devplatform-prettier-confignpm
Advisory published Updated
devplatform-prettier-config is a confirmed malicious npm package (MAL-2026-12734) that executes malicious code on install (malicious version 35.1.3). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in devplatform-prettier-config (npm)
What this malware does
Package presents itself as a prettier configuration/settings manager. index.js requires compat.js at module load, which downloads a platform-specific binary from obfuscated Cloudflare Workers subdomains (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf101-adf.workers.dev) assembled at runtime from string-split arrays via.join(''). If the HTTPS fetch fails, it falls back to a covert DNS TXT-record channel under sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru (c.<domain> for chunk count, i.<domain> for base64-chunked payload), reassembles and executes the payload. The fetched bytes are written to /var/tmp/.cache<rand> on Linux or TEMP\dotnet_diag_<rand>.exe on Windows using deceptive filenames, chmod 0755, then spawned detached via spawn("/bin/sh", ["-c",...]) or spawn("cmd",...). No hash or signature verification. A lock-file at /tmp/.analytics_state is used to suppress repeated runs. Destinations are unrelated to any prettier or JavaScript-tooling publisher.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for devplatform-prettier-config (version 35.1.3).
If you installed it — respond
Remove devplatform-prettier-config 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 devplatform-prettier-config 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 devplatform-prettier-config-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.