Remove obfuscated RCE payload from postcss.config.mjs and restore .gitignore - #1
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Remove obfuscated RCE payload from postcss.config.mjs and restore .gitignore#1kevpay wants to merge 1 commit into
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postcss.config.mjs carried an obfuscated JavaScript payload appended after the legitimate
config, hidden behind a long run of spaces on the closing line so it sits
off-screen in an editor. Restored to its pre-tampering content.
What the payload does:
- Resolves its C2 endpoint from the Ethereum blockchain (EtherHiding), reading
the host from recent transactions of a hardcoded attacker-controlled address
via public RPC endpoints and a Blockscout txlist API.
- Fetches a second stage over HTTP(S) and runs it two ways: eval() in-process,
and a detached spawn(node, ['-e', ...]) with stdio 'ignore' and windowsHide,
unref'd so it outlives the parent.
postcss.config.mjs executes_on_every_build_and_dev_server_start, so this ran on developer
machines and in CI.
.gitignore was rewritten by the same commit: line endings converted, the .env
entry deleted, and a config.bat entry added. Removing .env from .gitignore
stages local secrets to become committable. Restored to its pre-tampering
revision.
The payload first arrived in a141bdd_("fix_missing_promise",_2025-10-11),_and_was_replaced_with_a_newer_variant_by_191cd0d_("remove_polin_rider",_2026-05-27).
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Summary
postcss.config.mjscarried an obfuscated JavaScript payload appended after the config, hidden behind a long run of spaces on the closing line so it sits off-screen in an editor. The attacker also prepended acreateRequireshim to the top of the file so the payload could reachnode:child_processfrom an ESM config..gitignorewas rewritten by the same activity to delete the.enventry and addconfig.bat.What the payload does
txlistAPI.eval()in-process, and a detachedspawn(node, ['-e', ...])withstdio: 'ignore'andwindowsHide,unref()'d so it outlives the parent.postcss.config.mjsexecutes on every build and dev server start.Provenance
The payload arrived in
a141bdd("fix missing promise", 2025-10-11) — one day after the repo was created — and was replaced with a newer, blockchain-C2 variant by191cd0d("remove polin rider", 2026-05-27), a commit intended as a cleanup that shipped a fresh payload instead. That points at the committing machine rather than CI.Worth noting this repo is an example intended for others to copy, so anyone who cloned it may have executed the payload on their own machine.
Scope note
This PR cleans the current tip only; the payload remains reachable in history. Ten other org repositories carry the same campaign, and any credentials reachable from an affected machine or CI run should be treated as compromised.
Generated by Claude Code