Tenable acquires Sam Altman-backed Apex for over $105 million to boost AI security

American cybersecurity company Tenable is acquiring Israeli startup Apex Security for over $105 million, Calcalist has learned. The acquisition aims to expand Tenable’s exposure management platform into the field of artificial intelligence, today’s most significant technological revolution and the fastest-growing threat vector in the cybersecurity world.

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After evaluating companies in the AI security space, Tenable identified Apex as the market leader in the field. Despite having raised just $8.6 million, Apex is being acquired for more than $105 million, an impressive outcome for a company founded only two years ago. Apex's Seed round was co-led by Sequoia Capital and Index Ventures, with participation from angel investors, most notably OpenAI CEO Sam Altman and Clem Delangue (CEO of Hugging Face).

The company was founded in 2023 by CEO Matan Derman and CPO Tomer Avni. The duo met during their Unit 8200 service where they served as Lieutenant Colonel and Captain, respectively. Both hold Master’s degrees from Stanford and Harvard and Apex already caters to various Fortune 500 companies as clients.

Apex has built a security platform that provides organizations with comprehensive visibility of their AI activity. This allows them to define how AI is used across the company and enforce security policies accordingly. Its platform can detect violations of the security standards of the company or industry, and detect and respond to AI attacks so that companies can leverage AI technologies to avoid data leaks, malicious data injection, privacy and legal violations, or cyberattacks.

This marks Tenable’s sixth acquisition in Israel. The deal is also intended to strengthen the company’s executive presence in the country.

Tenable is an American cybersecurity company specializing in cyber exposure management. It was founded in 2002 and is headquartered in Columbia, Maryland. The company is best known for developing Nessus, one of the most widely used vulnerability scanners in the world. Tenable was founded by Ronald Gula, Jack Huffard, and Renaud Deraison, who had already developed Nessus back in 1998.

Tenable’s previous acquisitions in Israel include:

Indegy – An Israeli cybersecurity startup specializing in securing industrial control systems (ICS) and operational technologies (OT). The company developed an advanced platform that provides real-time visibility, control, and security for industrial networks, aiming to protect critical infrastructure such as manufacturing, energy, water, and pharmaceuticals from cyber threats, human error, and insider risks. Founded in 2014, Indegy was acquired by Tenable in 2019 for $78 million.

Cymptom - An Israeli startup focused on attack path management in cybersecurity. It developed an agentless platform that maps potential attack paths within organizations and helps identify critical vulnerabilities before they can be exploited by attackers. Founded in 2019, Cymptom was acquired by Tenable in 2022 for an estimated $23 million.

Ermetic - An Israeli startup specializing in cloud infrastructure security. It developed a sophisticated platform that integrates cloud infrastructure entitlement management (CIEM) with cloud security posture management (CSPM), offering a comprehensive solution for organizations operating in multi-cloud environments such as AWS, Azure, and Google Cloud. Ermetic was acquired by Tenable in 2023 for $265 million.

Eureka - An Israeli startup focused on data security posture management (DSPM) in the cloud. The company developed a platform that enables organizations to identify, map, and protect sensitive data across multi-cloud environments, providing full visibility into data locations, access configurations, and potential risks. Founded in 2021, Eureka was acquired by Tenable in 2024 for $29.6 million.

Vulcan - An Israeli startup specializing in cyber risk management and automated vulnerability remediation. The company developed a platform that allows organizations to identify, prioritize, and remediate vulnerabilities automatically, integrating with existing security tools. Founded in 2018, Vulcan was acquired by Tenable in 2025 for $150 million.

In recent years, Tenable has also made several acquisitions outside Israel as part of its effort to expand its cybersecurity capabilities. In 2016, Tenable acquired FlawCheck, a U.S.-based container security company, for an undisclosed amount. In 2021, it acquired Alsid, a French company specializing in Active Directory security, for approximately $98 million, and Accurics, a U.S. company that developed infrastructure-as-code (IaC) security solutions, for about $160 million. In 2022, it acquired Bit Discovery, a U.S.-based provider of external attack surface management (EASM) solutions, for roughly $45 million.

“The AI attack surface is deeply intertwined with everything else organizations are already securing. Treating it as part of exposure management is the most strategic approach. We’re excited to join forces with Tenable to help customers manage AI risk in context - not as a silo, but as part of their broader environment,” said Derman.