MAL-2026-11107

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/num-format-helper/MAL-2026-11107.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-11107
Published
2026-07-28T07:15:58Z
Modified
2026-08-04T22:05:11.003045418Z
Summary
Malicious code in num-format-helper (npm)
Details

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

Source: amazon-inspector (04a0ecb436de3a0e93a577a3ba1733b227bd536e02acf371df530c6a320e1001)

Package advertises itself as a number/locale formatting helper but its postinstall.js runs automatically on npm install and shells out via childprocess/exec to collect host identity (hostname, user, id, sudo, uname), GitHub Actions variables including GITHUBTOKEN and GITHUBREPOSITORY, a broad env dump filtered by a credential regex (KEY|TOKEN|SECRET|CREDENTIAL|KUBE|JENKINS|NPM|GEM|CARGO|AZURE|GCP|AWS|GHTOKEN|GITHUBTOKEN), network interfaces, running processes, and cloud instance metadata (AWS 169.254.169.254, Aliyun 100.100.100.200, Tencent). The collected data is base64-encoded and sent via curl in a GET request to the hardcoded Burp Collaborator subdomain pzs5w7ntzhsnepwk564lyfdci3oucl0a.oastify.com. The shipped index.js is a trivial unrelated stub, confirming the package is a cover story for the install-time exfiltration payload.

Source: ossf-package-analysis (8a8aaefbf5f2df138b5dd99eeb8aa0247ffe7570759470e6ad7479fc0700345f)

The OpenSSF Package Analysis project identified 'num-format-helper' @ 1.0.0 (npm) as malicious.

It is considered malicious because:

  • The package communicates with a domain associated with malicious activity.

  • The package executes one or more commands associated with malicious behavior.

Database specific 
{
    "malicious-packages-origins": [
        {
            "import_time": "2026-07-28T07:26:58.386048285Z",
            "modified_time": "2026-07-28T07:15:58Z",
            "sha256": "8a8aaefbf5f2df138b5dd99eeb8aa0247ffe7570759470e6ad7479fc0700345f",
            "source": "ossf-package-analysis",
            "versions": [
                "1.0.0"
            ]
        },
        {
            "source": "amazon-inspector",
            "import_time": "2026-08-04T21:33:15.649367338Z",
            "sha256": "04a0ecb436de3a0e93a577a3ba1733b227bd536e02acf371df530c6a320e1001",
            "modified_time": "2026-08-04T21:27:30Z",
            "id": "IN-MAL-2026-011065",
            "versions": [
                "1.0.0"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / num-format-helper

Package

Name
num-format-helper
View open source insights on deps.dev
Purl
pkg:npm/num-format-helper

Affected ranges

Affected versions

1.*
1.0.0

Database specific

cwes 
[
    {
        "cweId": "CWE-506",
        "name": "Embedded Malicious Code",
        "description": "The product contains code that appears to be malicious in nature."
    }
]
indicators 
{
    "package_integrity": [
        {
            "filename": "num-format-helper-1.0.0.tgz",
            "hashes": {
                "sha512_sri": "sha512-bH45pBvfoz4awNCW7xNhMlCEoxBsfSRMAlw+HAUTcSvf5Be9cbb+0Ph0q+QRpbUf6+fJEN4kee64J9Xlf1R5Tg==",
                "sha1": "6866c13725327adb911d63fdd8f4339af40c5258"
            }
        }
    ],
    "evidence_files": [
        {
            "tlsh": "834189e8f619b834364dc4f8b68e55027893e9af89f4ff74553b4db0044c98820aab36",
            "sha256": "2f12974f8ceb206a773b9456efee5274e5bc739dc9d7436fdc7f0893ce61af82",
            "path": "postinstall.js"
        },
        {
            "tlsh": "8fe0c234e92596337dc497a90d9386063a310e4b12843d0926d71458938f6b694ffb1a",
            "sha256": "0c179333614beca723adf5554d2a96f1b8583bfe7755a204a98b1a06f3e9eddd",
            "path": "package.json"
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/num-format-helper/MAL-2026-11107.json"