Preventing brand and sender profile impersonation in emails is a critical challenge for businesses, extending beyond traditional domain spoofing. While technical email authentication protocols like DMARC are fundamental in combating direct domain abuse, they have limitations when it comes to sophisticated brand impersonation that leverages display names, reply-to addresses, or similar-looking domains (typosquatting). This type of abuse often leads to customer complaints and significant damage to brand reputation. Effective prevention requires a multi-faceted approach, combining robust technical measures with active brand monitoring, internal process improvements, and user education.
Key findings
DMARC limitations: DMARC (Domain-based Message Authentication, Reporting, and Conformance) is essential for blocking exact domain impersonations. However, it does not inherently protect against lookalike domains or situations where attackers use free email accounts while merely mimicking the sender name or brand assets.
BIMI's role: While BIMI (Brand Indicators for Message Identification) enhances brand recognition by displaying your logo next to authenticated emails, it is a reward for proper DMARC implementation, not a direct anti-impersonation tool for display name or reply-to spoofing. It relies on the underlying DMARC policy being enforced (p=quarantine or p=reject).
Reply-to headers: The 'Reply-To' header is not a protected email header. This means malicious actors can easily set a 'Reply-To' address that appears legitimate, even if the actual sending domain is different. This is a common tactic in brand impersonation.
User vigilance and education: End-users are often vulnerable to impersonation scams, making education on how to spot fraudulent emails crucial. Businesses should clearly communicate how their legitimate emails appear (e.g., presence of BIMI logo, specific domain usage).
Legal and investigative measures: Brand impersonation and falsified headers can violate copyright, trademark, and anti-spam laws like CAN-SPAM. Pursuing legal action or engaging investigative services may be necessary to identify perpetrators, though this can be expensive and challenging due to the nature of botnets and international jurisdictions.
Key considerations
Implement DMARC: Ensure your DMARC policy is set to p=quarantine or p=reject for maximum protection against direct domain spoofing. Understand the benefits of implementing DMARC to safeguard your domain.
Monitor DMARC reports: Regularly review your DMARC reports to identify sources of unauthorized email sending. This can help you understand potential spoofing attempts and even misconfigurations within your own email ecosystem. Consider how to identify and handle spoofed emails violating DMARC policies.
Educate support teams: Train your customer support team on the importance of collecting email headers from users who report impersonation attempts. This data is crucial for investigating the origin of the fraudulent emails.
Legal consultation: Consult with legal counsel regarding trademark and copyright infringement related to brand impersonation. They can advise on potential legal actions, including issuing cease and desist letters or pursuing lawsuits, if perpetrators can be identified.
Customer awareness campaigns: Proactively educate your customers on how to identify legitimate emails from your brand, emphasizing authenticated domains and brand logos (if BIMI is implemented). The FTC provides useful guidance on how to recognize and avoid phishing scams.
What email marketers say
Email marketers frequently grapple with brand impersonation, especially when it extends beyond simple domain spoofing to involve sender names and reply-to addresses. They often seek practical advice on how to mitigate the impact of such attacks, which can lead to customer confusion and tarnish brand trust. While technical solutions like DMARC are recognized as crucial, marketers emphasize the challenge of dealing with less technically sophisticated but equally damaging forms of impersonation, where the visual branding or sender name is copied.
Key opinions
BIMI's purpose: Many marketers mistakenly believe that BIMI will directly stop branding spoofing. However, it's primarily a visual indicator of authenticity for emails already protected by DMARC, designed to reassure recipients and boost brand recognition in the inbox.
Sender name vulnerability: There's a shared understanding that sender names and reply-to addresses are particularly susceptible to impersonation because they are not protected by standard email authentication protocols like DMARC. This makes them easy targets for bad actors.
Challenge with customer data: Marketers frequently encounter difficulties when their support teams cannot or will not ask for email headers, which are vital for investigating impersonation complaints and identifying the true source of fraudulent emails.
Brand reputation risk: The primary concern for marketers is the damage to brand reputation and customer trust when fake emails, even those not directly spoofing the domain, lead to complaints and confusion among their user base.
Key considerations
Educate internal teams: It is crucial to educate internal teams, especially customer support, on the critical role of email headers in investigating impersonation issues. They need clear instructions on how to obtain these headers from affected users.
Proactive brand monitoring: Marketers should actively monitor for instances of brand impersonation across various channels, including email and social media. Regularly tracking your digital presence helps identify and take down impersonators quickly. This is part of maintaining a consistent newsletter sender identity.
Enhance user communication: Clearly communicate to your audience what to expect from your official emails. Inform them about distinctive features (e.g., your logo displayed via BIMI, specific sender names like best practices for email 'from' addresses) and what red flags to look for in suspicious messages.
Legal action for compliance: In cases of severe brand impersonation that impacts customers, engaging legal teams to pursue infringers can be a necessary, albeit potentially costly, step. This may involve addressing falsified headers that violate anti-spam laws, as detailed in various resources on email spoofing and brand impersonation.
Marketer view
Marketer from Email Geeks indicates they initially hoped BIMI would directly prevent bad actors from using their sender profile information to spam people. They understood BIMI would provide a visual cue like a logo, but they weren't sure how it would stop the underlying impersonation issue.
07 Nov 2022 - Email Geeks
Marketer view
Marketer from Email Geeks explains their specific challenge involves bad actors using their sender name, reply-to name, and reply-to email address. They noted that these fraudulent emails prominently use their brand, leading to significant customer confusion and complaints.
