MAL-2026-11555

npm/@arv-bedrock/auth-sso is affected by the large-scale, self-propagating npm supply-chain worm of 2026-08-04 (the "Shai-Hulud: Here We Go Again" wave) — the same campaign that began with the compromise of the keyv and cacheable maintainer account. The listed version(s) were trojanized and republished by the worm after it reached an npm publish token belonging to a maintainer in this namespace; the payload enumerates every package a stolen token controls and republishes each with the same hook, so many packages under this scope were poisoned in the same short window. Every poisoned release adds a preinstall hook ("preinstall": "node setup.mjs") that runs on a bare npm install, before any project code. setup.mjs downloads a standalone Bun runtime and runs a byte-identical, heavily obfuscated ~728 KB second-stage credential stealer (shipped as MathSymbol.js / mathinit.js). It harvests GitHub, npm, AWS, GCP, Azure, HashiCorp Vault and Kubernetes credentials plus generic secrets and private keys (TruffleHog-style sweep), reads CI/CD secrets and identifies build runners, then republishes further packages the stolen token can reach. Rather than a fixed command-and-control host, it exfiltrates stolen findings to attacker-created GitHub repositories (descriptions reading "Shai-Hulud: Here We Go Again") and over DNS. Treat any environment that installed an affected version (with install scripts enabled) as compromised: rotate and revoke all reachable credentials (npm and GitHub tokens, cloud keys, Vault/Kubernetes secrets, and CI org/repo secrets). Part of the August 2026 npm worm that poisoned 400+ packages across many organizations.

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Source: amazon-inspector (4695d50ee61e19714421c77692f39a9522c00cd8a5d674c2ae683fd765812bae)

The package declares a preinstall script (node setup.mjs) that runs automatically on npm install. setup.mjs is itself obfuscated (obfuscator.io-style hex identifiers and per-function dictionary indirection) and downloads the Bun runtime from https://github.com/oven-sh/bun/releases/download/bun-v<V>/<arch>.zip, extracts it to a temporary directory, chmods it executable, and invokes it via execFileSync against a bundled 727KB single-line Bun-compiled CJS file math_init.js shipped in the tarball. math_init.js is heavily obfuscated (shuffled string-array decoder function WV8StW rotating the n7gIxM array, hex-named identifiers, // @bun @bun-cjs header) so its contents are executed on the installer's machine under a runtime distinct from Node. The package's advertised purpose is an SSO authentication client, which has no need for a separately downloaded alternate runtime or an obfuscated multi-hundred-kilobyte install-time payload. The loader-plus-opaque-payload structure and the use of Bun specifically to bypass Node-oriented inspection are the defining shape of an alternate-runtime install-time dropper.

Source: ghsa-malware (59cf0bd40312ffba9a99aa92a52802b59f30ff2e352cd870a2bbe7da8827f27e)

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.