netspeedutilnpm
Advisory published Updated
netspeedutil is a confirmed malicious npm package (MAL-2026-10438) that opens a backdoor for remote access (malicious version 1.0.13). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in netspeedutil (npm)
What this malware does
On install, setup.js walks up to the installer's project tree and scans image files for a 'STEG' marker. When found, it AES-256-CBC-decrypts an embedded steganographic payload that points to a file inside the installer's node_modules and uses a regex (cli.command("build [root]"...finally{...}) to patch that third-party CLI's build command, prepending an import of netspeedutil/inject.js and an await inject() call inside the build's finally block. Once tampered, every subsequent project build runs inject.js, which uses javascript-obfuscator (control-flow flattening, dead-code injection, base64 string-array encoding) to embed an obfuscated client into dist/index.html. That client opens a WebRTC TURN connection to a hardcoded attacker host at 13.234.111.178:3478 as a covert C2 / signaling channel and renders attacker-supplied DOM content to end users of any site the developer ships. The package's stated purpose ('Fast string matching and pattern validation utilities') is a cover story unrelated to the actual code. This is a build-pipeline supply-chain compromise: the installer's production artifacts are silently weaponized against their own end users.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for netspeedutil (version 1.0.13).
If you installed it — respond
netspeedutil 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 netspeedutil 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 netspeedutil-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.