chai-plugin-kitnpm
chai-plugin-kit is a confirmed malicious npm package (MAL-2026-5906) that executes malicious code on install (malicious version 5.8.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in chai-plugin-kit (npm)
What this malware does
Package republishes the chai source tree under the confusable name chai-plugin-kit. The package's main entry (index.js) spawns a detached, stdio-silenced node subprocess running lib/chai/utils/addAssertion.js on every require('chai-plugin-kit'). That file is heavily obfuscated with obfuscator.io transforms (rotated 31-entry string array _0x4a30, custom base64 decoder _0x495d, hex-named identifiers, control-flow flattening) hiding an https GET to an attacker-controlled URL whose response body is passed to new Function('require', body) and immediately invoked with the real require — granting attacker-controlled JavaScript full Node API access (filesystem, network, child_process, env). The detached + unref + stdio:'ignore' pattern is deliberate evasion to hide the child process from the consuming developer. A legitimate chai plugin has no reason to fetch and eval remote code.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for chai-plugin-kit (version 5.8.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging chai-plugin-kit across your stack and pipelines.
If you installed it — respond
Remove chai-plugin-kit from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If chai-plugin-kit 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-plugin-kit 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-plugin-kit-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.