MAL-2026-12620

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/claims-get-error-string/MAL-2026-12620.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-12620
Published
2026-08-05T14:04:32Z
Modified
2026-08-05T14:35:52.852360652Z
Summary
Malicious code in claims-get-error-string (npm)
Details

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

Source: amazon-inspector (8107a092447bc749767928c38a816191c2af0ea06cb12d6dbeddb9f09b46c698)

On require(), index.js loads ext.js which downloads a platform-specific binary from a set of hardcoded Cloudflare Workers hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev) assembled by string-splitting to evade static matching. The downloaded bytes are written to /var/tmp or %TEMP% under innocuous names (.cache<rnd> on POSIX, dotnetdiag<rnd>.exe on Windows), chmod 0755 is applied, and the binary is spawned detached via /bin/sh -c '<path> &' or cmd. A DNS-TXT covert channel under wel1.ru (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru) reads a chunk count from c.<domain> and base64-reassembles the payload from sequential subdomain TXT records as a delivery fallback. A second module lib/telemetry.js (81KB) is bundled in the tarball with parallel dropper logic (base64 chunk assembly, chmod 0755, cp.spawn('/bin/sh', ['-c', filePath+' &'])) though not reachable from main in this version. No hash pinning, no signature verification, opaque payload, cover-story naming as analytics/telemetry.

Database specific 
{
    "malicious-packages-origins": [
        {
            "sha256": "8107a092447bc749767928c38a816191c2af0ea06cb12d6dbeddb9f09b46c698",
            "id": "IN-MAL-2026-015153",
            "modified_time": "2026-08-05T14:04:32Z",
            "import_time": "2026-08-05T14:20:07.565094538Z",
            "source": "amazon-inspector",
            "versions": [
                "35.5.9"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / claims-get-error-string

Package

Name
claims-get-error-string
View open source insights on deps.dev
Purl
pkg:npm/claims-get-error-string

Affected ranges

Affected versions

35.*
35.5.9

Database specific

indicators 
{
    "evidence_files": [
        {
            "sha256": "a242f14ade81a3463385ec3fc3c47d8f8acb85ac2b75306cf9ba2e379c7bc003",
            "path": "_ext.js",
            "tlsh": "8ea1979a06a670098bb0d7e48a275406f65bf5633780c294fb5ca9985f7712483b2efc"
        },
        {
            "sha256": "1fc89cc0e59bc4da9625b1d5d43b750eb69a5bd1c0d8cd29f670f0bcde1743e7",
            "path": "lib/telemetry.js",
            "tlsh": "89835056566a142186b2b368df234107ff3685272643429dbafc82dc1fbd72092a5ffc"
        }
    ],
    "package_integrity": [
        {
            "hashes": {
                "sha512_sri": "sha512-Q2XH0kDxbqxwQCPWJfKavevBivMJRSktxcmS7CIza7tbf72dEK7nmmLQkN0OMNavhwVLCMaRexBinGJzRSEKQw==",
                "sha1": "452ee8d37f96b40ab9880d7d47acf21e654de34f"
            },
            "filename": "claims-get-error-string-35.5.9.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/claims-get-error-string/MAL-2026-12620.json"