Best Practices in Handling Email Attachments: What You Need to Know

Email attachments have become an essential part of our daily communication, enabling us to share documents, images, and other files quickly and conveniently. Whether collaborating with colleagues, sending invoices to clients, or exchanging reports with external stakeholders, attachments make it easy to share information without the need for complex file-sharing platforms.

However, while attachments simplify information exchange, they also introduce significant risks and inefficiencies if not handled properly. From security vulnerabilities such as malware and ransomware to bloated inboxes and storage issues, poor attachment management can lead to data breaches, performance slowdowns, and even regulatory non-compliance.

Let’s explore the best practices for handling email attachments efficiently and securely. We’ll cover why these practices matter, who needs them, real-world use cases, and alternative solutions that can help you manage attachments more effectively. By the end, you’ll have a comprehensive understanding of how to optimize your attachment handling process, making it both secure and efficient.

What Are Email Attachments and Why Do They Matter?

An email attachment is a file sent along with an email message. It could be anything from a simple document or image to more complex files such as spreadsheets, PDFs, or compressed folders. Attachments are commonly used for sharing project updates, contracts, presentations, and other critical documents.

While they are indispensable for collaboration, attachments come with certain challenges:

Security risks: Email attachments are a common carrier for malicious content. Hackers frequently disguise malware, ransomware, and phishing attempts in seemingly innocuous file attachments. Opening such files can compromise systems, steal sensitive data, or trigger massive security breaches.
Storage and performance issues: Large or excessive attachments can consume substantial storage space on both personal devices and email servers. Over time, this can slow down email performance and lead to storage limitations, which can affect productivity.
Compliance concerns: Industries with strict data protection regulations (e.g., GDPR, HIPAA, FINRA) require secure handling of sensitive information. Improper attachment management can result in legal and financial consequences for failing to meet compliance standards.

Why Do We Need Best Practices? Adopting best practices for email attachments ensures:

Data security and privacy: Prevents exposure to malicious content and reduces the risk of data breaches.
Efficient file management: Helps avoid inbox clutter, enhances performance, and streamlines document retrieval.
Compliance with regulations: Ensures adherence to industry standards by enforcing encryption, size limits, and secure sharing policies.
Improved productivity: Reduces issues caused by oversized emails and makes collaboration smoother and more organized.

Who Needs Best Practices for Email Attachments?

Best practices for handling email attachments are essential across all industries and roles, as email communication is ubiquitous in both personal and professional settings. However, they are particularly critical for:

IT and Security Teams: These teams are responsible for protecting the organization’s infrastructure from security threats. Ensuring proper attachment handling minimizes the risk of email-based attacks and data breaches.
Legal and Compliance Departments: Organizations in industries like healthcare, finance, and law are bound by strict data privacy regulations. Secure attachment practices help maintain compliance with standards such as HIPAA or SOX, avoiding legal repercussions.
Business Professionals: Employees across all departments routinely share reports, contracts, and proposals via email. Efficient attachment management ensures smooth collaboration while protecting sensitive data.
Healthcare and Financial Services: These sectors regularly handle sensitive patient and financial data. Using encrypted email attachments and secure file-sharing platforms prevents unauthorized access and ensures data integrity.
Freelancers and Consultants: Independent professionals frequently exchange documents with clients and vendors. Adhering to best practices protects their intellectual property and prevents accidental data exposure.

Best Practices for Handling Email Attachments

✅ 1. Use File Sharing Links Instead of Attachments

One of the most effective ways to handle large or sensitive files is by using secure file-sharing services like OneDrive, Google Drive, Dropbox, or SharePoint. Instead of directly attaching large files, you can upload them to cloud storage and share a link. This not only reduces the strain on email servers but also enhances security and version control.

