Critical security vulnerability in Outlook

Updates have been released for Outlook 2013 and Outlook 2016 to close two critical security vulnerabilities. With both vulnerabilities, it is possible to execute malicious code on the computer. With one of the vulnerabilities, it is sufficient to receive an email with a malicious attachment. The attachment does not even have to be opened. The corresponding CVEs can be found here: CVE-2018-0852 | ... Read more

Exchange 2016: SMTP Connector and wildcard / SAN certificates

Anyone using Exchange 2016 in conjunction with a wildcard certificate should also configure the receive and send connectors accordingly. This may also be necessary for SAN certificates. If the SAN certificate contains the domain name as the "Common Name (issued for)" and not the corresponding server name of the Exchange server, problems may occur, for example, when encrypting the SMTP connection using STARTTLS. ... Read more

Sophos UTM and DKIM

DKIM, also known as DomainKeys, is a procedure for determining the authenticity of emails. The basic functionality is explained quite simply: The sending mail server calculates a hash value for each mail it sends and appends this hash to each mail in the e-mail header. The receiving mail server can evaluate the signature and also determine the ... Read more

Exchange 2016: Offline address book (OAB) cannot be downloaded (0x8004010F)

If Outlook cannot download the Offline Address Book (OAB) from an Exchange 2016 server, the following error message is displayed: Error (0x8004010F) while performing the task: Error during operation. An object cannot be found. Unfortunately, this error message is quite general and can be caused by various problems. The cause of the error was in this ... Read more

Open Source AntiSPAM Appliance: Proxmox Mail Gateway

The Austrian company Proxmox has published the spam filter "Mail Gateway" as open source under the GNU AGPL v3 license. This means that the spam filter can be used free of charge. I've been looking for a SPAM filter for test environments for a while now, so I'm taking a closer look at the Proxmox solution. Here is an overview of the ... Read more

Exchange Autodiscover Whitepaper - Updated version

I have just uploaded an updated version of the "Exchange Autodiscover Whitepaper". Since the behavior of Outlook 2016 in connection with Autodiscover has changed somewhat in November 2017, I have adapted the whitepaper accordingly. Outlook now prefers Autodiscover in conjunction with Office 365, which leads to problems if the user has an Office 365 account. Read more

EUGO: First meeting in the new year

The first meeting of the Exchange User Group OWL (EUGO) in 2018 will take place on March 2, 2018 as usual at the Allegro Habichtshöhe restaurant in Bielefeld. Everyone who is interested in talking shop about current Microsoft technologies and topics in a relaxed atmosphere is cordially invited. We do not have a fixed agenda on the program, as usual we do not want to ... Read more

Exchange Server and Spectre

Microsoft has published an article on Exchange Server and Spectre (speculative execution side-channel). As this is a vulnerability in the processors, Exchange Server is also affected. There are a few things to note. Microsoft writes the following: As these are hardware level attacks targeting x64-based and x86-based processor systems, all supported versions of ... Read more

Visualize Exchange Message Tracking Logs with PowerBI

The Exchange Message Tracking Logs are not only helpful to analyze MailFlow problems, but are also great for generating statistics. My script "Exchange Reporter" uses the message tracking logs to generate some statistics on received/sent mails. The Message Tracking GUI is also based on the Message Tracking Logs. The Exchange Reporter ... Read more

Exchange 2016: EventID 1006 - Event Dispatchers Catching Up

On Exchange 2016 servers, the following event is sometimes written to the application log every 30 minutes Source: MSExchangeDiagnostics Event ID: 1006 The performance counter '\\EXCHANGE\MSExchange Assistants - Per Database(msexchangemailboxassistants-fwdb)\Event Dispatchers Catching Up' sustained a value of '2.730,00', for the '30' minute(s) interval starting at '10.01.2018 19:39:00'. Threshold breached since '25.12.2017 21:09'. None Trigger Name:EventDispatchersCatchupQueueTrigger. Instance:msexchangemailboxassistants-fwdb This ... Read more