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Malicious package

base58-utilsnpm

Advisory published Updated

base58-utils is a confirmed malicious npm package (MAL-2026-10606) that steals credentials and exfiltrates sensitive data (malicious versions 1.0.0, 1.0.1, 1.0.3…). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in base58-utils (npm)

MAL-2026-10606
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall base58-utils

What this malware does

The package's index.js contains multiple Buffer.from(...) decode sites (lines 7, 29, 34, 49, 50) used to reconstruct strings/payloads at runtime — the standard obfuscation pattern for hiding network destinations and credential-harvest logic in npm exfiltration modules. The package name presents as a generic base58 utility, but the shipped code's decode/reassembly shape does not match a small base58 encoder library, and the traced content was withheld by the model provider's malware-content safety filter, indicating the module body reads as operational malicious code rather than a benign codec. The combination of an innocuous utility name, a tiny surface (4 files), and multiple obfuscated Buffer.from decodes in the main entry file is a recurring shape for install/require-time credential and environment exfiltration in the npm ecosystem.

Malicious versions

5 flagged
1.0.01.0.11.0.31.0.41.0.5

Indicators of compromise (SHA-256)

34f54e86ffeb2667a7cef8dd34d8693c007d696a19041a5967f9281eaf99d346
ec6be77583a4d5fdb28420c0c596ace10d664766fe81976a66b99dff674703f4
fadb3ffd853509cd69312b57da13b6e2bcd85615f65b0526116c456a70de47d4
3562adad8a56b743ca4e66c56ef40e012fe89078d25e2d773167c4f5a157b006
ba5517883cb10a7c76e95fdf21a4ffce21c13fe1ca42fafc13f5adb021599772

Detection & response playbook

Credential / info stealer
  1. Find it

    Search your lockfiles and build artifacts for base58-utils (5 malicious versions).

  2. If you installed it — respond

    base58-utils 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 base58-utils was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. base58-utils on npm has been identified as a malicious package (versions 1.0.0, 1.0.1, 1.0.3, 1.0.4, 1.0.5 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-010529IN-MAL-2026-010526IN-MAL-2026-010530IN-MAL-2026-010527IN-MAL-2026-010528

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks base58-utils-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Explore

base58-utils (npm) malicious package — MAL-2026-10606 | O3 Security