CDR (Content Disarm and Reconstruction): What it is, why it helps, and how it works

CDR (Content Disarm and Reconstruction)

What it is

CDR is a “clean-and-rebuild” filter for files. Instead of trying to guess if a document is bad, it strips out risky pieces (macros, hidden scripts, odd objects), then reconstructs a safe, working copy for you to open. For a deep dive, see our  
CDR guide

Why it matters

Most attacks now hide in everyday files—invoices, resumes, PDFs, Office docs. CDR turns those high-risk attachments into safer versions, so a single click doesn’t become a compromise.

How it works (30-second tour)

  • Ingest: the file is opened in a controlled space.

  • Disarm: active content and suspicious structures are removed or neutralized.

  • Rebuild: a clean copy (same text/images/layout) is produced for the user.
    Some solutions sanitize by policy (always remove macros), others use allow-lists (keep only known-good elements).

What CDR is great at

  • Stops file-borne malware without waiting for signatures.

  • Helps with zero-day file exploits.

  • Reduces help-desk tickets from “I opened a bad attachment.”

What CDR is not

  • A replacement for AV/EDR or sandboxing—CDR is one layer in the stack.

  • Perfect fidelity: complex files may lose non-essential features (e.g., macros, embedded media).

When to use it

  • Email gateways and file-upload portals (support, HR, vendor portals)

  • Shared folders, cloud drives, and collaboration tools

  • High-risk roles opening lots of external documents

Quick start

  1. Choose where to enforce (email, uploads, shared drives).

  2. Set a simple policy: remove macros/active content by default.

  3. Log what was removed; allow users to request the original if truly needed.

    Glossary (A–Z)

    All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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