MAL-2026-12665

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/contract-contract-builder/MAL-2026-12665.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-12665
Published
2026-08-05T13:58:51Z
Modified
2026-08-05T14:36:14Z
Summary
Malicious code in contract-contract-builder (npm)
Details

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

Source: amazon-inspector (3758ab87194c554acffc80e8cd2caf8fa8890e92854115edab08615877f22b5f)

On require() of the package, platform.js downloads a platform-specific binary from Cloudflare Workers hosts whose names are assembled at runtime from split string fragments (oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev). The fetched bytes are written to /tmp or %TEMP% under disguising names (.cache on POSIX, dotnet_diag_.exe on Windows), chmodded 0755, and spawned detached via cp.spawn("/bin/sh", ["-c", fp+" &"], {detached:true}) or the Windows equivalent. A DNS-TXT fallback channel under *.dl.wel1.ru reassembles a base64 payload from numbered TXT records (c., 0., 1.,...) when HTTPS delivery fails. The package advertises itself as a UI toolkit; the fetched binary is unrelated to that purpose, unpinned, unverified, and executed on import.

Database specific 
{
    "malicious-packages-origins":  [
        {
            "id":  "IN-MAL-2026-015117",
            "import_time":  "2026-08-05T14:20:03.835543125Z",
            "modified_time":  "2026-08-05T13:58:51Z",
            "sha256":  "3758ab87194c554acffc80e8cd2caf8fa8890e92854115edab08615877f22b5f",
            "source":  "amazon-inspector",
            "versions":  [
                "35.5.2"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / contract-contract-builder

Package

Name
contract-contract-builder
View open source insights on deps.dev
Purl
pkg:npm/contract-contract-builder

Affected ranges

Affected versions

35.*
35.5.2

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":  "_platform.js",
            "sha256":  "847545fac36267fd125c40480b2bbfc75cb83ac391fd85515ede82446c865fee",
            "tlsh":  "06a1856a11a570188bb0dbe1c2176416f66bf6632281c5d4f69c69d80ff622483b3efc"
        }
    ],
    "package_integrity":  [
        {
            "filename":  "contract-contract-builder-35.5.2.tgz",
            "hashes":  {
                "sha1":  "85b17bb10fa7f3776ca6a5e794645f9ff4a5dd6c",
                "sha512_sri":  "sha512-s+TL/tIAm+JiI4m5169sgfVWQBlrQWjJhOYyiEFo4WQNmrEGAENsQWEJAbD/d23P3gjO4R33D3E3ju2sXIXlow=="
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/contract-contract-builder/MAL-2026-12665.json"