Sonatype Firewall Extends Malicious Package Protection

New Sonatype research finds only 9% of brandjacking malware relies on typosquatting alone, as attackers use trusted-looking package names to slip past developer workflows and steal credentials

Fulton, Md. – May 27, 2026 – Sonatype®, the control plane for agentic software development, today expanded Sonatype Firewall protections to help organizations block malicious open source packages before they enter any repository environment, including third-party repositories and mixed repository environments. With Firewall, enterprises have a protected front door between developers and AI coding assistants and the public registries they depend on.

Sonatype also unveiled a study of more than 4,300 malicious open source packages, observing that naming conventions and workflow familiarity are being abused to create a blind spot at the moment a developer adds a dependency or updates a lockfile. Key findings include:

• Sophisticated attackers have moved beyond typosquatting: In 91% of cases, sophisticated naming variants such as prefix-addition, version mimicry, and embedding, are used to infiltrate developer environments instead of traditional misspellings.
• Data and credential theft is the primary objective: Nearly three-quarters (74%) of the analyzed malicious packages were specifically designed to silently exfiltrate developer credentials, API keys, and environment variables to facilitate broader system compromise.
• Organized campaigns are heavily targeting popular frameworks: Attackers have industrialized their methods, with nearly 150 distinct campaign families identified. They specifically zero in on modular ecosystems like React and ESLint where deceptive add-ons easily blend in.
• Plausible deception easily bypasses traditional security controls: By convincingly mimicking legitimate extensions rather than relying on spelling errors, these packages evade standard spelling-based checks, meaning a single compromised developer machine can quickly escalate into a large-scale breach.

“Typosquatting is table stakes now. Attackers aren’t just misspelling popular package names — they’re copying the language, structure, and habits of real software ecosystems. By the time a malicious package has built a reputation, it may already be in a developer workstation,” said Brian Fox, CTO and co-founder of Sonatype and Global Maintainer of Maven Central. “Developers and AI agents need safer defaults, not more dashboards. The winning model is to approve, block, guide, and remediate when a component is chosen — not after bad code is already in the build.”

Sonatype Firewall gives next-gen development teams a first line of defense by blocking malicious and suspicious packages at assembly. Today’s expansion gives organizations control before risk reaches the build, without disrupting existing repository workflows. As the steward of Maven Central and provider of Nexus Repository, Sonatype has deep visibility into how open source components are published, consumed, and propagated across modern software development. That visibility, including two decades of open source intelligence, helps organizations make better decisions at the source.

Expanded Sonatype Firewall protections are available for any repository. To read the full study, Beyond Typosquatting Attacks: How Threat Actors Use Naming Variants to Steal Developer Data, visit: https://www.sonatype.com/resources/research/beyond-typosquatting-attacks.

About Sonatype

Sonatype gives enterprises control over what goes into software, before it becomes production risk. As development accelerates with open source, AI assistants, and agentic workflows, Sonatype helps developers and security teams choose what is safe, block what is dangerous, and fix what matters without slowing innovation. As the steward of Maven Central and provider of Nexus Repository, Sonatype has unmatched visibility into how open source components are published, consumed, and propagated. Its platform protects, guides, and governs software assembly across the SDLC — helping organizations stop malicious packages, make better dependency decisions, remediate faster, and prove what’s inside every application. To learn more about Sonatype, please visit www.sonatype.com.