chai-as-tunednpm
Advisory published Updated
chai-as-tuned is a confirmed malicious npm package (MAL-2026-4513) that opens a backdoor for remote access (malicious version 7.2.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in chai-as-tuned (npm)
What this malware does
Package name chai-as-tuned impersonates chai-as-promised and ships a README copy-pasted from the unrelated pino project (npm/CI badges point at pinojs/pino). The advertised middleware in index.js spawns lib/initializeCaller.js as a detached node process whenever the exported function is invoked. That script constructs a fake local process object whose DEV_API_KEY is a base64 literal decoding to https://aqua-margit-84.tiiny.site/index.json (tiiny.site is an anonymous static-hosting service), GETs the JSON via axios, and passes the response.cookie field to new Function.constructor('require', response)(require) — executing attacker-controlled JavaScript with full Node privileges and access to the host's require. The combination of name-confusion, copied README, base64-hidden C2 URL, Function.constructor indirection to defeat static review, and remote-fetch-and-eval is an unambiguous supply-chain attack: any consumer who follows the README and uses the main export will execute whatever code the attacker serves at runtime.
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for chai-as-tuned (version 7.2.2).
If you installed it — respond
chai-as-tuned establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If chai-as-tuned was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks chai-as-tuned-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.