MAL-2026-5900

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/chai-as-decrypted/MAL-2026-5900.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-5900
Published
2026-06-16T16:18:25Z
Modified
2026-06-16T18:16:52.838196273Z
Summary
Malicious code in chai-as-decrypted (npm)
Details

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

Source: amazon-inspector (3ed93b06c95c42e3183b89e5fb1d9dea3f711bb20d766861c8d16b8d17f17cc9)

Package name chai-as-decrypted mimics the popular chai-as-promised, and the README impersonates pino (uses pino's npm badges and links to github.com/pinojs/pino). On npm install, the postinstall hook runs npm run smoke:pino → node./index.js, whose top-level runBackgroundTask() spawns a detached node lib/initializeCaller.js. That file shadows the global process with a local object whose env.DEV_API_KEY is a base64 string; it atob-decodes the value to https://www.ipregionchecker.org/api/ip-check-encrypted/3aeb34a37, POSTs to it via axios, and executes the HTTP response body with new Function.constructor("require", response)(require) — arbitrary remote JavaScript run with full require access on the installer's machine, retried 5 times. The base64 hiding of the endpoint and headers behind a fake process.env has no legitimate purpose and is solely to evade static scanners. This is a deliberate install-time remote code execution attack against developers who mistype chai-as-promised.

Database specific 
{
    "malicious-packages-origins": [
        {
            "versions": [
                "4.2.8"
            ],
            "modified_time": "2026-06-16T16:18:25Z",
            "sha256": "3ed93b06c95c42e3183b89e5fb1d9dea3f711bb20d766861c8d16b8d17f17cc9",
            "id": "IN-MAL-2026-006785",
            "source": "amazon-inspector",
            "import_time": "2026-06-16T18:10:20.278156633Z"
        }
    ]
}
References
Credits

Affected packages

npm / chai-as-decrypted

Package

Name
chai-as-decrypted
View open source insights on deps.dev
Purl
pkg:npm/chai-as-decrypted

Affected ranges

Affected versions

4.*
4.2.8

Database specific

cwes 
[
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    }
]
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/chai-as-decrypted/MAL-2026-5900.json"
indicators 
{
    "package_integrity": [
        {
            "filename": "chai-as-decrypted-4.2.8.tgz",
            "hashes": {
                "sha512_sri": "sha512-ypl31L0qfwb9j7U8dPIvLFDeMgiX9mQVvZfkKP/xhGtSG+yGHRr9cgNkCf3/ut/5uVgPOuisWZvtpl0h75YsNA==",
                "sha1": "06ac394a2a86b83fa30350c17879a1c85fd27d3e"
            }
        }
    ],
    "evidence_files": [
        {
            "path": "lib/initializeCaller.js",
            "tlsh": "4d119c4d71f82008042151e5b62f14126025e4673d8ad5e4bacc834b1fa667fbd53adf",
            "sha256": "76ca537732f161ae4d3a78b876390ddbab16e001c392a74009b31fb91ce4f89b"
        },
        {
            "path": "package.json",
            "tlsh": "5301cb20debc4e2305ed15860c2a06037a615d175928fc2833e7922c0f9d5fb40ff21e",
            "sha256": "566b1f7f56ac9149ff4381812ea8ee13e8b1a4c6512027996bddc19149f17b44"
        }
    ]
}