Discovering that your email domain has been spoofed can be a concerning experience. It means that unauthorized parties are sending emails that appear to originate from your domain, often for malicious purposes like phishing or spam. This can raise alarms about your brand's reputation and email deliverability.
While it's a serious issue, it's important to approach it with a clear strategy rather than panic. This guide outlines the immediate steps you should take and the long-term measures you can implement to protect your domain and maintain your sender reputation.
Email spoofing occurs when an email sender forges the email header to make the message appear as if it originated from a different source than it actually did. The goal is often to trick recipients into believing the email is legitimate. Attackers can manipulate the 'From' address, making it look like it came from your domain, even if they don't have access to your email account or server.
Crucially, a spoofed email doesn't mean your email account has been hacked. Attackers simply leverage the open nature of email protocols, which historically didn't strictly verify the sender's identity. This allows them to send emails that show your domain in the 'From' field, even if they are not coming from your legitimate sending infrastructure. This distinction is vital for understanding what actions are truly necessary.
The primary risk of spoofing is the damage to your domain's reputation. When recipients receive unsolicited or malicious emails appearing to be from you, they might mark them as spam, leading to your domain being placed on email blacklists (or blocklists). This can significantly impact the deliverability of your legitimate emails, causing them to land in spam folders or be rejected outright by mail servers.
What spoofing is not
Not a hack: Your email account or server has likely not been compromised. Spoofing happens outside your infrastructure.
Not always a major threat: While serious, being on minor blocklists does not always mean your legitimate emails will fail.
Not always immediate action required: Assess the impact before making drastic changes, especially to DMARC.
Your primary defense: Email authentication
The most effective way to protect your domain from being spoofed, and to mitigate the impact when it does occur, is by implementing email authentication protocols. These are critical DNS records that tell receiving mail servers whether an email claiming to be from your domain is genuinely authorized.
The three core authentication protocols are SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting, and Conformance). Together, these protocols provide a robust defense against unauthorized use of your domain. You can learn more about these in our simple guide to DMARC, SPF, and DKIM.
While SPF and DKIM define authorized senders and cryptographically sign emails, DMARC tells receiving servers what to do when an email fails these checks (e.g., quarantine, reject, or simply monitor). DMARC also provides valuable reports on email authentication failures, which are crucial for identifying spoofing attempts and improving your policy. Implementing a DMARC policy, even with a p=none policy initially, is your strongest defense.
Upon discovering your domain is being spoofed, your first instinct might be to panic, especially if you see it listed on a blocklist like Spam Eating Monkey. However, it's essential to assess the actual impact. Many blocklists are minor and don't significantly affect deliverability to major inbox providers like Google Mail or Microsoft Outlook.
Check your actual email metrics for delivery issues, complaints, bounces, or a significant drop in open rates. If these key metrics remain stable, the immediate impact might be minimal. It's often better to monitor these changes over a few days before reacting strongly to a blocklist notification from a generic checker tool, as some tools can overstate issues.
While you should ultimately move your DMARC policy towards a reject or quarantine policy to actively block spoofed emails, avoid rushing this transition during an active spoofing incident. A sudden change to reject can inadvertently block legitimate emails if your authentication isn't perfectly aligned for all your sending sources. Focus first on monitoring and understanding the scope.
Immediate actions
Monitor metrics: Check email deliverability, bounce rates, and user complaints.
Verify blocklist impact: Determine if the blocklist (or blacklist) truly affects your core audience.
Review DMARC reports: Analyze failures to understand spoofing patterns.
Don't rush
Avoid immediate DMARC reject: Rushing to a p=reject policy without proper monitoring can harm legitimate email delivery.
Don't overreact to minor blocklists: Many don't impact major inbox providers.
Strengthening your defenses
Beyond immediate responses, sustained efforts are necessary to protect your domain and maintain a strong sender reputation. The key is to ensure robust email authentication is in place and to continuously monitor your domain's health. This proactive approach helps prevent future spoofing incidents and ensures your emails consistently reach the inbox.
Regularly review your DMARC reports from Google and Yahoo to identify any unauthorized sending sources. These reports provide invaluable insights into who is sending emails using your domain, whether legitimate or not, and how they are authenticating. This data is crucial for refining your DMARC policy and identifying gaps in your email security. It also helps in understanding why your emails might be getting a DMARC verification failed error.
Finally, aim to move your DMARC policy to p=quarantine or p=reject once you are confident that all your legitimate sending sources are properly authenticated. This policy will instruct receiving mail servers to either move unauthenticated emails to the spam folder (quarantine) or block them entirely (reject), effectively stopping most spoofing attempts. This measure is a key part of protecting your domain from being spoofed and blacklisted.
Views from the trenches
Best practices
Implement DMARC: Even a p=none policy provides valuable monitoring data to identify spoofing.
Gradually enforce DMARC: Move from p=none to p=quarantine, then p=reject, monitoring reports at each stage.
Ensure all sending IPs are covered: Verify SPF and DKIM for all legitimate email sending services.
Monitor email metrics: Regularly check bounce rates, complaint rates, and open rates for anomalies.
Common pitfalls
Overreacting to minor blocklists: Not all blocklists significantly impact deliverability to major providers.
Rushing DMARC to reject: This can inadvertently block legitimate emails if not all senders are authenticated.
Ignoring DMARC reports: These reports are crucial for identifying spoofing and authentication issues.
Assuming a hack: Spoofing doesn't always mean your systems were breached.
Expert tips
Use DMARC monitoring tools to simplify report analysis and quickly identify spoofing sources.
Communicate internally about email security best practices to prevent accidental compromises.
Regularly review your domain's authentication records for correct configuration and alignment.
Segment your sending to isolate potential issues and easier troubleshooting.
Expert view
Expert from Email Geeks says that you should not worry too much if your domain is being spoofed. Your mail will not be blocked anywhere reputable, and many blacklists are run with unrealistic policies, so they will not impact your delivery rates.
October 14, 2021 - Email Geeks
Expert view
Expert from Email Geeks says that DMARC won't really affect your delivery much and you should not be messing with it while focused on something else or while making other changes.
October 14, 2021 - Email Geeks
Maintaining your domain's integrity
While email spoofing can be distressing, it's a manageable issue with the right approach. Your first line of defense involves robust email authentication, specifically DMARC, SPF, and DKIM. These protocols are essential for verifying the legitimacy of emails sent from your domain and preventing unauthorized parties from impersonating you.
By understanding that spoofing does not necessarily mean your account is compromised and by focusing on monitoring your deliverability metrics, you can avoid unnecessary panic. Implement a phased DMARC policy enforcement and continuously analyze your DMARC reports. Taking these steps will mitigate damage and prevent future occurrences, ensuring your domain's reputation remains strong and your emails consistently reach their intended recipients.
Google Mail or 
Microsoft Outlook.
