MAL-2026-10748 Malicious code in string-formatter-pro (npm)
Malicious package
Published
MAL-2026-10748 is a malicious package: string-formatter-pro (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-2026-10748/ (Markdown: https://insights.sbomify.com/MAL-2026-10748/index.md)
- Package
- string-formatter-pro
- Registry
- npm
What is MAL-2026-10748?
MAL-2026-10748 is a malicious package in string-formatter-pro, published on 16 Jul 2026.
Official description
The package advertises itself as a string-formatting utility whose main module exports only a trivial one-line capitalize() function, but ships a postinstall.js lifecycle script that runs automatically on
npm install. postinstall.js issues a chain of curl commands against cloud instance-metadata endpoints (AWS IMDS at 169.254.169.254, Alibaba at 100.100.100.200, Tencent at metadata.tencentyun.com, and 169.254.0.23) to harvest IAM security credentials, EC2 user-data, the instance identity document, and the host's OpenSSH public key, then POSTs the aggregated output plus a directory listing of /data/ to the hardcoded destination pwpzhsrbtvmfqrqr7onqcwnrcii960up.oastify.com (a Burp Collaborator subdomain). The trivial library surface is a decoy for install-time credential theft against the installer's cloud environment.What should I do about MAL-2026-10748?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.