tailwindcss-effectornpm
Advisory published Updated
tailwindcss-effector is a confirmed malicious npm package (MAL-2026-6472) that opens a backdoor for remote access (malicious version 1.7.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in tailwindcss-effector (npm)
What this malware does
src/index.js appends a heavily obfuscated async IIFE after a legitimate-looking TailwindCSS plugin. On import, the IIFE issues HTTPS requests to remote JSON-RPC endpoints (TRON-style transaction queries reading .data[0].raw_data.data, and Ethereum-style eth_call reading result.input.substring(2)), XOR-decrypts the returned hex bytes, and executes them: the primary path calls eval(e) on the decoded payload, and a secondary path spawns a detached child process via child_process.spawn(..., {detached:true, stdio:..., windowsHide:true}) whose output is also eval'd in an error handler. All sensitive strings (URLs, RPC method names, host names, module/method names, argv) are hidden behind a custom string-shuffle decoder _$_d407=(function(b,m){...})("<blob>",3168449), indexed as _$_d407[N]. The package name pattern (effector vs. tailwindcss-animated / tailwindcss-animate) plus malicious code grafted onto a working plugin is consistent with typosquat-with-payload. Anyone who installs and imports this package executes attacker-controlled JavaScript decoded from on-chain RPC responses and gains a persistent detached child process — full RCE on the installer's machine, with the C2 channel hidden inside legitimate-looking blockchain RPC traffic.
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
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for tailwindcss-effector (version 1.7.0).
If you installed it — respond
tailwindcss-effector establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If tailwindcss-effector 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 tailwindcss-effector-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.