ts-vitestnpm
ts-vitest is a confirmed malicious npm package (MAL-2026-10990) that typosquats a legitimate package to trick installs (malicious versions 1.0.7, 1.0.8, 1.0.9…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in ts-vitest (npm)
What this malware does
ts-vitest is a typosquat of vitest/ts-eslint (hollow "kelly-calc"/"clob-math" content, no legitimate functionality) that ships a postinstall two-stage fetch-exec dropper. The package.json declares postinstall: node scripts/install-check.cjs; the hook's resolvePeerBundleUrl() fetches a JSON config from a hardcoded, typosquatting host (https://ts-eslint.vercel.app/config/clob-math.json, also the package.json homepage), reads a second-stage tarball URL out of that config, npm installs the tarball, then require()s and executes it — achieving install-time RCE before any package code is used. The config JSON resolves to a second-stage tarball at https://ts-eslint.vercel.app/releases/psm-peer.tgz, whose main entry point is peer-math.js. The config indirection (an ephemeral *.vercel.app host serving JSON that points at the real payload) keeps the tarball URL out of the package bytes, defeating a naive grep for a hardcoded payload URL.
The lineage alternates malicious and clean releases: 1.1.1 shipped the dropper (previously convicted), 1.1.2 removed the postinstall hook as a clean decoy, and 1.1.3 restores a byte-identical copy of the 1.1.1 dropper. The hook is entirely YARA-invisible (0 matches); detection required reading the hook's logic directly rather than relying on signature scoring. Published by sole npm maintainer naradi (maintainer email [email protected]), who pushed 7 versions in ~6.5 hours.
The package is published as ts-vitest and its README advertises a TypeScript/Jest transformer, but the shipped code is unrelated (a Kelly-stake helper) and the postinstall hook performs install-time remote code execution. On npm install, the postinstall resolves a bundle URL from a JSON config at https://ts-eslint.vercel.app/config/clob-math.json (a lookalike of the legitimate typescript-eslint project), downloads the returned .tgz archive, extracts it, runs npm install inside the extracted directory, then requires peer-math.js and invokes syncSession() in the installer's Node process. There is no version pin, no hash or signature check, and the config host is author-controlled and mutable, so the executed payload can be changed at any time. The name/README cover story combined with the typosquat-style config domain is a deliberate dropper shape.
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
TyposquatFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for ts-vitest (7 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging ts-vitest across your stack and pipelines.
If you installed it — respond
ts-vitest is a typosquat — you almost certainly intended a legitimately-named package. Remove ts-vitest, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If ts-vitest 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 ts-vitest 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
- SafeDep · finder
Detect & block this
O3 blocks ts-vitest-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.