Why This Matters:

Reduced server load: Large attachments can slow down email servers, making them less responsive. Using links instead reduces the size of the email, enhancing performance.
Version control: Sharing cloud-based links ensures that recipients always have access to the most up-to-date version of the file, preventing versioning conflicts.
Enhanced security: Cloud platforms allow you to set expiration dates, view-only permissions, and password protection on shared links, adding an extra layer of security.

📌 Example:
Instead of attaching a 50 MB PDF document, upload it to OneDrive and share a secure link with expiration and view-only permissions. This ensures the recipient receives the latest version without overloading their inbox or your email server.

🔒 2. Encrypt Sensitive Attachments

When sending confidential or sensitive data, always encrypt the file before attaching it. Encryption ensures that only the intended recipient with the correct decryption key can access the content. This is particularly important for industries like healthcare, finance, and legal, where data privacy is paramount.

Methods of Encryption:

Password-Protected PDFs or ZIP Files: Adding a password to sensitive documents before attaching them ensures that even if the email is intercepted, the content remains inaccessible.
End-to-End Encryption (E2EE): Use encrypted email services like ProtonMail or Tutanota to ensure only the recipient can read the message and its attachments.
Microsoft Outlook Encryption: Outlook offers native encryption features for Office attachments, adding an extra layer of protection with minimal effort.

🔹 Tip:
Share the decryption password through a different communication channel, such as SMS or a phone call, to minimize the risk of interception.

⚠️ 3. Be Cautious of Unknown or Suspicious Attachments

Attachments are a common vector for malware and phishing attacks. Always verify the sender’s email address before opening any attachment, especially if the message seems suspicious or unexpected.

Red Flags to Watch Out For:

Unexpected attachments from unknown senders or colleagues you don’t normally communicate with.
File extensions that are commonly associated with malware (e.g., .exe, .scr, .bat, or .js).
Poorly written or generic messages with vague subject lines or instructions to “click and open.”

Preventive Measures:

Use advanced email security solutions like Mimecast, Proofpoint, or Barracuda to automatically scan and quarantine suspicious attachments.
Enable attachment filtering rules that block high-risk file types.

📄 4. Implement Attachment Size Limits

Many email servers have size limits for attachments (often around 25 MB). Sending large attachments can slow down email servers, cause delivery failures, and overwhelm recipient inboxes. To prevent these issues, adhere to size restrictions and use alternative methods for large files.

Best Practices for Large Files:

Compress large files before attaching them using ZIP or RAR formats. This reduces the overall size while maintaining the content.
Use cloud storage links for anything over 10-15 MB to avoid performance issues.
Split large files into smaller parts if necessary, making them easier to send and receive.

✅ 5. Follow Organizational Policies for Attachment Handling

Organizations often have internal policies regarding what types of files can be attached, maximum sizes, and security protocols. Following these guidelines ensures compliance with security standards and reduces risks.

Common Policies Include:

Restricting executable file attachments: To prevent the spread of malware.
Limiting external email attachments: For data protection purposes.
Automatically encrypting attachments: Containing sensitive or personally identifiable information (PII).

🔍 6. Use Email Attachment Auditing and Tracking

Many organizations overlook the importance of auditing email attachments. Tracking who sent and received attachments is crucial for security, compliance, and incident response.

Tools for Auditing:

Microsoft 365 Compliance Center: Monitors and tracks email attachments for regulatory audits.
Proofpoint Essentials: Provides visibility into attachment activity, helping identify suspicious patterns or breaches.

Real-World Use Cases

✅ Use Case 1: Healthcare Industry Compliance A hospital uses SharePoint Online to store patient records and share access links instead of email attachments. This method ensures HIPAA compliance, as access is restricted to authorized personnel only.

✅ Use Case 2: Finance Industry Efficiency A bank uses Microsoft Defender for Office 365 to scan email attachments for potential threats before delivering them, ensuring that all attachments meet compliance and security standards.

References

Proper handling of email attachments is essential for both productivity and security. By following these best practices, you can significantly reduce security risks, enhance compliance, and streamline file sharing.