Year 2022 bug cripples Microsoft Exchange server

A massive bug in the Microsoft Exchange server has been causing problems since 01 January 2022. Thanks to the Year 2022 bug, emails can no longer be delivered, the reason being the internal malware scanner.

Year 2022 bug strikes

The turn of the year did not leave Microsoft Exchange email services unscathed, as the Year 2022 bug or “Y2K bug” has been causing problems since New Year 2022. The FIP-FS Scan Engine, Exchange’s virus scanner, has been issuing an error message since the turn of the year and refusing to deliver emails as a result: “Can’t Convert ‘2201010001’ to long,” the text reads.

The short-term solution to the problem is to temporarily disable the malware scanner. To do this, you need the Disable-Antimalwarescanning.ps1 script. Alternatively, the Powershell command “Get-Transportagent Malware Agent | Disable-Transportagent” can be executed – Microsoft has shown how to do this in an older post.

The FIP-FS anti-spam and anti-malware scanning engine has been enabled by default by Microsoft since Exchange Server 2013. Disabling it is currently the only solution, but it only makes sense if you use a different malware solution for your email service.

Microsoft is working on a solution

The Microsoft Exchange Year 2022 bug only occurs on self-hosted servers. Microsoft itself has already confirmed the bug, the announcement states:

“We have addressed an issue that causes messages to get stuck in Exchange Server 2016 and Exchange Server 2019 transport queues. The issue relates to an error in the year-end date validation process and not a bug in the AV engine itself.”

Active measures on the part of users are currently required to fix the bug, he said. Microsoft offers an automated and manual solution for this purpose. However, they are working to fix the bug as soon as possible, he added.

Security researcher and Exchange administrator Joseph Roosen shared via Twitter on Jan. 01 that Microsoft uses a signed int32 variable to store the date. It has a maximum value of 2,147,483,647, but new dates in 2022 have a minimum value of 2,201,010,001 and are therefore simply too long for Microsoft Exchange.