MAL-2026-12656

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/cobrowsing-logger/MAL-2026-12656.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-12656
Published
2026-08-05T13:58:28Z
Modified
2026-08-05T14:36:10.717434587Z
Summary
Malicious code in cobrowsing-logger (npm)
Details

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

Source: amazon-inspector (8d5fcbe415de738c1434d79c5b40d1afb7ea916b5ed4b7103b29e244e27169ea)

index.js unconditionally requires _adapter.js on load. _adapter.js reconstructs destination hostnames from string-split fragments (assembling oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev, and sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru at runtime), platform-branches on the host OS, downloads an opaque executable over HTTPS with a DNS-TXT base64 fallback under the *.dl.wel1.ru zone, writes it to /tmp or %TEMP% under a decoy filename (.cache_<hex> on POSIX, dotnet_diag_<hex>.exe on Windows), chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe. An opt-out branch is gated on generic-telemetry environment variables to mimic benign analytics behavior. The dropped binary is not shipped in the tarball and is not verified by hash or signature; whatever the operator of the Workers hosts / DNS-TXT channel serves at fetch time runs detached on the installer's machine on every require('cobrowsing-logger').

Database specific 
{
    "malicious-packages-origins": [
        {
            "source": "amazon-inspector",
            "import_time": "2026-08-05T14:20:03.525641214Z",
            "sha256": "8d5fcbe415de738c1434d79c5b40d1afb7ea916b5ed4b7103b29e244e27169ea",
            "id": "IN-MAL-2026-015114",
            "modified_time": "2026-08-05T13:58:28Z",
            "versions": [
                "35.7.7"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / cobrowsing-logger

Package

Name
cobrowsing-logger
View open source insights on deps.dev
Purl
pkg:npm/cobrowsing-logger

Affected ranges

Affected versions

35.*
35.7.7

Database specific

indicators 
{
    "package_integrity": [
        {
            "filename": "cobrowsing-logger-35.7.7.tgz",
            "hashes": {
                "sha512_sri": "sha512-n+7xuergfAUuaASsiCn1s0xzQNZQECCLiXreGLU1XDZxMeFQ0jbAf6kgjIE3UxSOjlLFHReBVdt4jRYeoX9BYQ==",
                "sha1": "d1d2e8de791cc43395f40e4965d6c629faddbbbd"
            }
        }
    ],
    "evidence_files": [
        {
            "tlsh": "53a1a99a16aa70084bb0d7f4c6174416f65bf6633780c294f75ca9885fb2524c3b2efc",
            "sha256": "4a407d179200dc453b3056bdc0530065af1e2f9f41e18e65f175ae827a54c37c",
            "path": "_adapter.js"
        }
    ]
}
cwes 
[
    {
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code",
        "cweId": "CWE-506"
    }
]
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/cobrowsing-logger/MAL-2026-12656.json"