07 Nov 2022 - Email Geeks
What the experts say
Email deliverability experts highlight that while DMARC is a robust defense against direct domain spoofing, it does not cover all forms of impersonation. They consistently point out the inherent vulnerabilities of unprotected email headers, such as 'Reply-To,' and the pervasive challenge posed by botnets. Experts emphasize the investigative nature of addressing advanced impersonation, often requiring deep technical insight and, at times, legal intervention, despite the high costs and potential for dead ends.
Key opinions
DMARC's specific role: Experts confirm that DMARC's primary function is to block exact domain impersonations, effectively preventing unauthorized use of your domain in the 'From' address. It is not designed to stop lookalike domains or brand-only spoofing.
Unprotected headers: The 'Reply-To' header is explicitly identified as an unprotected header, meaning there is no inherent email authentication mechanism that prevents its abuse for impersonation purposes.
Botnet prevalence: A significant portion of brand impersonation is attributed to large-scale botnet operations. These often lead to dead ends in investigations due to the distributed and obfuscated nature of the attacks.
Value of headers: Email headers are universally recognized by experts as the most crucial piece of information for diagnosing and addressing impersonation, as they reveal the true sending path and authentication status.
Spam trap utility: Running spam traps or collaborating with entities that do can help identify instances of impersonation, even when direct user reports are lacking. Spam traps can capture fraudulent emails that mimic your brand.
Key considerations
Header collection protocol: Establish clear protocols and provide user-friendly instructions for collecting email headers from complainants. This critical step enables effective investigation and potential action against the perpetrators. You can refer to guides on how to identify phishing emails.
Legal pathways: While costly, legal involvement can be necessary to pursue copyright and trademark infringements. Legal teams can mandate support to collect headers, which can then be used to approach sending platforms to shut down malicious campaigns, helping to mitigate damage from email spoofing.
Partner monitoring: If impersonation is suspected to originate from partners, subscribe to their mailing lists and monitor their email practices. This allows for proactive detection and resolution of unauthorized brand usage.
Domain reputation and blocklists: Even if impersonation emails aren't directly spoofing your domain, they can still harm your overall domain reputation if they are frequently reported as spam. Monitoring your email domain reputation and checking for blocklist placements (even those caused by impersonators using similar-looking domains) is vital.
Expert view
Expert from Email Geeks states definitively that BIMI will not stop bad actors from using a sender's profile information to send spam. They clarify that this particular task falls under the purview of DMARC, which is designed to prevent unauthorized domain usage.
07 Nov 2022 - Email Geeks
Expert view
Expert from Word to the Wise confirms that the 'Reply-To' header is not protected by email authentication standards. This means there is no technical measure a sender can implement to prevent a malicious party from forging this specific header, making it a common vector for impersonation.
07 Nov 2022 - Word to the Wise
What the documentation says
Official documentation and industry standards (like RFCs) provide the technical backbone for email authentication, which is the primary defense against impersonation. They define how protocols such as SPF, DKIM, and DMARC should be implemented to verify sender authenticity. While these documents detail the mechanisms to prevent domain spoofing, they also implicitly highlight areas where brand impersonation can still occur, particularly concerning human-readable headers not covered by cryptographic signing.
Key findings
DMARC enforcement: DMARC (RFC 7489) mandates that for emails to pass authentication, both SPF and DKIM must align with the From domain, allowing receiving mail servers to apply policies (none, quarantine, reject) against unauthenticated messages. This is the cornerstone of preventing domain spoofing.
SPF and DKIM roles: SPF (Sender Policy Framework, RFC 7208) authorizes sending IPs, while DKIM (DomainKeys Identified Mail, RFC 6376) provides cryptographic signatures to verify message integrity and sender domain. Both are foundational for DMARC and prevent direct domain forgery.
BIMI requirements: BIMI (Brand Indicators for Message Identification) requires an enforced DMARC policy (p=quarantine or p=reject) and a verified mark certificate (VMC) for logo display. It visualizes brand authenticity rather than acting as a standalone anti-impersonation protocol.
Header vulnerabilities: Email headers outside of the authenticated From address, such as the display name (RFC 5322 From header) and Reply-To, are generally not cryptographically protected by these protocols, leaving them open to easy manipulation for brand impersonation.
Key considerations
Implement DMARC at enforcement: The most effective technical measure against domain impersonation is to move your DMARC policy to p=quarantine or p=reject. This ensures that unauthenticated emails purporting to be from your domain are either quarantined or rejected by receiving mail servers, as discussed in DMARC policy transitions.
Align all sending sources: Ensure that all legitimate email sending sources are correctly configured with SPF and DKIM and pass DMARC alignment. Any misconfigured source could inadvertently cause legitimate emails to fail authentication, leading to delivery issues. A simple guide to DMARC, SPF, and DKIM is available.
Monitor for domain variants: While DMARC protects your primary domain, actively monitor for typosquatting (e.g., exampl.com). These lookalike domains are often used in brand impersonation to trick unsuspecting recipients.
Understand header manipulation: Be aware that email display names and reply-to addresses are easily manipulated by attackers. Implement recipient-side awareness campaigns to instruct users on how to check full email headers, which will reveal the true sending domain. For more technical insights, refer to RFC 5322 for email message format.
Technical article
Documentation from DMARC.org explains that DMARC enables domain owners to specify what actions recipient email servers should take when an email fails DMARC authentication. This includes rejecting or quarantining messages that falsely claim to be from a domain, thereby preventing unauthorized use of the primary domain.
10 Jan 2024 - DMARC.org
Technical article
Documentation from BIMI.org outlines that BIMI builds upon DMARC. For a brand's logo to appear next to their emails in supported inboxes, the domain must have a DMARC policy set to enforcement (quarantine or reject). This indicates that BIMI serves as a visual trust signal, contingent on strong underlying authentication.