Why Email Attachments Are Not Safe for Sensitive Files
Email is convenient, but it’s a poor choice for sending sensitive files. From accidental forwarding to long-lived backups on third‑party servers, attachments create risks that are hard to control. If you need privacy, control, and auditability, there are better options.
The core problems with email attachments
- No end‑to‑end encryption by default
Most email is transported with TLS between servers, but once it reaches the provider it’s typically stored unencrypted at rest and readable by the service. If an account is compromised, your attachment is exposed.
- Forwarding multiplies exposure
Attachments get copied with every forward or reply‑all. You lose all control the moment someone shares the message—there’s no expiry, no download limit, and no way to revoke.
- Permanent copies in backups and archives
Mailboxes are backed up, journaled, and archived for years. Even if you delete a message, copies can persist in server backups, local mail clients, and recipients’ devices.
- Mistyped recipients and shared inboxes
One wrong character in an address can leak data. Shared inboxes (support@, info@) increase the number of people who can see attachments.
- Provider and security tooling inspection
Spam and malware scanners routinely open and scan attachments. That’s necessary for safety, but it also means extra systems can access your file.
- Metadata you didn’t mean to share
Documents often contain author names, revision history, hidden sheets, GPS data, or embedded thumbnails. Email provides no guardrails to strip this automatically.
- Size, reliability, and deliverability limits
Many providers cap attachments around 20–35MB. Larger files get blocked, silently dropped, or auto‑converted to cloud links you don’t fully control.
What to use instead
Use a secure link that you control:
- Add a password known only to sender and recipient
- Set a short expiry so the link dies on its own
- Limit total downloads to prevent uncontrolled spreading
- Replace the file with a new version without exposing prior copies
Comfyfile makes this simple—no recipient account required.
A safe handoff workflow (step‑by‑step)
- Upload your file to Comfyfile
- Set a strong, unique password
- Choose an expiry (e.g., 24 hours or 7 days) and limit downloads (e.g., 1–3)
- Copy the link and send it via email or chat
- Send the password through a different channel (e.g., SMS or a call)
- If you need to revise the file, upload a new version and share a fresh link
Why it works:
- Expiry and limits reduce blast radius if the link leaks
- The password blocks casual forwarding from exposing your data
- Versioning with fresh links avoids stale copies living forever in inboxes
Quick checklist before you share
- Strip hidden metadata from docs and images
- Export a PDF copy for compatibility when relevant
- Double‑check recipient addresses and avoid shared inboxes for sensitive docs
- Put the password in a different channel than the link
- Don’t reuse passwords you use elsewhere
FAQ
Isn’t email encrypted?
Partially. TLS protects the hop between servers, but providers typically decrypt and store your mail. That’s not end‑to‑end.
Can I recall an email if I made a mistake?
Practically speaking, no. “Recall” features only work in narrow cases within one provider. Assume anything sent could be copied or forwarded.
What about cloud links auto‑generated by email services?
They’re better than raw attachments, but you still need passwords, expiries, and download limits to control risk.
Bottom line
Email is great for conversation—not for sensitive file transfer. Use a password‑protected, expiring link with download limits so you can share confidently and revoke access when it’s no longer needed.
Try it with Comfyfile: upload, add a password, set an expiry, and share in seconds.