bnpl-blocks-utilsnpm
Advisory published Updated
bnpl-blocks-utils is a confirmed malicious npm package (MAL-2026-13022) that executes malicious code on install (malicious version 35.7.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in bnpl-blocks-utils (npm)
What this malware does
On require(), index.js loads loader.js, which assembles a Cloudflare Workers hostname (oob-worker.cf*.workers.dev) via runtime.join('') string reassembly, fetches a platform-specific binary via https.get, writes it to /tmp or %TEMP% under a disguised name (dotnet_diag<hex>.exe on Windows,.cache_<hex> on Linux/macOS), chmods 0755, and spawns it detached via cp.spawn('/bin/sh', ['-c', fp + ' &']) or spawn('cmd',...). If the HTTPS fetch fails, _loader.js falls back to a DNS-TXT covert channel: it resolves TXT records on subdomains of dl.wel1.ru (host fragments also assembled via.join('')), concatenates the returned chunks, base64-decodes them, writes the resulting bytes as an executable, and spawns it. There is no hash or signature verification of the fetched payload. The package presents itself as a generic 'utility functions' library; the remote-binary-drop behavior does not match that stated purpose. Multiple structural fingerprints stack: runtime-obfuscated attacker-controlled hostnames, unpinned mutable payload URLs, DNS-TXT payload staging (a network-egress evasion channel), disguised filenames in system temp directories, and detached execution triggered at module load.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for bnpl-blocks-utils (version 35.7.1).
If you installed it — respond
Remove bnpl-blocks-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 bnpl-blocks-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
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks bnpl-blocks-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.