Pierluigi Paganini November 16, 2021

Maintainers of the npm package manager for the JavaScript programming language disclosed multiple flaws that were recently addressed.

GitHub disclosed two major vulnerabilities in the npm that have been already addressed.

The first vulnerability can be exploited by an attacker to publish new versions of any npm package using an account without proper authorization. The flaw was reported by Kajetan Grzybowski (DrBrix) and Maciej Piechota (haqpl) to GitHub through its bug bounty program on November 2.

“We determined that this vulnerability was due to inconsistent authorization checks and validation of data across several microservices that handle requests to the npm registry. In this architecture, the authorization service was properly validating user authorization to packages based on data passed in request URL paths. However, the service that performs underlying updates to the registry data determined which package to publish based on the contents of the uploaded package file. This discrepancy provided an avenue by which requests to publish new versions of a package would be authorized for one package but would actually be performed for a different, and potentially unauthorized, package.” wrote GitHub security chief Mike Hanley.

The company addressed the flaw in a few hours by ensuring consistency across both the publishing service and authorization service, in this way the same package is being used for both authorization and publishing.

GitHub is not able to determine if the flaw has ever been exploited in attacks.

“This vulnerability existed in the npm registry beyond the timeframe for which we have telemetry to determine whether it has ever been exploited maliciously. However, we can say with high confidence that this vulnerability has not been exploited maliciously during the timeframe for which we have available telemetry, which goes back to September 2020.” added Haley.

The second flaw was discovered by GitHub’s security team on October 26, and was caused by routine maintenance of one of the project’s publicly available npm services. 

The issue is a data leak on the npmjs’ replication server, which was caused by ‘routine maintenance.’ The leak exposed a list of names of private npm packages during the maintenance window. The content of the packages is not exposed in the same timeframe.

“First, on October 26 we identified an issue caused by routine maintenance of one of our publicly available npm services. During maintenance on the database that powers the public npm replica at replicate.npmjs.com, records were created that could expose the names of private packages,” added Hanley. “This briefly allowed consumers of replicate.npmjs.com to potentially identify the names of private packages due to records published in the public changes feed. No other information, including the content of these private packages, was accessible at any time. Package names in the format of @owner/package for private packages created prior to October 20 were exposed between October 21 13:12:10Z UTC and October 29 15:51:00Z UTC.”

The flaw was addressed on October 29, the company also deleted from the npm’s replication database all records containing private package names.

GitHub is working to improve the security of the npm registry, it plans to introduce two-factor authentication (2FA) authentication for maintainers and admins of popular packages on the repository, The new feature will be implemented starting with a list of top packages in the first quarter of 2022. 

“These investments include the requirement of two-factor authentication (2FA) during authentication for maintainers and admins of popular packages on npm, starting with a cohort of top packages in the first quarter of 2022. Read on to learn more.” Hanley concluded.

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Pierluigi Paganini

(SecurityAffairs – hacking, npm)

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