Cloud-hosted security provider GreatHorn, which offers tools to shield enterprises from email attacks, today announced a $13 million funding round co-led by RRE Ventures and .406 Ventures, with participation from existing investors Techstars Ventures, V1.VC, and Uncork Capital. The fresh capital follows a $6.3 million seed round in June 2017 and brings the company’s total raised to over $19 million.

“With a fast-growing customer base and track record of best-in-class detection and innovation for today’s cloud-based email platforms, GreatHorn has changed the way the industry talks about email security,” said CEO Kevin O’Brien, adding that last year marked the company’s third consecutive year of triple-digit revenue growth. “As we continue to meet customer demand and drive the market, we remain fundamentally interested in redefining email as a secure system for all users and ensuring that organizations who have adopted cloud email platforms are not relying on outdated perimeter controls or simple user education to protect their most critical assets.”

GreatHorn’s products connect directly to Office 365 and G Suite environments, and they don’t require topology modifications or DNS editing. Each combines adaptive threat detection, contextualized user engagement, and incident response in a single suite, with the aim of “return[ing] trust to the inbox” and “time to information security teams,” according to O’Brien.

GreatHorn’s out-of-the-box dynamic threat detection toolset not only proactively recognizes email-borne threats, including malware and phishing attacks, it learns to differentiate these from organization-specific legitimate communications by considering millions of threat vectors. For instance, it takes into account the strength of a sender’s relationship to the recipient, as well as spoofing likelihood for display names and domain lookalikes. Moreover, it performs analysis based on keywords, attachments, and URLs and messaging patterns unique to users and specific teams, and it weighs technical fingerprints — such as sending IP and header information — in making final determinations.

Meanwhile, GreatHorn’s Reporter feature provides visibility into senders’ trustworthiness by warning against emerging and ongoing threats. It autonomously evaluates the risk of every link embedded within a given email, and it enables users to quickly report phishing attempts, remove spam, or create block lists targeting bad actors.

As for GreatHorn’s automated response component, it scans and removes dangerous emails sitting in mailboxes while protecting against credential theft with sandboxed URLs and automatic page blocking. Better still, it fully integrates with a bespoke audit dashboard, allowing admins to perform full click-tracking for suspicious and malicious URLs and to narrow down things like which users clicked through to problematic destination pages at which times.

“RRE Ventures invests in passionate and tenacious teams that are building category-defining businesses,” said RRE Ventures general partner Raju Rishi. “Despite decades of experience and billions of dollars spent, the email security industry is no closer to making email safe for businesses. By rethinking how we approach email security, GreatHorn has delivered a platform that comprehensively protects enterprises against the rising sophistication of today’s threats. We’re excited to support GreatHorn as the company continues to build upon its current innovation and grow in the enterprise space.”

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