How to prevent Gmail phishing warnings for internal emails with shortened links or shared sender names?

Key findings

• URL shorteners: Generic URL shorteners (like goo.gl or Bit.ly) are frequently flagged by Gmail because they are commonly exploited in phishing attempts to hide the true destination of a link. This is a primary trigger for phishing warnings.Shared sender names: When multiple individuals send emails from a single shared address (e.g., people@yourdomain.com) but use different display names, Gmail's advanced phishing protection can interpret this as suspicious activity. This is because it looks for inconsistencies that might indicate identity spoofing.Internal email scrutiny: Gmail does not exempt internal organizational emails from its security scans. All messages are subject to pre-delivery scanning for phishing and spam indicators, regardless of the sender's domain (even if it's your own).Domain reputation: The overall reputation of your sending domain plays a significant role. A low or questionable domain reputation can exacerbate the impact of other minor triggers.
• Inconsistent warnings: Phishing warnings might not affect all recipients or all senders using the shared address equally, suggesting that recipient-specific factors or variations in content may also play a role.

Key considerations

• Avoid generic URL shorteners: Wherever possible, use the full, original URL. If shortening is necessary for internal communication, consider using a branded URL shortener (e.g., go.yourdomain.com/link) to maintain trust and transparency.
• Standardize sender identity: When using shared mailboxes, ensure consistent display names or clearly indicate the individual sender within the shared context (e.g., "John Smith via People Team").
• Review external links: Thoroughly check any third-party URLs included in your emails, even those from trusted services like Google Forms. Ensure they are not compromised or associated with past abuse.
• Monitor Gmail warnings: Pay close attention to Gmail's 'dangerous message' alerts and use Google Workspace (formerly G Suite) admin tools to investigate such incidents. These tools can provide insights into why messages are flagged.
• Educate internal users: Inform your team members about common triggers for phishing warnings and best practices for sending internal emails, especially concerning links and sender display names.

Key opinions

• URL shortener risk: Many marketers quickly identify generic URL shorteners as a primary culprit for phishing warnings, noting that Google's systems are highly sensitive to them due to past abuse.
• Google Form links: Even links to seemingly innocuous Google services like Google Forms can trigger warnings if they are sent via a shortened URL, demonstrating the strictness of Gmail's link analysis.
• Sender name inconsistency: Using a single email address with multiple distinct 'From' names (e.g., an individual's name for a shared team inbox) can be a red flag for Google's advanced phishing protection.
• ESP vs. direct sending: Some marketers distinguish between emails sent via an Email Service Provider (ESP), which often handle tracking links carefully, and those sent directly from a shared mailbox, where the sender has less control over link formatting.
• Beyond tracking links: Initial suspicions often fall on tracking links, but marketers quickly pivot to other potential issues like general URL shorteners when tracking links are ruled out.

Key considerations

• Use full URLs: The most straightforward solution is to use the full, unshortened URL for any links in internal emails. This removes ambiguity for Gmail's filters.
• Branded short links: If a short URL is absolutely necessary, marketers recommend using a branded shortener where the shortened domain is your own (e.g., go.yourcompany.com/xyz). This helps build trust and demonstrates control over the link.
• Consistent sender display: When using shared inboxes, try to maintain a consistent sender display name or clearly qualify it (e.g., "People Team" or "[Individual Name] via People Team").
• Check all links: Marketers advise meticulously checking every link in an email, even if it's to an internal form, to identify any hidden shorteners or redirects.
• Leverage DMARC and authentication: Ensuring robust email authentication like SPF, DKIM, and DMARC can build domain trust, though it might not fully override issues with problematic link types.

Key opinions

• Shortened URLs are dangerous: Experts universally agree that generic URL shorteners are a major red flag for major mailbox providers like Gmail due to their historical use in malware and phishing campaigns.
• Behavioral analysis: Gmail's filters don't just look at static indicators, but also analyze sender behavior, recipient engagement, and historical patterns associated with domains and IP addresses. Inconsistent sender display names for a single address can be flagged as behavioral anomalies.
• Brand reputation matters: A strong brand and domain reputation can mitigate some risks, but even well-regarded senders can trigger warnings if they employ practices that mimic common phishing tactics.
• Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM): Proper implementation of SPF and DKIM helps authenticate the sender but does not prevent content-based or behavioral flags related to links or sender display names.
• DMARC alignment: A robust DMARC policy can further strengthen your domain's trustworthiness, making it harder for spoofers to impersonate your domain and potentially reducing the likelihood of false positives for legitimate mail.

Key considerations

• Prioritize direct links: Wherever feasible, experts advise using the full, transparent URL. This eliminates the uncertainty that comes with shortened links for Gmail's scanning systems.
• Implement DMARC rigorously: Ensure your DMARC records are correctly configured and enforced, especially for internal domains. This helps Gmail trust your domain and differentiate legitimate internal mail from spoofing attempts.
• Consistent 'From' addresses: For shared inboxes, maintain a consistent From name across all senders or use distinct aliases that clearly indicate the individual sending from the shared account. This reduces signals of potential impersonation.
• Monitor blocklists: Regularly check if your domain or IP is listed on any email blocklists or blacklists, as this can severely impact deliverability and increase the likelihood of phishing warnings.
• Content review: Conduct periodic reviews of internal email content to ensure it does not contain phrases, images, or link structures that are commonly associated with phishing or spam.

Key findings

• URL shortening risks: Security documentation often warns that URL shorteners are a common technique used in phishing attacks to mask malicious links. This inherent risk leads email providers to treat such links with suspicion.
• Sender name spoofing: Documentation on phishing identifies sender name spoofing as a primary tactic. Inconsistencies between the 'From' name and the underlying email address, especially for internal domains, can trigger warnings.
• Advanced threat detection: Mailbox providers employ advanced threat detection systems, including machine learning, that analyze a wide range of signals beyond basic authentication to identify and flag suspicious emails.
• Email authentication importance: Official guidelines emphasize SPF, DKIM, and DMARC as fundamental for verifying sender legitimacy and protecting against email impersonation, which indirectly helps prevent phishing warnings by establishing domain trust.
• User education: Many security resources advise organizations to educate employees on how to recognize phishing attempts, including checking email addresses closely and being wary of shortened or suspicious links.

Key considerations

• Use fully qualified domain names (FQDNs): Whenever linking to internal or external resources, use the full, clear URL. Avoid any form of generic URL shortening that might obscure the link's true destination.
• Adhere to DMARC standards: Implement and enforce a DMARC policy with a p=quarantine or p=reject policy to ensure that unauthorized emails using your domain are blocked or quarantined, which enhances trust with receiving mail servers.
• Standardize 'From' header practices: For shared internal email addresses, ensure consistency in how the 'From' name is displayed. If individuals must be identified, use a format that clearly indicates it's from the shared account, minimizing ambiguity.
• Enable Google Workspace security features: For organizations using Google Workspace, configure and utilize advanced phishing and malware protection settings to enhance detection capabilities for internal emails. Pre-delivery message scanning is a key feature.
• Continuous monitoring: Regularly review Gmail Postmaster Tools for insights into your sending reputation and potential deliverability issues.