Browser extension security tools, compared

Why assess browser extensions?

With host permissions, an extension can read and change the pages you visit, including cookies, forms, and requests. That access is legitimate for real tools and dangerous in the wrong hands.

The hardest case is the poisoned update: an extension ships clean, earns installs, and adds malicious behavior in a later release. Assessing an extension once at install does not cover it, which is why automated, per-version analysis matters.

Extuno

Extuno analyzes browser and IDE extensions (Chrome, Firefox, VS Code, JetBrains, Eclipse, Discord) and developer packages (npm, PyPI) with 1100+ static rules, a dynamic micro-VM sandbox, AI analysis, and cross-version diffing. Every finding carries the file, line, evidence, and recommended action. It offers free scan credits and a free browser companion that scans installed extensions and blocks malicious sites.

Static extension scanners

Automated extension scanners read an extension from its store and score it on signals like permissions, vulnerable libraries, a weak Content-Security-Policy, and store metadata. They give a fast read on an extension. Some well-known scanners in this category have been discontinued and are no longer maintained, so check whether a tool is still active before relying on it.

Extension risk-scoring platforms

AI-driven risk-scoring platforms score browser extensions and connected apps on permissions, behavior, publisher reputation, and data flows, usually on a 0 to 100 scale. They are commonly used for SaaS and workspace governance, often with a free checker and a paid platform.

Manual review

Reading the manifest and source by hand is always an option and is useful for one-off judgment calls. It does not scale to every version of every extension, which is the gap automated tools fill.