micro-ui-loadernpm
micro-ui-loader is a confirmed malicious npm package (MAL-2026-10564) that opens a backdoor for remote access (malicious versions 2.0.0, 6.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in micro-ui-loader (npm)
What this malware does
On npm install, the package's postinstall script (postinstall.js) reads os.hostname() and sends it as a query parameter in a plain-HTTP GET to a hardcoded bare IP: http://37.60.255.218/skybackground.png?display=<hostname>. The response body is piped to downloaded-image.jpg in the package directory, with redirects followed without validation, staging attacker-controlled bytes on disk. The package's advertised purpose is inconsistent across artifacts — README presents it as 'Simple Text Utils' (capitalize/reverse/wordCount), package.json describes an 'image downloader', and the exported API is only downloadImage. The author is the placeholder string 'Your Name'. The combination of an unsolicited installer-identifying beacon to a bare-IP HTTP endpoint at lifecycle time, attacker-controlled byte staging, and a cover-story mismatch is the install-time reconnaissance pattern.
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 micro-ui-loader (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging micro-ui-loader across your stack and pipelines.
If you installed it — respond
micro-ui-loader 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 micro-ui-loader 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 micro-ui-loader 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 micro-ui-loader-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.