Malicious code in dolyame-ui-postcssconfig (npm)
The npm package dolyame-ui-postcssconfig contained malicious code that downloads and executes platform-specific binaries from attacker-controlled Cloudflare Workers and DNS fallback domains upon package import. The package masqueraded as a PostCSS configuration utility for a UI library but performed arbitrary code execution.
- Disclosed
- Last updated
- Blast radius
- Any developer or application that installed dolyame-ui-postcssconfig; arbitrary code execution on affected systems at package require() time.
- Ecosystems
- Attack vectors
- Affected entities
- dolyame-ui-postcssconfignpm package containing malicious code
The npm package dolyame-ui-postcssconfig was found to contain malicious code that executes on require(). The package's index.js and lib/telemetry.js files load code that fetches platform-specific binaries over HTTPS from hardcoded Cloudflare Workers hostnames (oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev), with DNS TXT-record fallback resolution via sdk/ext/pkg/net subdomains of dl.wel1.ru.\n\nThe fetched binaries are written to disguised paths in /var/tmp (POSIX) or the Windows temp directory, made executable (chmod 0755 on POSIX), and spawned as detached processes via /bin/sh -c or cmd.exe. Sensitive API names and destination hostnames are obfuscated at runtime using split string fragments and joined arrays to evade static analysis.\n\nlib/telemetry.js embeds the same malicious download-decode-chmod-spawn pattern within approximately 3000 lines of fake 'Analytics SDK' code, providing a second execution path at import time. The package name and declared purpose (PostCSS configuration) do not match the actual behavior, indicating intentional deception.\n\nThe incident was identified by the OpenSSF malicious-packages project and reported via GitHub Security Advisory GHSA-c25q-g4g2-4ww8.
Indicators of compromise
- Packages
- dolyame-ui-postcssconfig
- Domains
- oob-worker.cf102-baf.workers.dev
- oob-worker.cf101-adf.workers.dev
- oob-worker.cf99-9b3.workers.dev
- oob-worker.cf100-416.workers.dev
- dl.wel1.ru
Remediation
- Immediately uninstall dolyame-ui-postcssconfig from all systems and projects
- Audit npm package.json and lock files for any presence of dolyame-ui-postcssconfig
- Review system logs and process execution history on any machine where the package was installed for signs of unauthorized binary execution
- Regenerate any credentials or API keys that may have been exposed on affected systems
- Monitor network traffic from affected systems for connections to the identified Cloudflare Workers domains and dl.wel1.ru subdomains
- Update npm dependencies and use npm audit to identify any other potentially malicious packages
Sources
- GitHub Advisory GHSA-c25q-g4g2-4ww8 · GitHub Advisory Database
Cite this entry
"Malicious code in dolyame-ui-postcssconfig (npm)." supplychainattack.org, Supply Chain Attack Incident Catalog. Disclosed August 7, 2026; last updated August 7, 2026. https://supplychainattack.org/incident/malicious-code-in-dolyame-ui-postcssconfig-npm-dnj0e6
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