Which versions of evilpostinstall are malicious?

The following npm versions of evilpostinstall are flagged malicious: 49.13.4074225, 4127000.0.1. Treat any of these as compromised.

How do I remediate evilpostinstall if I installed it?

evilpostinstall 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.

I already installed evilpostinstall — how do I know if it already compromised me?

If evilpostinstall 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.

Is evilpostinstall part of a known attack campaign?

Yes — evilpostinstall is associated with the IN-MAL-2026-019308, IN-MAL-2026-019296 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find evilpostinstall across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for evilpostinstall (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging evilpostinstall across your stack and pipelines.

Malicious package

evilpostinstallnpm

evilpostinstall is a confirmed malicious npm package (MAL-2026-15625) that steals credentials and exfiltrates sensitive data (malicious versions 49.13.4074225, 4127000.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in evilpostinstall (npm)

MAL-2026-15625

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall evilpostinstall

What this malware does

The package's postinstall lifecycle hook pipes the output of env through nc to a host reconstructed at install time from the package version string via cut -b 2-4 and cut -b 5-. For version 4127000.0.1 the destination decodes to 127.0.0.1:888; the sibling artifact evilpostinstall-192.168.1.100.tgz uses the same slicing scheme to target 192.168.1.100. On npm install, the full installer environment - including any CI secrets, tokens, and API keys present in environment variables - is transmitted to the reconstructed host over TCP port 888. package.json also declares a self-referencing dependency evilpostinstall: ^4192168.1.100, whose version field encodes a second destination IP under the same scheme, causing npm to resolve and install an additional package instance whose own postinstall repeats the exfiltration against that address. The destination is deliberately hidden from static scanners by being reconstructed from the version field rather than written as an IP literal, and no source files are shipped - the manifest itself is the payload.

Malicious versions

2 flagged

49.13.40742254127000.0.1

Indicators of compromise (SHA-256)

64ca497d518a333a571b7f978e9ce5a5f4a87649d462eb16480a258aa33b15c2

846e500b06f58769a2cb833be8e726ab1db04b327f4c614da6642eb46ae7dfe5

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for evilpostinstall (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging evilpostinstall across your stack and pipelines.
If you installed it — respond
evilpostinstall 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 evilpostinstall 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 evilpostinstall 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

No. evilpostinstall on npm has been identified as a malicious package (versions 49.13.4074225, 4127000.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-019308IN-MAL-2026-019296

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks evilpostinstall-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

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