The @dexwilt/node-fetch package impersonates the legitimate node-fetch project: its package metadata copies the upstream repository, author, and homepage while publishing under an unrelated scope. Its CommonJS entry point lib/index.js contains the expected node-fetch implementation followed by approximately 94 KB of additional RC4/Base64-obfuscated code. The ESM builds do not contain this appended payload.
Agent-assisted deobfuscation of the appended payload recovered a cross-platform download and execution chain. It retrieves a remote binary from an encrypted endpoint, records and verifies the downloaded file's SHA-256 value, and starts the binary with detached, hidden-window, and ignored-stdio options before unreferencing the child process. The original obfuscated source independently exposes the detached, windowsHide, stdio, environment, working-directory, size, SHA-256, and download timestamp fields used by this chain. Loading the package's declared main entry point therefore executes a concealed remote payload loader embedded after otherwise legitimate node-fetch code.
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@dexwilt/node-fetch impersonates the popular node-fetch package under a personal scope. Its main entrypoint (lib/index.js, lib/index.mjs, lib/index.es.js) ships the legitimate node-fetch v2 source with two appended, heavily obfuscated self-executing IIFEs that contain RC4+base64 string-array decoders reconstructing calls to https.request, fs.writeFileSync, fs.chmodSync, and child_process.spawn. Execution is gated on process.env.npm_config_user_agent — set by npm/yarn/pnpm during install but absent in plain node/REPL runs — so the payload only fires inside real installs while staying dormant during casual inspection. When triggered, the code re-spawns the current Node process detached with stdio ignored, downloads a remote binary over HTTP(S), writes it to a temp directory, chmods it 0o755, and execs it detached with windowsHide and unref(). Two independent dropper IIFEs are present in the same file, each with its own decoder and download→write→spawn pipeline, increasing reliability. Any developer or build pipeline that requires or installs this package automatically runs attacker-controlled code with persistence beyond the npm process.
{
"malicious-packages-origins": [
{
"id": "IN-MAL-2026-010977",
"import_time": "2026-08-04T21:33:12.020828822Z",
"modified_time": "2026-08-04T21:11:48Z",
"sha256": "416d6cd82361af6b046d895f23d5e82a82db236a104726914595c21288e33ed0",
"source": "amazon-inspector",
"versions": [
"2.7.3"
]
}
]
}[
{
"cweId": "CWE-506",
"description": "The product contains code that appears to be malicious in nature.",
"name": "Embedded Malicious Code"
},
{
"cweId": "CWE-506",
"description": "The product contains code that appears to be malicious in nature.",
"name": "Embedded Malicious Code"
}
]
{
"evidence_files": [
{
"path": "lib/index.js",
"sha256": "424b4a64884219d678397ef07dc45e0f972819c90ce0faab05c87902d7279415"
}
],
"package_integrity": [
{
"filename": "node-fetch-2.7.3.tgz",
"hashes": {
"sha1": "3ae6eb62ade291206fb2a181c06c1c6217e9aa22",
"sha256": "d44b3b85a41ed3a20b714acb0a9b21376ad2759171f6d8cee7cd5a4433994ae3",
"sha512_sri": "sha512-HXZfNI0k1FQypo1PVpg+fDxpUxNFTq0Dz3T+5Gq/7WrU+vfMq6pAooIOd9dCKwppkCFWBBiM4+V8n15N5Agopg=="
}
}
]
}
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/@dexwilt/node-fetch/MAL-2026-11203.json"