Cisco Secure Email Threat Defense is a commercial email security platforms solution by Cisco. Sublime Security Sublime Rules is a free detection engineering solution by Sublime Security. Features, integrations, deployment and the company behind each one, side by side.
What our shortlists say about the one we picked.
Best for: Cisco shops wanting Talos-backed filtering
It is on the list as a Microsoft 365 product that can grow with you: you start in API mode and add the inline gateway later, from the same console. That suits a team that already runs Cisco security. Check fit first if you run Google Workspace or your own mail servers, because the product is built for Microsoft 365.
From Best Email Security Solutions for Business, Fall 2026
Reviewed by Nika (Nikoloz) Kokhreidze.
Email threat protection for Microsoft 365 with advanced detection capabilities
Open-source detection rules for email attacks like BEC, phishing, and malware
See more solutions in this category, or build a security stack from your picks.
Based on what each listing shows: deployment, company size, price and open source.
Cisco Secure Email Threat Defense fits if you want a cloud product.
Sublime Security Sublime Rules fits if you need to run it on your own servers, you are a startup, you need a free product and you want an open-source product.
Common questions when comparing Cisco Secure Email Threat Defense vs Sublime Security Sublime Rules for email security platforms.
Cisco Secure Email Threat Defense: Email threat protection for Microsoft 365 with advanced detection capabilities, built by Cisco.
Sublime Security Sublime Rules: Open-source detection rules for email attacks like BEC, phishing, and malware, built by Sublime Security.
The table above shows where their features, integrations, deployment and company size fit differ.
Cisco Secure Email Threat Defense is made by Cisco. Sublime Security Sublime Rules is open-source. The vendor behind a product decides its roadmap, support, and longevity, so check each company's profile before you commit.
In part. Cisco Secure Email Threat Defense and Sublime Security Sublime Rules are not in the same category on CybersecTools. Key differences: Cisco Secure Email Threat Defense is Commercial while Sublime Security Sublime Rules is Free. Use the table above to see where features, deployment and company size fit differ.
Need the answer fast? Best Email Security Solutions for Business picks Proofpoint Core Email Protection, Microsoft Defender for Office 365, Mimecast Advanced Email Security and 4 more.See the shortlist
