MAL-2026-12586

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/checkout-post-installment-client-agreement-accept-am/MAL-2026-12586.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-12586
Published
2026-08-05T14:08:52Z
Modified
2026-08-05T14:35:36.481412655Z
Summary
Malicious code in checkout-post-installment-client-agreement-accept-am (npm)
Details

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

Source: amazon-inspector (3562600b17ec6918b0ebfda948a4579addb4bf1d55a39c696bf6b10fcc15020f)

On require(), index.js loads support.js which assembles Cloudflare Workers hostnames (oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf103-070.workers.dev) via array-join concealment and fetches a platform-specific binary over HTTPS, with a DNS-TXT base64-chunk fallback channel served from sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru and net.dl.wel1.ru. The retrieved bytes are written to a temp path with a disguised name (.cache<rnd> on Unix, dotnetdiag<rnd>.exe on Windows), chmod 0755'd, and detached-spawned via /bin/sh -c or cmd /c start, so the payload runs at import time with the installer's privileges. A second dropper implementation with the same fetch/write/chmod 755/spawn primitives is bundled in lib/telemetry.js under an 'Analytics SDK' cover story, using concatenated API names (chmod+Sync, child_+process) and base64 buffer decoding. Package name and 'telemetry/analytics' framing are cover-story labels; the actual behavior is remote code delivery and execution on the installer's host from author-controlled infrastructure.

Database specific 
{
    "malicious-packages-origins": [
        {
            "sha256": "3562600b17ec6918b0ebfda948a4579addb4bf1d55a39c696bf6b10fcc15020f",
            "id": "IN-MAL-2026-015184",
            "modified_time": "2026-08-05T14:08:52Z",
            "source": "amazon-inspector",
            "import_time": "2026-08-05T14:20:10.59964593Z",
            "versions": [
                "35.2.3"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / checkout-post-installment-client-agreement-accept-am

Package

Name
checkout-post-installment-client-agreement-accept-am
View open source insights on deps.dev
Purl
pkg:npm/checkout-post-installment-client-agreement-accept-am

Affected ranges

Affected versions

35.*
35.2.3

Database specific

indicators 
{
    "evidence_files": [
        {
            "sha256": "c38f749b835577d11fb9bb9fe9a1c37a99cfa8a027476434c85019db6dbb71c9",
            "path": "_support.js",
            "tlsh": "92a1875a16a670198b70ebe4c7175816f65af6633380c2d4f79c59941fb312483b2efc"
        },
        {
            "sha256": "ec1c30eb1c6eb66319649d5dae8df8a05ced88a0c0559a904f68ec79da28f6b2",
            "path": "lib/telemetry.js",
            "tlsh": "27835055566a602186b2b368df234107ff3685272643429dbafc82dc1fbd72092a5ffc"
        }
    ],
    "package_integrity": [
        {
            "hashes": {
                "sha512_sri": "sha512-pxQeEY3W+F3PL8cT4oWjvKyflyBxBAanxeSaDg9j9L9sm43ll0DLTyE2QAB3n9HzN9HLujqZ6rmTf0KN8G1/Lg==",
                "sha1": "d5aae9b1e9e09f6ef65051351f439d2abbc47a21"
            },
            "filename": "checkout-post-installment-client-agreement-accept-am-35.2.3.tgz"
        }
    ]
}
cwes 
[
    {
        "name": "Embedded Malicious Code",
        "description": "The product contains code that appears to be malicious in nature.",
        "cweId": "CWE-506"
    }
]
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/checkout-post-installment-client-agreement-accept-am/MAL-2026-12586.json"