MalwarePublished 14 Jul 2026

chai-as-sets (npm) · Malicious Code

Affects chai-as-setsSource GCVE Database

Malicious package : remove chai-as-sets and rotate any secrets on hosts that installed it.

Data as of 14 Jul 2026, 09:40 UTC

Classification

Malicious package

Published to npm · OSV MAL-2026-10519

What to do

Remove chai-as-sets from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.

Affected software

Product	Affected	Fixed in
npmchai-as-sets	Affected =3.1.3	Fixed in–

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Description

The npm package chai-as-sets version 3.1.3 contains malicious code that executes upon module load. It spawns a detached child process which decodes a hardcoded URL and sends the installer's environment variables to a remote server. The server's response is executed as code with access to the package's require function, enabling arbitrary remote code execution. The package attempts to disguise itself by impersonating another library (pino).

Impact

Any system that installs and requires chai-as-sets version 3.1.3 is at risk of arbitrary remote code execution controlled by the attacker. The attacker can exfiltrate environment variables and execute arbitrary code with the privileges of the process loading the package. This can lead to full system compromise depending on the environment and privileges.

Defensive guidance

Users should immediately remove and avoid using chai-as-sets version 3.1.3. Audit dependencies for this package and replace it with a trusted alternative. Monitor for any unexpected network connections to the indicated C2 URL.

Summary

The chai-as-sets package version 3.1.3 is a malicious npm package that, when required, spawns a detached child process executing lib/initializeCaller.js. This process base64-decodes a hardcoded URL pointing to a command-and-control server and POSTs the entire process environment variables to it. The server's HTTP response body is then passed to a new Function constructor with require injected, allowing the remote server to execute arbitrary code on the host. The package masquerades as a pino-related module to evade detection. This behavior constitutes a supply chain attack via a malicious package.

References

npmjs.com/package/chai-as-sets/v/3.1.3 (opens in a new tab)

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What to do

Affected software

Description

AI analysisMachine-generated, updated 14 Jul 2026, 09:40 UTC

Technical details

References

Community reviews