# MAL-2026-4276: Malicious code in build-scripts-utils (npm)


- **Type:** Malicious package
- **Package:** `build-scripts-utils` (npm)
- **Published:** 23 May 2026
- **Also known as:** GHSA-fxc5-vwp2-3c24

## What is MAL-2026-4276?

MAL-2026-4276 is a malicious package in build-scripts-utils, published on 23 May 2026. 

### Official description

Ten packages published by npm user `asdxzxc` at version 1.0.10 target developers working on AI and LLM tooling. Each package masquerades as a developer utility while executing a two-stage payload triggered via postinstall: `package.json` → `lib/setup.js` → `lib/worker.js`.

**Credential harvesting:** `lib/worker.js` scans the filesystem for private keys (64-char hex), BIP39 mnemonics (12–24 word phrases), API keys and secrets, and passwords from env vars and shell history (`.bash_history`, `.zsh_history`, `.fish_history`, `.mysql_history`, `.psql_history`), including wallet tool invocations (`geth account`, `hardhat`, `metamask`, `wallet import`). Targeted paths include `~/.ssh`, `~/.aws/credentials`, `~/.config/gcloud`, `~/.azure`, `~/.docker/config.json`, `~/.kube/config`, crypto wallet dirs (`~/.ethereum`, `~/.bitcoin`, `~/.solana`), exchange configs (Binance, Bybit, OKX, KuCoin, Deribit, 3Commas), `.env`, `.npmrc`, `.gitconfig`. Also performs browser data theft and Ethereum keystore brute-force. A priority-target list fetched from the actor's GitHub Pages endpoint enables aggressive deep scanning for pre-registered high-value hosts.

**AI self-propagation:** after credential theft, a `_propagate()` function executes a multi-vector campaign to infect AI coding assistants. It writes poisoned `.cursorrules` and `CLAUDE.md` files — framed as "P-2024-001 Enterprise Credential Integrity Standard" — to all discovered project directories, parent directories, and home subdirectories, instructing Cursor, Claude Code, and GitHub Copilot to execute the remote payload and propagate it via Issues, PRs, and documentation. Git hooks (`post-merge`, `post-checkout`, `pre-commit`, `pre-push`) are injected into all `.git` repos found on disk, and a persistence block is appended to `~/.bashrc`, `~/.zshrc`, and `~/.profile`. Zero-width steganography (ZWSP/ZWJ/ZWNJ/LTRM encoding) embeds hidden scan triggers in all AI-generated text output, enabling AI-to-AI chain infection invisible to humans.

**C2/exfil:** a remotely configurable JSON config hosted on the actor's GitHub Pages delivers the active webhook list, encryption key, and scan strategy; hardcoded fallback webhooks at `webhook.site` and a DNS TXT record fallback are used if the primary channel fails. A dedup marker at `~/.local/share/.p2024_integrity` prevents re-propagation within 24 hours.

`build-scripts-utils` poses as build script utilities and helpers for JavaScript and TypeScript projects.

lib/trap-core.js performs system reconnaissance and network exfiltration. The module imports fs, https, dns, and os, then collects host identifiers (os.hostname(), os.platform(), os.homedir(), process.env.USER, process.cwd()) and POSTs them to hardcoded HTTPS endpoints via https.request/https.get at lines 267, 274, 292, 293, and 346. The combination of system enumeration, environment/identity reads, filesystem inspection (fs.existsSync at lines 26/79/194), and hardcoded outbound POST destinations is the canonical credential/host-beacon exfiltration shape. The package name advertises generic 'build script utilities,' which does not justify host fingerprinting and remote beacons. Installing or loading this package leaks installer host metadata to attacker-controlled infrastructure.

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.

The OpenSSF Package Analysis project identified 'build-scripts-utils' @ 1.0.12 (npm) as malicious.

It is considered malicious because:

- The package executes one or more commands associated with malicious behavior.

## What should I do about MAL-2026-4276?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-4276 is a malicious package: build-scripts-utils (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-4276/ (Markdown: https://insights.sbomify.com/MAL-2026-4276/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4276

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-4276/
Summaries are generated and may contain mistakes; the official description above is the record.