Microsoft Issues Emergency Fix for Exchange Y2K22 Bug That Impacts Email Delivery

Colin Thierry Colin Thierry

Microsoft rolled out an emergency patch on Jan. 1 to fix the Y2K22 bug that has impacted its email delivery system. The Y2K22 bug caused email messages to be stuck on Exchange Server locations because of a validation error that occurred somewhere around the final hours of 2021.

According to multiple reports, the Y2K22 bug was caused by a glitch in the FIP-FS anti-malware scanning engine that Microsoft utilizes to protect users starting with Exchange Server 2013.

“This is not an issue with malware scanning or the malware engine, and it is not a security-related issue,” the Microsoft Exchange Team said in a statement. “The version checking performed against the signature file is causing the malware engine to crash, resulting in messages being stuck in transport queues.”

“We have now created a solution to address the problem of messages stuck in transport queues on Exchange Server 2016 and Exchange Server 2019 because of a latent date issue in a signature file used by the malware scanning engine within Exchange Server.”

In order to remedy this issue, Microsoft asked its customers to follow some steps. The actions can be automated with the scan engine reset script from a link provided by Microsoft or they can be performed manually.

Microsoft noted that the scanning engine’s new version is now fully supported and works as expected.

“The newly updated scanning engine is fully supported by Microsoft,” the company said. “While we need to work on this sequence longer term, the scanning engine version was not rolled back, rather it was rolled forward into this new sequence. The scanning engine will continue to receive updates in this new sequence.”

About the Author

About the Author

Colin Thierry is a former cybersecurity researcher and journalist for SafetyDetectives who has written a wide variety of content for the web over the past 2 years. In his free time, he enjoys spending time outdoors, traveling, watching sports, and playing video games.