Chrome Extensions Vulnerability Exposes API Keys, Secrets, and Tokens

A significant security vulnerability affecting millions of Chrome extension users has been discovered, revealing widespread exposure of sensitive API keys, secrets, and authentication tokens directly embedded in extension code. This critical flaw stems from developers hardcoding credentials into their JavaScript files, making these secrets accessible to anyone who inspects the extension packages. The vulnerability affects […] The post Chrome Extensions Vulnerability Exposes API Keys, Secrets, and Tokens appeared first on Cyber Security News.

Jun 6, 2025 - 18:10

Chrome Extensions Vulnerability Exposes API Keys, Secrets, and Tokens

A significant security vulnerability affecting millions of Chrome extension users has been discovered, revealing widespread exposure of sensitive API keys, secrets, and authentication tokens directly embedded in extension code.

This critical flaw stems from developers hardcoding credentials into their JavaScript files, making these secrets accessible to anyone who inspects the extension packages.

The vulnerability affects popular extensions with millions of combined users, potentially exposing cloud services, analytics platforms, and other third-party integrations to unauthorized access and abuse.

The security oversight represents one of the most fundamental mistakes in modern software development, where sensitive authentication materials are stored in plain text within client-side code.

Once Chrome extensions are published to the Web Store, their source code becomes readily available for inspection, effectively broadcasting these credentials to potential attackers.

The implications extend far beyond simple data exposure, as malicious actors can leverage these credentials to spam analytics services, incur unauthorized cloud computing costs, upload malicious content, or gain broader access to connected services depending on the permissions associated with each compromised key.

Symantec researchers identified this widespread vulnerability while conducting routine security assessments of popular browser extensions, uncovering a pattern of poor credential management practices across multiple high-profile extensions.

The discovery highlights a systemic issue in extension development practices, where convenience often supersedes security considerations.

The affected extensions collectively serve over 15 million users, making this one of the largest credential exposure incidents in recent browser extension history.

The vulnerability’s impact varies significantly depending on the type and scope of exposed credentials, ranging from corrupted analytics data to potential financial losses for extension developers whose cloud services become targets for abuse.

More concerning is the possibility that attackers could use compromised AWS credentials or similar cloud service keys to pivot into broader infrastructure, potentially accessing databases, file storage systems, or other connected resources if the credentials possess elevated permissions.

Technical Analysis of Credential Exposure Patterns

The exposed credentials follow distinct patterns across different extension categories, with analytics keys, cloud storage credentials, and speech recognition API tokens representing the most common vulnerabilities.

In the case of Avast Online Security & Privacy and AVG Online Security extensions, hardcoded Google Analytics 4 API secrets appear directly in JavaScript variables.

Code snippets showing hardcoded Google Analytics 4 (GA4) API secrets (Source – Security)

The code snippet var GA4_API_SECRET = "2y-Q"; demonstrates how these secrets are appended to analytics URLs, enabling attackers to flood GA4 endpoints with fraudulent events and corrupt metrics data.

Similarly, the Equatio – Math Made Digital extension exposes Azure API keys for speech recognition services through window.equatioAzureApiKey = "48!3";.

This exposure allows malicious users to consume the developer’s Azure subscription resources, potentially resulting in significant unexpected costs.

Exposed AWS access key (Source – Security)

The most severe cases involve AWS access keys found in screenshot applications, where the exposed credentials AWSAccessKeyId: "AKIA" could enable attackers to upload malicious content to S3 buckets or access other AWS services if the credentials possess broader permissions.

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