registry  /  @tabrex/bs58  /  6.0.3

@tabrex/bs58@6.0.3

Base 58 encoding / decoding

OSV Malicious Advisory

scanned 2h ago · by OpenSSF/OSV

OpenSSF/OSV advisory MAL-2026-10523 confirms this npm version as malicious. @tabrex/bs58 ships the verbatim README, API surface, and repository URL of the legitimate cryptocoinjs/bs58 package (package.json declares repository https://github.com/cryptocoinjs/bs58 and the README contains 'npm i --save bs58' instructions for that real package), but the bundled entrypoints src/cjs/index.cjs and src/esm/index.js have a heavily obfuscated payload appended after the base58 implementation...

Advisory
MAL-2026-10523
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in @tabrex/bs58 (npm)
Details
@tabrex/bs58 ships the verbatim README, API surface, and repository URL of the legitimate cryptocoinjs/bs58 package (package.json declares repository https://github.com/cryptocoinjs/bs58 and the README contains 'npm i --save bs58' instructions for that real package), but the bundled entrypoints src/cjs/index.cjs and src/esm/index.js have a heavily obfuscated payload appended after the base58 implementation. The payload uses an Obfuscator.io-style rotated string array decoded via RC4 (function a5() with a base64 alphabet decoder feeding a4()), control-flow flattening with a `while(!![])` switch dispatcher, and a self-defending anti-debug check. At require()/import time the payload re-spawns the host Node process detached with a sentinel env var (`spawn(process.argv[0],..., {detached:true, stdio:'ignore', windowsHide:true, env:w, cwd:y})`), downloads an encrypted binary over HTTPS to a destination hidden inside the obfuscated string array, verifies its SHA256 against a sidecar.metadata.json, AES-256-GCM-decrypts it with a key derived from XORing four base64 fragments, then chmods and executes the decrypted binary. Any project that installs and loads @tabrex/bs58 (directly or transitively) executes attacker-controlled code on the developer/build machine on first require. Combination of typosquat lure of a top-tier crypto package, README/repo impersonation, heavy obfuscation, and remote-fetch-decrypt-exec at module-load time is unambiguous supply-chain attack.
Decision reason
OpenSSF Malicious Packages via OSV confirms @tabrex/bs58@6.0.3 as malicious (MAL-2026-10523): Malicious code in @tabrex/bs58 (npm)

Source & flagged code

0 flagged
No flagged code excerpts are attached to this scan.

Findings

1 High
HighOsv Malicious Advisory