# MAL-2026-4255: Malicious code in cdk-sagemaker-notebook-workflow (npm)


- **Type:** Malicious package
- **Package:** `cdk-sagemaker-notebook-workflow` (npm)
- **Published:** 22 May 2026

## What is MAL-2026-4255?

MAL-2026-4255 is a malicious package in cdk-sagemaker-notebook-workflow, published on 22 May 2026. 

### Official description

The package declares a `preinstall` hook (`node index.js`) in package.json that fires automatically on `npm install`. The script collects `os.hostname()`, `os.userInfo().username`, `os.platform()`, current working directory, home directory, the contents of `/etc/passwd` (`fs.readFileSync('/etc/passwd', 'utf8')`), and the first 30 entries of `process.env` (`Object.entries(process.env).slice(0, 30)`), then POSTs the JSON payload to `https://3nrgzlqwix6erldow0s0kttsojuai36s.oastify.com/greengrass/<execId>` — a Burp Collaborator-style OAST host. Bulk env-var enumeration on CI runners typically captures `AWS_SECRET_ACCESS_KEY`, `GITHUB_TOKEN`, `NPM_TOKEN`, and similar credentials. The package name impersonates the AWS CDK construct namespace (`cdk-sagemaker-notebook-workflow`) and the README contains the string `Takeover By l0bo`, confirming attacker intent. This is an unambiguous install-time credential and host-data exfiltrator with a typosquat lure on the AWS CDK ecosystem.

The OpenSSF Package Analysis project identified 'cdk-sagemaker-notebook-workflow' @ 2.0.5 (npm) as malicious.

It is considered malicious because:

- The package communicates with a domain associated with malicious activity.

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

## What should I do about MAL-2026-4255?

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-2026-4255 is a malicious package: cdk-sagemaker-notebook-workflow (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-2026-4255/ (Markdown: https://insights.sbomify.com/MAL-2026-4255/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4255

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-4255/
Summaries are generated and may contain mistakes; the official description above is the record.