# MAL-2026-11823: Malicious code in @servicetitan/anvil2-codemods (npm)


- **Type:** Malicious package
- **Package:** `@servicetitan/anvil2-codemods` (npm)
- **Published:** 4 Aug 2026
- **Also known as:** GHSA-cr8r-xmh7-jrh8

## What is MAL-2026-11823?

MAL-2026-11823 is a malicious package in @servicetitan/anvil2-codemods, published on 4 Aug 2026. 

### Official description

npm/@servicetitan/anvil2-codemods 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 Math_Symbol.js / math_init.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.

The package declares a preinstall lifecycle hook (`node setup.mjs`) that downloads the Bun runtime (bun-v1.3.13) from github.com/oven-sh/bun releases into a temporary directory, marks it executable, and invokes it against a sibling file `math_init.js` shipped in the tarball. `math_init.js` is a ~727 KB Bun-CJS bundle prefixed with `// @bun @bun-cjs` that uses a large string-array with a rotator function (`WV8StW`) and a per-call decoder (`hc1jfK9`) over an alphabet string to reconstruct identifiers and strings at runtime — string-array obfuscation. `setup.mjs` itself uses `_0x`-style obfuscated identifiers. The package's advertised purpose is jscodeshift codemods, which does not require a second language runtime; the declared `bin/anvil2-codemods.js` entry does not reference `math_init.js`, so the obfuscated payload is reachable only through the preinstall path. Installing the package causes a downloaded runtime to execute opaque, obfuscated code on the installer at `npm install` time. This is materially different from the aggressive-but-legitimate pattern of fetching an official runtime to run the package's own transparent code: here the code executed under the fetched runtime is obfuscated and unrelated to the package's stated function.

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.

## What should I do about MAL-2026-11823?

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-2026-11823 is a malicious package: @servicetitan/anvil2-codemods (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-2026-11823/ (Markdown: https://insights.sbomify.com/MAL-2026-11823/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-11823

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-11823/
Summaries are generated and may contain mistakes; the official description above is the record.