chai-as-tokenizednpm
Advisory published Updated
chai-as-tokenized is a confirmed malicious npm package (MAL-2026-5902) that opens a backdoor for remote access (malicious version 7.2.3). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in chai-as-tokenized (npm)
What this malware does
Package name impersonates chai-as-promised, and the README is a copy of pino's documentation, but the actual code is a remote-code-execution dropper. The exported middleware (advertised as chai.use(chaiAsTokenized)) spawns lib/initializeCaller.js as a detached node child with stdio:'ignore' and child.unref(), hiding output and surviving parent exit. The child shadows the process global with a fake object whose env values are base64 strings, atob-decodes them to obtain https://amethyst-lorrin-26.tiiny.site/index.json and the header x-secret-key: _, fetches JSON from that anonymous tiiny.site endpoint, and passes the response's cookie field to new Function.constructor('require', response) invoked with the live require — granting the remote, attacker-controlled host arbitrary code execution inside the consuming process with full module access. Combined signals: name-impersonation of a popular chai plugin, README mismatch with shipped code, base64-obfuscated C2 URL, anonymous static-file host (not a publisher domain), detached-and-silenced child spawn, and remote response evaluated as JavaScript.
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-tokenized (version 7.2.3).
If you installed it — respond
chai-as-tokenized 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-tokenized 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-tokenized-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.