chai-utils-testnpm
chai-utils-test is a confirmed malicious npm package (MAL-2026-5748) that opens a backdoor for remote access (malicious versions 4.5.0, 4.5.1, 4.5.2…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in chai-utils-test (npm)
What this malware does
Package name 'chai-utils-test' impersonates the popular 'chai' assertion library and ships a cloned chai source tree. The declared main (index.js) calls a top-level launcher that spawns node lib/chai/utils/assertion.js as a detached child process with stdio:'ignore' and child.unref(), so the dropper survives the parent and produces no visible output. The child uses axios to GET https://statecheck.ddns.net/api/scanner.js (a dynamic-DNS host) with a base64-encoded key=YWRtaW46c2VjcmV0MTIz query parameter (likely a server-side gate for staged payload delivery), then runs the response body via new Function('require', s)(require) — granting the attacker-served code full Node require() access. The package also pre-installs a global.atob polyfill backed by Buffer.from(x,'base64').toString('utf8') in preparation for the fetched payload. Net effect: any developer or CI job that requires/imports this package executes attacker-controlled code from a mutable remote endpoint with full Node privileges.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for chai-utils-test (6 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging chai-utils-test across your stack and pipelines.
If you installed it — respond
chai-utils-test 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-utils-test was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks chai-utils-test before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks chai-utils-test-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.