How to Recover Your Email Reputation After a Domain Hack (And Prevent It from Happening Again)

Your domain just got hacked.
It’s frustrating. It’s overwhelming. And for anyone managing email campaigns, it’s an outright nightmare. The moment attackers start spoofing your domain for phishing or spam, your sender reputation can take a nosedive—leading to email delivery issues, blacklisting, and massive trust erosion.

The good news? You can stop the damage, restore control, and come back stronger—with a security-first email marketing approach.

Here’s a step-by-step guide on what to do right now, and how cmercury’s deliverability infrastructure can help prevent future email disasters.

1. Lock Down Your DMARC Policy: Set to p=reject Immediately

Start with your DMARC settings. This is the frontline defense against unauthorized senders using your domain.

Update your DNS record to a strict DMARC policy:
v=DMARC1; p=reject; rua=mailto:your-report@yourdomain.com; ruf=mailto:forensics@yourdomain.com; fo=1; adkim=s; aspf=s

What this does:

• p=reject: Blocks unauthenticated emails from ever reaching inboxes.
  
• adkim=s & aspf=s: Enforces strict alignment with your DKIM and SPF settings.
  
• rua/ruf: Enables visibility through aggregate and forensic reports.
  

With cmercury, these reports are integrated into your dashboard for daily visibility, helping you catch anomalies early.

2. Audit SPF & DKIM Records (Thoroughly)

If your domain was compromised, assume nothing is safe.

✅ SPF: Limit IPs only to trusted senders. Remove unused ESPs or old servers.
✅ DKIM: If the private key was exposed, regenerate and update immediately.

cmercury supports custom SPF and DKIM configurations and can rotate DKIM keys upon request for enhanced protection.

This kind of email authentication is essential for safeguarding your sender reputation.

3. Change Every Login & API Key

Assume all credentials were seen:

• Hosting and DNS logins (e.g., GoDaddy, Cloudflare)
  
• ESP access (Amazon SES, Mailgun, cmercury)
  
• API tokens, SMTP keys, CRM integrations
  

Rotate everything. This step alone can cut off access for attackers still lurking in your infrastructure.

4. Scan Your DNS Records for Suspicious Entries

Look for:

• Unknown MX, SPF, or CNAME entries
  
• Fake DKIM selectors redirecting to attacker-controlled keys
  

If you’re a cmercury user, our onboarding and support teams can assist with secure DNS configurations and cleanup.

5. Monitor DMARC Reports Like a Hawk

You can’t fix what you can’t see.

DMARC reports show:

• Spoofing attempts (and from where)
  
• Pass/fail rates for SPF/DKIM
  
• Overall email authentication health
  

cmercury offers automated monitoring of these reports, integrated with engagement benchmarking and data hygiene audits—combining human oversight with intelligent automation.

6. Check for Blacklists & Abuse Activity

Use:

• Google Postmaster Tools
  
• MXToolbox Blacklist Check
  

If your domain is blacklisted or flagged, cmercury’s deliverability team can guide you through delisting processes and sender reputation recovery.

Recovering from email spoofing starts with identifying exactly where your reputation took the hit.

7. Add BIMI (Once You’re Clean)

Once your domain is secure, adding a BIMI (Brand Indicators for Message Identification) record allows your brand logo to appear in inboxes. This boosts trust—especially after a security event—but should only be implemented after full recovery.

8. Communicate Transparently

If email spoofing reached customers or partners, inform them. It protects your brand and limits additional fallout.

• Notify clients and partners
  
• Report the abuse to your email platform
  
• If necessary, alert local CERTs or legal teams
  

Why This Matters for Email Marketers in 2025

Your inbox placement is no longer just about good subject lines and open rates—it’s about trust, security, and authenticated delivery.

That’s where cmercury stands out.

✅ How cmercury Protects Your Email Campaigns

• 99.6% Inbox Placement Rate
  
• Prewarmed IPs with Round Robin IP Switching
  
• Engagement-Based Priority Sending
  
• ISP-Wise Throughput Planning & Volume Capping
  
• Daily Human & Tool-Based Monitoring of IP Health and Data Hygiene
  
• Smart Send Technology: Deliver to your most engaged users first, maximizing reputation signals
  

Whether you’re recovering from a hack or simply strengthening your email marketing platform, these deliverability safeguards are essential.

Final Word

SPF, DKIM, and DMARC aren’t silver bullets—but they are your strongest armor in an era of rising spoofing, phishing, and domain abuse. When combined with a platform like cmercury that prioritizes deliverability from the ground up, you get peace of mind and performance—even in the face of a crisis.Need help setting up authentication or recovering from a hit to your reputation? We’ve helped brands bounce back and build stronger email security practices. Let’s talk.