Email Authentication Failures: How to Understand and Prevent Email Security Risks

Email authentication is an essential but often misunderstood aspect of email security—and the consequences of neglecting it can be severe.

Since your email program is a representation of your brand and reputation, we’re going to review the importance of authentication, the most commonly used protocols, how those protocols can fail, and what to do to prevent failure.

The significance and benefits of email authentication

Email is a key communication method in both personal and professional contexts.

As the use of email expands, so do the risks of suffering malfeasance from bad actors.

Cybercriminals and spammers constantly exploit email vulnerabilities for personal gain. Without robust authentication, these illegitimate senders can impersonate your domain, sending malicious emails that not only damage your reputation but also lead to data breaches that harm your subscribers.

Email authentication is the process of verifying that an email message is genuinely sent by the asserted sender.

By implementing authentication protocols, you as a sender become a less attractive target for malicious actors, reducing the likelihood of your brand being impersonated.

Additionally, your email recipients benefit by receiving fewer spam emails and other types of dangerous content.

While it’s impossible to completely shield subscribers from phishing attempts, implementing email authentication protocols can give you confidence that your emails are not contributing to the problem.

Common email authentication protocols

While email authentication protocols might seem complex and unnecessary, they combine into a powerful tool for securing your email communication.

The three most commonly used email authentication protocols are Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting and Conformance (DMARC). These protocols are intended to collectively verify the identity of an email sender by validating the mail server source, providing a digital email signature, and specifying a policy judgment for messages that fail both server validation and digital signature confirmation.

SPF authentication identifies which mail servers are authorized to send emails on behalf of your domain.

DKIM authentication adds a digital signature to an email message through public and private keys.

DMARC authentication sets the policy for how emails from the sender domain should be treated by the receiving server based on the authentication results of either SPF or DKIM. It also includes report delivery instructions for mailbox providers who deliver authentication results back to the sender.

Authentication protocol failures and their consequences

Now that we’ve established the importance of email authentication and understand the basic protocols, we need to explore the reasons behind authentication failures and the potential repercussions.

SPF can fail when the receiving mail server checks the SPF record for the sender’s domain and doesn’t find a valid match.

This can be due to either the sending server not being included in the sender’s SPF record, or the message header being manipulated during transmission, meaning the incorrect SPF record is listed (this can also occur during forwarding).

DKIM can fail when the sending domain’s keys do not match, or the signature has been tampered with during transit by an intermediary server.

DMARC doesn’t fail per se, but a lax policy can contribute negatively when an email fails both SPF and DKIM checks, thereby allowing illegitimate messaging to mix with legitimate messaging.

Protocol failure repercussions include:

• Domain spoofing: Spoofers can damage the reputation of the impersonated domain through spam or malicious emails.
• Phishing emails: Bad actors impersonate reputable organizations to trick recipients into divulging sensitive information or clicking on malicious links.
• Malware distribution: Attackers can spread malware through email attachments or links that appear trustworthy.
• Spam classification: Legitimate email messages with missing or incorrectly set up protocols can be sent to spam/junk folders or outright blocked by mailbox providers.

Preventing authentication failures

As you can see, authentication failures can create some big headaches for marketers, often in a small amount of time. At its core, email authentication just requires some attention to detail and ongoing monitoring to catch issues as early as possible.

Use this checklist to review your current authentication status and update where needed:

1. Implement all three protocols: Deploy SPF, DKIM, and DMARC together for maximum security.
2. Regularly update DNS (domain name system) records: Keep SPF, DKIM, and DMARC DNS records up to date with accurate information.
3. Monitor authentication reports: Review DMARC reports regularly to identify and address issues.
4. Educate your team: Ensure team members are aware of email authentication and potential risks.
5. Use email authentication tools: Tools and services such as Validity Everest can simplify the implementation and review of authentication protocols, and display DMARC reporting in a user-friendly fashion.

In summary, email authentication is an important tool for email security. Implementing SPF, DKIM, and DMARC can significantly reduce the risk of malicious attacks, protect domain and brand reputation, and enhance overall confidence in your email communications.

Don’t wait to take action—invest in email authentication protocols today to safeguard your email program tomorrow.

For a more in-depth breakdown of each protocol and how to implement it, watch our on-demand webinar, Why Authentication Matters: An Email Marketer’s Crash Course.