Rein Security Emerges From Stealth With $8M, Bringing Inside-Out AppSec Approach

"While considering their next steps, Bar Efrat asked Rubin, 'Why have you always been able to hack web servers so easily?' Rubin's reply ultimately comes down to a visibility gap into the context of an application in production. Most existing AppSec tools stop at code scanning and pre-production testing. This surfaces issues but fails to show how applications actually behave once they are in production."

"The two decided to tackle this issue, and developed a patent-pending platform technology that promises real-time context and protection inside application production environments. The reaction speed available from within the app, in detecting and responding to something that shouldn't be happening, will become increasingly important and urgent as the speed and scale of AI-assisted and vibe-coded malicious attacks continues to grow."

"Bar Efrat explains the current difficulties in relation to an agentic AI application. Firstly, traditional guardrails around prompts are hard. The prompt could be a one-liner, a document or a picture, all possibly with hidden malicious prompt content. A bigger problem is that the application itself is non-deterministic; by definition it is probabilistic. "The only way to provide security here is to be as"

Rein Security emerged from stealth with $8 million in funding and backing from Glilot Capital. The company is co-headquartered in Tel Aviv and New York City and was founded by Matan Bar Efrat (CEO) and Netanel Rubin (CTO) in 2024. Both founders have deep backgrounds in application security and identified a visibility gap in how applications behave in production versus pre-production scans. Rein developed a patent-pending platform that provides real-time context and protection inside production applications, enabling rapid detection and response. The approach targets growing risks from AI-assisted and non-deterministic agentic applications and hidden malicious prompts.

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