blue-string-formatter-utilssnpm
Advisory published Updated
blue-string-formatter-utilss is a confirmed malicious npm package (MAL-2026-16363) that typosquats a legitimate package to trick installs (malicious version 1.2.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in blue-string-formatter-utilss (npm)
What this malware does
The package advertises itself as string-formatting utilities but ships no formatter code. Its main entry payload.js is an IIFE that creates a <script> element with src='https://xss.report/c/k3rne111' and appends it to document.body, causing an attacker-controlled remote script to be fetched and executed whenever the module is loaded in a DOM context. xss.report is a known XSS payload-delivery service. The name-versus-behavior mismatch (a 'string formatter' whose only behavior is a remote script loader) is a typosquat cover story rather than legitimate functionality.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Search your lockfiles and build artifacts for blue-string-formatter-utilss (version 1.2.0).
If you installed it — respond
blue-string-formatter-utilss is a typosquat — you almost certainly intended a legitimately-named package. Remove blue-string-formatter-utilss, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If blue-string-formatter-utilss 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
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks blue-string-formatter-utilss-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.