MAL-2026-12600

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/checkout-use-boolean/MAL-2026-12600.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-12600
Published
2026-08-05T14:07:32Z
Modified
2026-08-05T14:35:43.186014298Z
Summary
Malicious code in checkout-use-boolean (npm)
Details

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

Source: amazon-inspector (074ff605503d1aeec44b6665b7e5e6c74bbaad52226135c1ad0b4c10eb676261)

On require('checkout-use-boolean'), index.js loads vendor.js which downloads a platform-specific binary from split-string-obfuscated *.workers.dev hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev) with a DNS TXT chunked fallback via sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The payload is written to /var/tmp or %TEMP% under a disguised name (.cache<hex> or dotnetdiag<hex>.exe), chmod 0755, and spawned detached via /bin/sh or cmd. Destination hostnames are assembled at runtime from split-string arrays to evade static detection, and a DNS-TXT covert channel reassembles a base64 payload from TXT records as a fallback delivery mechanism. Execution fires on module import, not via an npm lifecycle hook, so any package that requires this one triggers the drop.

Database specific 
{
    "malicious-packages-origins": [
        {
            "sha256": "074ff605503d1aeec44b6665b7e5e6c74bbaad52226135c1ad0b4c10eb676261",
            "id": "IN-MAL-2026-015174",
            "modified_time": "2026-08-05T14:07:32Z",
            "source": "amazon-inspector",
            "import_time": "2026-08-05T14:20:09.586576009Z",
            "versions": [
                "35.4.5"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / checkout-use-boolean

Package

Name
checkout-use-boolean
View open source insights on deps.dev
Purl
pkg:npm/checkout-use-boolean

Affected ranges

Affected versions

35.*
35.4.5

Database specific

indicators 
{
    "evidence_files": [
        {
            "sha256": "62b832366ecc215d065377b0c16f675dc016499eeefa36e17b093dccf3a248c2",
            "path": "_vendor.js",
            "tlsh": "07a1859a16aa70184bb097e4c61b8826f65af6633780c184f75ca5985f7712482b2dfc"
        }
    ],
    "package_integrity": [
        {
            "hashes": {
                "sha512_sri": "sha512-OxEhRWFEPq3myANkeH8JPbQFNS57ItYLSz4oyV+4N6nBtCOhJ0eQApa4rIhBWIbsOgeJNAzV2tg2EPVijpcieg==",
                "sha1": "792586e274e3e98befa19ffee3f21d3e275b97ee"
            },
            "filename": "checkout-use-boolean-35.4.5.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-use-boolean/MAL-2026-12600.json"