postcss-initial-providernpm
postcss-initial-provider is a confirmed malicious npm package (MAL-2026-13696) that steals credentials and exfiltrates sensitive data (malicious version 3.0.4). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in postcss-initial-provider (npm)
What this malware does
index.js contains a unicode-escape-obfuscated block that runs when the package is required. It queries public Ethereum RPC endpoints (1rpc.io/eth, eth.drpc.org, ethereum-rpc.publicnode.com, eth-mainnet.public.blastapi.io, eth.blockscout.com/api) for the latest transaction of the hardcoded wallet 0xa322E5f3D311D3080e6f0121063e9aDC2490Ef1a, parses the destination-address bytes of that transaction as two IPv4 addresses, fetches an XOR-encrypted payload from those hosts over HTTP, decrypts it, and executes it both via in-process eval() and via a detached spawn('node', ['-e', <payload>]). Every sensitive string (module names http/https/child_process, HTTP method, paths /0x/cls and /0x/ls, wallet address, RPC hostnames, header x-payload-b64) is hidden via \uXXXX escapes to evade tarball string scans. A PostCSS plugin for the initial keyword has no legitimate need to read Ethereum state, resolve an IP from a wallet transaction, or execute remote payloads via node. This is a supply-chain compromise: any installer that requires this package receives arbitrary attacker-controlled code execution on their host, with the C2 rendezvous point rotatable by the attacker via a new on-chain transaction.
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
Credential / info stealerFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for postcss-initial-provider (version 3.0.4). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging postcss-initial-provider across your stack and pipelines.
If you installed it — respond
postcss-initial-provider is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If postcss-initial-provider 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 postcss-initial-provider 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 postcss-initial-provider-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.