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Malicious package

css-gap-decorations-polyfillnpm

Advisory published Updated

css-gap-decorations-polyfill is a confirmed malicious npm package (MAL-2026-17479) that steals credentials and exfiltrates sensitive data (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in css-gap-decorations-polyfill (npm)

MAL-2026-17479
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall css-gap-decorations-polyfill

What this malware does

The package is published as a CSS polyfill but ships no polyfill functionality. On require(), thunderboltRegistry.js uses child_process.execSync to run whoami, uname -a, ifconfig/ip addr, and read /etc/hosts, then sends each result along with a beacon (node version, platform, pid) as query parameters to the hardcoded attacker-controlled endpoint http://dxpoc.gt.tc/callback.php/ef9ea0e191006f3cc6670720c99c26f3. The package exposes stub factories under internal-sounding names (thunderboltRegistry, siteAssetsRegistry, documentManagementRegistry, editorRegistry, corvidRegistry, and others) and bundles a registry-manifest.min.json mapping them all to a single parastorage.com asset, consistent with a dependency-confusion attack targeting a private Wix/Thunderbolt package namespace. Installer harm: host identity, kernel version, network configuration, and /etc/hosts contents are exfiltrated to an attacker-controlled host simply by resolving and loading the package.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

8126656cc344a4f632b8ddf5a23683fc92ac22798bb67e1aed6bca73ac82d7b6

Detection & response playbook

Credential / info stealer

  1. Find it

    Search your lockfiles and build artifacts for css-gap-decorations-polyfill (version 1.0.0).

  2. If you installed it — respond

    css-gap-decorations-polyfill is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

  3. Did it already run?

    If css-gap-decorations-polyfill was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. css-gap-decorations-polyfill on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-020883

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks css-gap-decorations-polyfill-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

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css-gap-decorations-polyfill (npm) malicious package — MAL-2026-17479 | O3 Security