Microsoft Purview compliance portal: Data Loss Prevention - Detection of True file type in EXO DLP Beta
Data as of 2 hours ago (9 September 2026)
This item was no longer present in the roadmap feed as of 6 September 2026. Microsoft removes entries for several reasons — cancelled, merged into another entry, or reorganised — and the feed does not say which.
Description
Traditionally, Exchange has relied solely on the file extension (e.g., .docx, .pdf) to identify the type of an attachment. However, this approach can be bypassed if a file is renamed with a misleading extension. To address this, we’re enhancing our detection logic to go beyond just the visible file extension. With this update, even if a file’s extension is altered, Exchange will evaluate the actual content of the file to determine its true type. This ensures that policies based on file type—such as “File extension is…”—remain effective and secure, even in cases of renamed or disguised attachments. This improvement provides customers with a more robust and reliable way to enforce compliance and security rules around file sharing.
Change history
Added to the roadmap 9 May 2025. Tracked here since 1 September 2026. Earliest target we recorded: August 2025 (since tracked — Microsoft may have moved it before we started watching).
Nothing has changed on this item since tracking began on 1 September 2026. Changes appear here as Microsoft updates the feed.