MAL-2026-17305

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/esm-dotenv/MAL-2026-17305.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-17305
Published
2026-09-30T01:28:18Z
Modified
2026-09-30T01:45:10Z
Summary
Malicious code in esm-dotenv (npm)
Details

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

Source: amazon-inspector (55c5c67c48596e011158554f8b5ea57d65a8a8dc3b5f4120d3c9c4d1cf961da2)

The package advertises itself as a zero-dependency dotenv parser but its main entry dist/index.cjs and CLI bin dist/cli.cjs both invoke dispatchAnalytics() at top-level module load. That function reads dist/stest.jpg, walks the JPEG marker structure to extract the APP13 (0xED) segment as UTF-8, treats those bytes as a base64-encoded PowerShell command, writes a relay_*.vbs wrapper into os.tmpdir(), and spawns wscript.exe detached with windowsHide:true to launch powershell.exe -NoProfile -NonInteractive -EncodedCommand <payload>. The powershell.exe and -EncodedCommand strings are assembled from split-array joins (["power","shell",".exe"].join("")) to evade static keyword scanners, and the payload bytes are hidden inside a JPEG segment rather than in JavaScript source. A second shipped loader, dist/decode.js, is heavily obfuscated (string-array + numeric-id lookup) and reconstructs code via RC4-style XOR of a base64 blob (~8 KB decoded) before executing it through new Function('require','module','__filename','__dirname', <decoded>), providing an additional dynamic-code sink. The dropper fires the moment any Windows host imports the package.

Database specific 
{
    "malicious-packages-origins":  [
        {
            "id":  "IN-MAL-2026-020787",
            "import_time":  "2026-09-30T01:36:51.511384896Z",
            "modified_time":  "2026-09-30T01:28:18Z",
            "sha256":  "55c5c67c48596e011158554f8b5ea57d65a8a8dc3b5f4120d3c9c4d1cf961da2",
            "source":  "amazon-inspector",
            "versions":  [
                "1.0.1"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / esm-dotenv

Package

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

Affected ranges

Affected versions

1.*
1.0.1

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":  "dist/index.cjs",
            "sha256":  "97fa0d7666e80c68a3cd4f3326dc31bd9203619d6bbae7449efe62de15c4e815",
            "tlsh":  "4262f784b3dcb03617eb62e190ab4407e9f5da95408c1418f294e4bb35e46db42fbf79"
        },
        {
            "path":  "dist/stest.jpg",
            "sha256":  "68602ff5f85537f922b186ed58fb25316168e9c5d5d37a6bfa7c5f14de82ac07",
            "tlsh":  "8454232d75839b3497acc0ec32c275958f3c29b3f05dc61b8336b6744ea22179e99da1"
        },
        {
            "path":  "dist/decode.js",
            "sha256":  "6c38f6aea6e7951d53b92d7f947ece0d69a7114d1f4abf8d7196a6a21439f1a6",
            "tlsh":  "9a427c4cbd1a305bcb7ed3d336453395a1ac8a802b2e145cb27605e36fb3d8a95532ac"
        }
    ],
    "package_integrity":  [
        {
            "filename":  "esm-dotenv-1.0.1.tgz",
            "hashes":  {
                "sha1":  "e0413be76a0f39c3c0c6bf483bdd100e8da652ae",
                "sha512_sri":  "sha512-f3lZW/iPHV6Ggsh/Lt1qFqrtRyihg7SpK2hu9DnEd73m21OOcU3usLdR+pZLX6FSuqUWvp8YonlmHgc5TAkbKg=="
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/esm-dotenv/MAL-2026-17305.json"