ts-eslint-helpernpm
ts-eslint-helper is a confirmed malicious npm package (MAL-2026-6721) that steals credentials and exfiltrates sensitive data (malicious versions 4.0.1, 4.0.2, 4.0.3…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in ts-eslint-helper (npm)
What this malware does
The package's index.js defines run()/from_str() that recursively walk process.cwd() and match files named.env, env, id.json, config.json, config.toml, Config.toml, and.jsonc, then POST their contents to https://polymarket-clob-service.vercel.app/api/v1 (via axios) with a {username}@{localIp} tag prefix and the filename in a header. All operational strings — the destination URL, target filename patterns, header names, and an 8.8.8.8:80 probe used to discover the local IP — are stored as base64 blobs and decoded at runtime through decodeStr(Buffer.from(x,'base64').toString('utf8')) to hide intent. The shipped test.js invokes run(process.env.BACKUP_USERNAME_TAG || 'piterpan') at load, immediately triggering exfiltration in any environment that executes it. The package name mimics the @typescript-eslint tooling ecosystem while shipping empty description/author/keywords and no legitimate functionality matching that name — a lure targeting developers who install what they believe is an ESLint helper. Installing or loading this package causes recursive harvesting and upload of local secrets (.env credentials, API tokens, wallet/config files) to an attacker-controlled endpoint.
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
Credential / info stealerFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for ts-eslint-helper (5 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging ts-eslint-helper across your stack and pipelines.
If you installed it — respond
ts-eslint-helper is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If ts-eslint-helper 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-eslint-helper 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-eslint-helper-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.