Despite the rise of chat apps, email remains the most popular communication channel for businesses.

And usage continues to grow.

According to Statista, the number of global email users amounted to four billion in 2020 and is projected to reach 4.6 billion users by 2025.

Because email plays a significant role in corporate communications (both internal and external), it’s also the most likely channel to expose critical information.

Email data loss prevention (DLP) is vital for IT leaders in protecting sensitive data from security breaches.

If your company is subject to compliance laws (and really, which company isn’t?), you must take steps to guard against the malicious or accidental disclosure of sensitive data via email to avoid costly fines or even criminal prosecution.

In this article, we’ll cover everything you need to know about email DLP, including what email DLP is, the types and signs of email data loss, and how to prevent it.

Data loss prevention, or DLP, is an umbrella term covering techniques and strategies businesses use to keep sensitive data safe. Email data loss prevention is a type of DLP that attempts to stop data loss caused by email transmission.

While businesses often have information security policies covering the acceptable use of email, mistakes happen. According to the 2021 Verizon DBIR, 85% of breaches (n = 4,492) involve the human element.

Whether it’s social engineering meant to alter human behavior, misdelivered information, or making humans an active (albeit unintentional) participant in the attack, the human layer has emerged as the most vulnerable part of the organization. Email DLP software helps prevent sensitive data loss by mitigating the risk of human error (a common factor in email usage), malicious data loss exfiltration, and attackers using targeted email attacks to exfiltrate sensitive user and organizational-specific data.

Email data loss happens when people send confidential or sensitive data, including personal information via email - either unknowingly or maliciously - or through email attacks with the goal to exfiltrate sensitive data. This data can expose both customers and employees alike.

This type of “sensitive data” can include:

• Credit card numbers

• Social Security numbers

• Bank account numbers

• Login IDs and passwords

• Health records

• Intellectual property

• Trade secrets and intellectual property

Basically, it’s all the information you want to keep out of the wrong hands, not only for security and privacy purposes, but also to avoid potential legal, financial, and reputational penalties.

There are three main types of data loss: Accidental Data Loss, Malicious Data Loss, and Data Exfiltration

Accidental Data Loss

Accidental data loss happens more frequently across organizations of all sizes, mainly from employees unknowingly sharing sensitive or confidential information.

Examples of accidental data loss include:

• Attaching critical data to an email and sending it to the wrong person

• Using “Reply All” instead of “Reply,” resulting in widespread data distribution

• Making a typo that changes the recipient’s email address

• Sharing sensitive data over email with someone who is spoofing a trusted entity

Malicious Data Loss

While accidental data loss is common, employees or individuals with access to sensitive or confidential information can purposefully harm organizations through malicious data loss.

Examples of malicious data loss include:

• Copying confidential files or information to an external device

• Forwarding sensitive information to a personal or external address

• Sharing proprietary information outside of the organization

Data Exfiltration

Several data loss incidents have become newsworthy due to the attack vectors used by sophisticated cybercriminals.

Examples of attacks with the goal of data exfiltration include:

• Ransomware

• Spear phishing

• Business Email Compromise (BEC)

• Malicious attachments via email

• Vendor or third-party compromise

• Corporate espionage

Whether malicious or accidental, email data loss can have dire consequences. Here are five common indicators that your data might have been exposed.

1. Unusual Mail Rules

Is an employee auto-forwarding business mails to their personal email address? Sending company emails to personal accounts en masse can be a red flag.

2. Wrong Recipients

Speed kills. Replacing an “i” with an “o” in the recipient’s email address means someone just sent your company’s financial report to a stranger — or a competitor.

3. Suspicious Download Activity

Has an employee who rarely downloads documents suddenly downloaded a dozen in the last hour? Be on the lookout for activities that don’t fit the pattern of normal behavior.

4. Confidential Data Leaks

Trust is earned, not automatically given. It’s possible that an employee could share a confidential spreadsheet containing customer data with an unapproved third-party analyst — either accidentally or on purpose.

5. Suspicious/Anomalous Email Activity

Has an employee been sending a large number of emails in the middle of the night, or sending sensitive data to a contact they have never emailed before. Unusual behavior can be a sign of sensitive or confidential data loss.

Establishing email security best practices and training employees on the dangers of email data breaches is always a good idea. However, it’s not always sufficient to fully protect against email data exfiltration incidents, especially when human error is the primary cause.

Email Data Loss Prevention software adds an extra layer of protection by monitoring, detecting, and taking action to prevent the malicious or unintended sharing of sensitive data over email: blocking emails from being sent, encrypting sensitive data within email communications with unauthorized recipients, deleting emails across mailboxes.

If your company uses email, then yes, you need email DLP.

Even the most careful analysis of outgoing messages by humans can miss the transmission of information that could threaten your company and your livelihood. Therefore, email DLP should be considered a key component of your company’s cybersecurity strategy.

Here’s how our email DLP software protects your business:

Detects when unencrypted passwords, SSNs, bank account details, and other sensitive information is shared with external parties.

Increases DLP accuracy with natural language understanding and other advanced techniques that identify sensitive data within email context.

Uncovers communication insights for targeted security interventions, e.g., most noncompliant individuals, and DLP violations by department.

Saves time by setting automated remediation workflows for specific departments and data loss violation types with custom alerting.

Prevents data loss over email with automatic remediation actions that stop emails that contain sensitive data from leaving your organization.

Email DLP is a necessary tool in the fight against cybercrime and accidental (or negligent) data loss. Investing in prevention solutions protects your company and your employees by preserving the integrity of your data and ensuring that you are compliant with industry standards and regulations.