MAL-2026-16101

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/mfaby/MAL-2026-16101.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-16101
Published
2026-09-09T21:10:42Z
Modified
2026-09-09T21:30:03Z
Summary
Malicious code in mfaby (npm)
Details

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

Source: amazon-inspector (c278e0ee3820cf701ef7ad65dfdab43a0765e5d3423286de99d3301fe39a8455)

The package presents itself as a Discord MFA helper, but its cache module contains a _warmSession routine that decodes a base64-encoded string (_CDN_BASE) into the URL https://limbomail.com/api/attachment/l4TIRPOsaUxR._603-vhKDRdgKl3RalN_TVUZYGPsJy2Y, downloads the response body, writes it to a file in os.tmpdir(), and executes it via new Worker(tmp). This chain fires when a consumer calls the documented entry point initMFA(). The fetched payload is opaque, unpinned, and hosted on a domain unrelated to the package's stated Discord functionality. The Discord TLS client additionally sets rejectUnauthorized:false, disabling certificate verification on outbound Discord traffic. The base64 concealment of the drop URL combined with a README cover-story describing it as a 'runtime patch asset' indicates deliberate hiding of the endpoint.

Database specific 
{
    "malicious-packages-origins": [
        {
            "id": "IN-MAL-2026-019900",
            "import_time": "2026-09-09T21:14:32.927492477Z",
            "modified_time": "2026-09-09T21:10:42Z",
            "sha256": "c278e0ee3820cf701ef7ad65dfdab43a0765e5d3423286de99d3301fe39a8455",
            "source": "amazon-inspector",
            "versions": [
                "1.0.0"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / mfaby

Package

Name
mfaby
View open source insights on deps.dev
Purl
pkg:npm/mfaby

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": "lib/http.js",
            "sha256": "662e532b1dbda17dc95ceadb7f8eecdcd020bdc66d638bac17c30ee2464f4330",
            "tlsh": "c8b1439a24f2706946fbd5ec9327e86af3779103714dd9a0f21c82b11f8256c8b665c8"
        },
        {
            "path": "index.js",
            "sha256": "52583b62314f049289a83dfe59ef488e587deea24c45a783a099b953f7631698",
            "tlsh": "a412621121f7203a0363d0ff9bd7d01567345903355ae9b8b78c9684afc361a85b3aee"
        }
    ],
    "package_integrity": [
        {
            "filename": "mfaby-1.0.0.tgz",
            "hashes": {
                "sha1": "f91b1881c1b7059456aa977fc350a83120a1e241",
                "sha512_sri": "sha512-xMFK9+e5hqBwrhHtHX65EFWUMse8lqoERkgtx4ppwSYIePMcWbWix6sMb4p+YM36DUXO9pnNE+Hwsy2zcOtKRw=="
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/mfaby/MAL-2026-16101.json"