thundertigernpm
Advisory published Updated
thundertiger is a confirmed malicious npm package (MAL-2026-13834) that typosquats a legitimate package to trick installs (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in thundertiger (npm)
What this malware does
The package's only shipped content is a single HTML file that mimics a Cloudflare 'Just a moment...' security challenge. The inline script is obfuscated with an obfuscator.io-style shuffled string-array + hex identifier decoder and anti-debug console overrides. After a 1-second delay it assembles a hostname from split literals ('gin.microc' + 'loud.homes' → login.microcloud.homes), forwards the current URL's query string, and calls window.location.replace to redirect the browser to that external host. package.json declares no lifecycle scripts and main points at HTML rather than a loadable JS module, so installing or requiring the package does not directly execute the payload against a developer's machine — the harm is directed at end users who load the hosted HTML, using the npm registry as a CDN for a phishing kit. This is registry/namespace abuse rather than a direct installer-side attack; recommend human review to confirm and to coordinate takedown with the registry.
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Search your lockfiles and build artifacts for thundertiger (version 1.0.0).
If you installed it — respond
thundertiger is a typosquat — you almost certainly intended a legitimately-named package. Remove thundertiger, 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 thundertiger 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 thundertiger-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.