release, even if Microsoft’s engineering efforts are largely focused on the cloud these days. Of course, moving to Exchange Online is an option too, but perhaps not for the dedicated on-premises deployments.

The recent exposure of a privilege elevation vulnerability that exists in the control Exchange has over Active Directory and EWS push notifications is fixed by cumulative updates for Exchange 2013, Exchange 2016, and Exchange 2019 and a roll-up update for Exchange 2010 SP3. These changes mark an architectural modification for Exchange, something that Microsoft is loathe to do outside major releases. Install the updates now!

No fix is available yet for the Exchange vulnerability reported by Dirk-jan Mollema and described in CVE-2018-8581. Apart from deploying a split permissions model, no out-of-the-box mitigation exists today. Microsoft is working actively to fix the problem and in the meantime, the brains of the Exchange community are hard at work to come up with possible solutions.

A newly-discovered vulnerability in Exchange potentially allows attackers to gain control over Active Directory. Since Exchange 2000, Exchange has been a highly-privileged server that’s tightly connected to Active Directory. Add in some NTLM weakness, Exchange Web Services push notifications, and everything comes together for the bad guys.

Microsoft has new tools to migrate public folders (the “cockroaches of Exchange”) to Office 365 Groups. Sounds good. The good news is that the tools work, even if they need a lot of manual oversight. ISVs offer tools to do the same job with more automation. The choice is yours!

Surprisingly, Microsoft has never included a central method to manage user autosignatures within the cloud or on-premises versions of Exchange. Which means that you must let users manage their signatures, build your own tools, or deploy a commercial solution.

Microsoft now supports the migration of modern public folders to Exchange Online. ISV solutions allow you to migrate public folders to other places, like Office 365 Groups and shared mailboxes, which seems like a lot more interesting.