ts-poly-utlsnpm
ts-poly-utls is a confirmed malicious npm package (MAL-2026-12811) that executes malicious code on install (malicious version 1.2.4). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in ts-poly-utls (npm)
What this malware does
The package's postinstall script (scripts/install-check.cjs) reads a bundle URL from https://polymarket-clob-service.vercel.app/config/clob-math.json, downloads the referenced.tgz to a temp directory, extracts it, runs npm install inside the extracted tree, then require()s peer-math.js from it and invokes syncSession() at install time. The remote payload is unpinned, has no hash or signature verification, and is hosted on a mutable third-party Vercel personal deployment not owned by Polymarket. Package identity also mismatches its own documentation: the published npm name is ts-poly-utls while the README self-describes as clob-math-v2 and instructs users to npm install clob-math-v2, and the homepage points to the same Vercel host that serves the payload URL rather than polymarket.com. Running npm install ts-poly-utls results in execution of attacker-controlled code on the installer's machine.
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 ts-poly-utls (version 1.2.4). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging ts-poly-utls across your stack and pipelines.
If you installed it — respond
Remove ts-poly-utls 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 ts-poly-utls 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-poly-utls 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 ts-poly-utls-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.