Stefan Mileschin

Servers stop delivering mail

Microsoft Exchange on-premise servers cannot deliver email starting on 1 January, 2022, due to a "Year 2022" bug in the FIP-FS anti-malware scanning engine.


Starting with Exchange Server 2013, Microsoft enabled the FIP-FS anti-spam and anti-malware scanning engine by default to protect users from malicious email. According to numerous reports from Microsoft Exchange admins worldwide, a bug in the FIP-FS engine is blocking email delivery with on-premise servers starting at midnight on January 1st, 2022.

Security researcher and Exchange admin Joseph Roosen said that this is caused by Microsoft using a signed int32 variable to store the value of a date, which has a maximum value of 2,147,483,647. However, dates in 2022 have a minimum value of 2,201,010,001 or larger, which is greater than the maximum value that can be stored in the signed int32 variable, causing the scanning engine to fail and not release mail for delivery.

https://fudzilla.com/news/54133-year...osoft-exchange