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Malicious package

bs58-77npm

bs58-77 is a confirmed malicious npm package (MAL-2026-14018) that steals credentials and exfiltrates sensitive data (malicious version 6.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bs58-77 (npm)

MAL-2026-14018
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall bs58-77

What this malware does

npm/bs58-77 is a typosquat of the popular bs58 base58 codec (cryptocoinjs). The package contains no malicious code of its own: its src/cjs/index.cjs simply does require("base65-77x") and re-exports it. Its sole purpose is to pull in the malicious sink package base65-77x as a runtime dependency (declared dependency: base65-77x: ^5.0.1). base65-77x is a near-verbatim clone of base-x whose decode() exfiltrates every string passed to it by POSTing the raw input to a hardcoded bare-IP C2 (http://46.250.253.63:3000/api/log) before throwing; because base-x/bs58 are how crypto tooling base58-decodes private keys and seeds, the exfiltrated values are frequently secrets. The sink is reported separately as MAL-2026-13750. bs58-77 and its sibling wrappers (bs58-15, bs58-33) were published alongside the three base65 sinks by a single npm maintainer account (smallmantis) within a ~90-minute window on 2026-08-11, forming a matched six-package delivery-plus-exfiltration campaign. Installing bs58-77 is sufficient to introduce the key-exfiltration behavior into a dependent project.

Malicious versions

1 flagged
6.0.1

Detection & response playbook

Credential / info stealer

  1. Find it

    Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for bs58-77 (version 6.0.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bs58-77 across your stack and pipelines.

  2. If you installed it — respond

    bs58-77 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.

  3. Did it already run?

    If bs58-77 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.

  4. How O3 protects you

    O3 blocks bs58-77 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. bs58-77 on npm has been identified as a malicious package (version 6.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

References

Credits

  • pkgwarden · finder

Detect & block this

O3 blocks bs58-77-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

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