MAL-2026-13042

See a problem?
Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/boxy-esm-shims/MAL-2026-13042.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-13042
Published
2026-08-05T14:31:59Z
Modified
2026-08-05T15:51:55.543582429Z
Summary
Malicious code in boxy-esm-shims (npm)
Details

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

Source: amazon-inspector (c8f8bbecdfed31ec416782f6de127cb1003692978560504d748acd121b30fa3b)

On require() of the package, index.js loads vendor.js which fetches an opaque binary from string-obfuscated Cloudflare Workers hosts (oob-worker.cf103-07.0.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-TXT base64 fallback under *.wel1.ru (sdk.dl.wel1.ru). The downloaded bytes are written to /var/tmp or %TEMP% under a disguised name (.cache<hex> on Unix, dotnetdiag<hex>.exe on Windows), chmodded 0755, and spawned detached via /bin/sh -c or cmd.exe with unref(). Destination hostnames and the childprocess require are assembled from split string fragments via Array.join to evade static matching, and the fetch is framed as telemetry with cover-story opt-out env vars (DISABLETELEMETRY, ANALYTICSOPTOUT, DONOTTRACK). A TTL stamp file suppresses repeat execution.

Database specific 
{
    "malicious-packages-origins": [
        {
            "source": "amazon-inspector",
            "modified_time": "2026-08-05T14:31:59Z",
            "sha256": "c8f8bbecdfed31ec416782f6de127cb1003692978560504d748acd121b30fa3b",
            "import_time": "2026-08-05T15:19:45.625781492Z",
            "id": "IN-MAL-2026-015338",
            "versions": [
                "35.5.5"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / boxy-esm-shims

Package

Name
boxy-esm-shims
View open source insights on deps.dev
Purl
pkg:npm/boxy-esm-shims

Affected ranges

Affected versions

35.*
35.5.5

Database specific

indicators 
{
    "package_integrity": [
        {
            "filename": "boxy-esm-shims-35.5.5.tgz",
            "hashes": {
                "sha512_sri": "sha512-zSQ3QKqloavh42Ql3VQMcCY1sK/pFJdztBMUuRPDpLpLhZIMKaF5Z4vGYhvHLiBtAjwlapz8g3eBwXF2ctR2eA==",
                "sha1": "5bc5ac11150d06a72552fc97dffdd10440386d9a"
            }
        }
    ],
    "evidence_files": [
        {
            "tlsh": "03b1b85a166970188bb0ebe4c7175416f666f6633380c698fb9c55d41fb2124c3b2efc",
            "sha256": "ca6331e5438ae6eb0538e339e031bed52c19145d42828f5dce898757e71b835b",
            "path": "_vendor.js"
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/boxy-esm-shims/MAL-2026-13042.json"
cwes 
[
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    }
]