What email attachment and link security is#
Attachment and link security covers scanning files and URLs in inbound mail (sandboxing, detonation, URL rewriting and time-of-click checks) and safe handling policies for outbound content.
Why it matters#
Malicious attachments and links remain the main payload delivery method for ransomware and credential theft.
How mailbox providers use it#
Gmail, Microsoft, and Yahoo combine authentication results, sender reputation, and recipient engagement into a placement decision made per message. Email attachment and link security feeds directly into that model, and weaknesses compound with other signals.
How to measure the impact#
- Baseline inbox placement with seed tests before any change.
- Make one change at a time and hold volume steady.
- Re-test after 48 to 72 hours; provider models need time to update.
- Track Postmaster Tools and SNDS alongside your seed results.
Improving it#
- Block executable and macro-enabled attachment types at the gateway.
- Enable URL rewriting with time-of-click reputation checks.
- Sandbox unknown attachments before delivery.
- For outbound, prefer links to authenticated portals over attachments for sensitive files.
Frequently asked questions#
Are PDF attachments safe?
Mostly, but PDFs can carry scripts and phishing links. Sandboxing and link rewriting still apply.