Which versions of blue-string-formatter-utils are malicious?

The following npm versions of blue-string-formatter-utils are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate blue-string-formatter-utils if I installed it?

Remove blue-string-formatter-utils from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

I already installed blue-string-formatter-utils — how do I know if it already compromised me?

If blue-string-formatter-utils 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.

Is blue-string-formatter-utils part of a known attack campaign?

Yes — blue-string-formatter-utils is associated with the IN-MAL-2026-020171 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find blue-string-formatter-utils across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for blue-string-formatter-utils (version 1.0.0).

Malicious package

blue-string-formatter-utilsnpm

Advisory published Sep 17, 2026Updated Sep 18, 2026

blue-string-formatter-utils is a confirmed malicious npm package (MAL-2026-16273) that executes malicious code on install (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in blue-string-formatter-utils (npm)

MAL-2026-16273

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall blue-string-formatter-utils

What this malware does

The package advertises itself as 'Utility helpers for string formatting' but its shipped main file performs a single behavior: an XMLHttpRequest GET to the protocol-relative URL //xss.report/c/k3rne111 whose response body is passed directly to eval(). Any require()/import of this package causes arbitrary attacker-controlled JavaScript from xss.report to execute in the consumer's Node process, with no pinning, no integrity check, and no relationship to the advertised functionality. The mismatch between the package's stated purpose (string utilities) and its actual contents (a remote-code loader) is a cover-story pattern.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

aa3c9f5edcc636fc8d38e40a6bb225aed8f6b638be31f2abf8b6e747212c9565

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for blue-string-formatter-utils (version 1.0.0).
If you installed it — respond
Remove blue-string-formatter-utils from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If blue-string-formatter-utils 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. blue-string-formatter-utils 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-2026-020171

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks blue-string-formatter-utils-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.

Malware detection Runtime egress monitoring

Explore

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