Five Steps to Keep Your Email Attachments Secure

Although they are essential in most businesses, email attachments can be used to spread malware infections, gain access to systems, and leak confidential information. Here are five ways to keep your email attachments secure:

#1: Block Dangerous Attachment Types

IT departments should consider creating a policy that blocks email attachments with potentially dangerous formats, such as .exe files or password protected zip files. If these files need to be sent or received legitimately, an alternative system should be used, such as a portal for securely transferring files.

#2: Use Multiple Antivirus Engines to Scan Attachments

The recent outbreak of the 'FW: Daily report email' has yet again emphasized the lag time between the emergence of a malware threat and when various anti-malware engines are able to detect it. This lag in detection means that organizations are potentially exposed if they are just using one or two antivirus engines. By using four or more antivirus engines you can significantly increase the chance that a new threat is quickly detected and remediated.

#3: Content Check Email Attachments

Files containing sensitive data should not be sent via email. Central email policies should be set in order to block any email attachments containing confidential data such as credit card information or social security numbers that may be mistakenly sent out via email. Users should be given alternative methods for transferring files securely so that they do not need to revert to email.

#4: Sanitize Email Attachments

Targeted attacks, zero-day attacks and new malware for which antivirus definitions have not yet been released, can potentially get past your anti-malware engine and end up in your users' inboxes. To prevent unknown threats, email attachments should be sanitized by converting files to a different format and removing any possible embedded threats. For instance by converting a Word document to a .pdf file, any potentially harmful scripts can be removed before they can do any damage.

#5: Detect File Type Spoofing

In order to bypass email security filters and fool users into opening attachments, attackers can rename extensions to make a malicious file look harmless. Most users know that clicking on an .exe file attached to an email from an unknown sender is probably not a good idea, but if that file has been made to look like a .txt file they might be tempted to open it.

Implementing these steps may seem a bit overwhelming, but adding a second layer of defense on top of your existing email security solution such as MetaDefender Email, along with antivirus multi-scanning scanning, data sanitization and file verification capabilities of MetaDefender Core, can help keep your organization's email attachments secure.

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