jest-test-plugin-utilsnpm
jest-test-plugin-utils is a confirmed malicious npm package (MAL-2026-5896) that executes malicious code on install (malicious versions 1.0.0, 1.0.1, 1.0.2…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in jest-test-plugin-utils (npm)
What this malware does
The package advertises itself as a Jest plugin (name: 'jest-test-plugin-utils', description: 'mqtt utils') but ships no Jest or MQTT functionality. Its main entry dist/index.js is a heavily obfuscated 200KB browserify bundle (obfuscator.io fingerprint: 1299-entry rotated string array, decoder wrapper, control-flow flattening; built with the declared devDependency 'gulp-javascript-obfuscator'). After deobfuscation, the only meaningful behavior is a function loadFilbetScriptSilently() (exposed as window.fetchFilbetScript) that creates a <script> element with src='https://cdn.jsdelivr.net/gh/gongben2024/network-security@main/src/filbet.js' and appends it to document.head, executing whatever code the author hosts at that mutable @main branch. The destination repository is named 'network-security' under author 'gongben2024' and is unrelated to the package's stated purpose. Because the reference is to the @main branch (not a pinned commit/tag), the author can change the executed payload at any time without republishing this package. Any application that bundles or imports this module will execute attacker-controlled JavaScript in the browser context, with full access to the host page's DOM, cookies, and storage. The combination of name camouflage, heavy obfuscation, and unpinned remote-script execution is a deliberate supply-chain attack pattern.
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 jest-test-plugin-utils (4 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging jest-test-plugin-utils across your stack and pipelines.
If you installed it — respond
Remove jest-test-plugin-utils 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 jest-test-plugin-utils 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 jest-test-plugin-utils 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 jest-test-plugin-utils-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.