Microsoft Exchange and Active Directory Blog
The CERT-Bund warns on X of more than 15,000 Exchange servers in Germany that are openly accessible from the Internet with at least one vulnerability. Some of the vulnerabilities are already being actively exploited. In March 2024, the BSI had already warned of 17,000 Exchange servers that are openly accessible from the Internet and contain known vulnerabilities. The ... Read more
When configuring mailbox permissions for a group, the following error may occur: The user "testgruppe" was found in Active Directory but isn't valid to use for permissions. Try an SMTP addressinstead. Permissions for groups can only be assigned if it is a security group. For a security group, the values for ... Read more
The end of support for Exchange Server 2019 and 2016 is approaching. Support for both versions will end on October 14, 2025, from which date only Exchange Server SE (Subscription Edition) will be supported. However, upgrading to Exchange SE is much easier this time than before, at least if Exchange Server 2019 is already in use. Here is a ... Read more
Yesterday, security updates were released for Exchange Server 2016 and Exchange Server 2019. In connection with Outlook and Exchange Server 2019, there are now increasing reports of problems with the search. Admins are reporting problems on the Exchange Team Blog and in the comments to my post. The search apparently produces the error message ... Read more
Microsoft has released new security updates for Exchange Server 2016 and Exchange Server 2019 today. The security update closes the remote execution vulnerability CVE-2024-26198 with the severity level "Important". The vulnerability is not currently being actively exploited, but Microsoft recommends that the update is installed quickly. Click here to download the security update: After installing the March ... Read more
Under certain circumstances, Microsoft Office 365 and Exchange Server allow access to attachments and images in emails without the need for authentication. In most cases it should be difficult to exploit this problem, but reader L. Herzog writes to me that this problem could be exploited in his environment. L. Herzog has ... Read more
The critical vulnerability CVE-2024-21410 in Exchange Server, which was made public on February 13, 2024, is now being actively exploited. The vulnerability CVE-2024-21410 allows attackers to perform an NTLM relay attack (pass the hash). In this case, attackers can trick a client such as Outlook into logging on to a malicious relay in order to obtain the NTLM credentials. The ... Read more
Microsoft has announced that Exchange 2019 CU14 will not be released this year. The CU14 has been postponed to January 2024. Just last year, the publication of Exchange CUs was changed so that only 2 CUs were to be published per year. The plan was to publish one CU in March and another in September. How ... Read more
Microsoft has released new security updates for Exchange Server 2016 and 2019. The updates fix the following vulnerabilities, which are all marked as "Important": Click here to download the updates directly: With the November security updates, the "Certificate signing of PowerShell serialization payload" feature is enabled by default. Before installing the November update ... Read more
Microsoft today released new security updates for Exchange Server 2016 and Exchange Server 2019. The update closes the remote execution vulnerability CVE-2023-36778 and provides a better solution for the vulnerability CVE-2023-21709 from August. There were problems with the August security update and the update was temporarily recalled. The update from October for CVE-2023-36434 ... Read more
