MAL-2026-3836

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/ctf-flare/MAL-2026-3836.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-3836
Published
2026-05-18T11:54:34Z
Modified
2026-05-26T06:02:27.277064157Z
Summary
Malicious code in ctf-flare (npm)
Details

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

Source: amazon-inspector (23293f1bc28e465f7ffaf916fd8a6cc3958b873a2b338b81c0bf71bb146d1d36)

package.json declares a postinstall script that runs node src/install.js after building a local binary. src/install.js is a 175 KB single-line payload obfuscated with a Function(...) constructor wrapper, LZString-compressed UTF-16 string tables, and per-helper rotated base85 alphabets. Once de-obfuscated, the payload resolves the strings child_process, node-fetch/fetch, -c, shell, detached, stdio, ignore, performs an outbound fetch(url, {headers:...}), reads the response body, and passes it to require('child_process').spawn('sh', ['-c', <fetched-body>], {shell, detached, stdio:'ignore'}). This fires unattended on npm install and runs attacker-controlled shell content with the installer's privileges. The multi-layer obfuscation (Function-constructor + LZString + rotated alphabets + global rebinding through aliased getters such as FTecFy['G9V6x7'] === require) exists solely to hide the fetch-and-exec from scanners and reviewers; legitimate install tooling does not need that. The shipped bin/flare binary built by make is a local CTF-style reverse-engineering challenge (ptrace anti-debug, hardcoded magic constants, XOR-decoded flag string) and is not the installer-harm vector — the dropper in src/install.js is. The CTF framing in the README does not neutralize the install-time RCE: any developer running npm install ctf-flare executes whatever shell text the remote endpoint serves at that moment.

Source: ossf-package-analysis (1e0cd8fbb0f9460f4c76a5479edc1354e5cd16fcee1929e83a3c1122ebbd1513)

The OpenSSF Package Analysis project identified 'ctf-flare' @ 1.0.0 (npm) as malicious.

It is considered malicious because:

  • The package executes one or more commands associated with malicious behavior.
Database specific 
{
    "malicious-packages-origins": [
        {
            "versions": [
                "1.0.0"
            ],
            "sha256": "1e0cd8fbb0f9460f4c76a5479edc1354e5cd16fcee1929e83a3c1122ebbd1513",
            "source": "ossf-package-analysis",
            "modified_time": "2026-05-18T11:54:34Z",
            "import_time": "2026-05-19T00:55:38.328675287Z"
        },
        {
            "import_time": "2026-05-19T17:50:38.972849905Z",
            "sha256": "6d3d33b0a8806af9f1221e16d5c40b2156e9622753b976f62098f282ae64001f",
            "source": "amazon-inspector",
            "modified_time": "2026-05-19T16:47:48Z",
            "versions": [
                "1.0.0"
            ]
        },
        {
            "id": "IN-MAL-2026-003469",
            "versions": [
                "1.0.0"
            ],
            "sha256": "23293f1bc28e465f7ffaf916fd8a6cc3958b873a2b338b81c0bf71bb146d1d36",
            "source": "amazon-inspector",
            "modified_time": "2026-05-20T05:18:25Z",
            "import_time": "2026-05-26T05:50:42.148649481Z"
        }
    ]
}
References
Credits

Affected packages

npm / ctf-flare

Package

Name
ctf-flare
View open source insights on deps.dev
Purl
pkg:npm/ctf-flare

Affected ranges

Affected versions

1.*
1.0.0

Database specific

cwes 
[
    {
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code",
        "cweId": "CWE-506"
    }
]
indicators 
{
    "evidence_files": [
        {
            "path": "src/install.js",
            "sha256": "d32e8f6e1c6541d30167801a040af853d845097df22515e1fc168a4a3d477cc4",
            "tlsh": "220453960eb11759b3de4b008e36ed4c10ac673a5f4874ceaff3e5f6a64cd564ae0a01"
        },
        {
            "path": "src/main.c",
            "sha256": "857564c9b45635b4c79159cf517d17b23ed6dd13472ac2c1e7b283ce1c50ff35",
            "tlsh": "11e163552ea240e319979b7b938b51479318a02733a0fcd1f88fa54c9f83215e3b6ed4"
        }
    ],
    "package_integrity": [
        {
            "filename": "ctf-flare-1.0.0.tgz",
            "hashes": {
                "sha512_sri": "sha512-XrLqWJBPbk1p6Z+dEQKaa1vscFdajbkZ71sk26URkLrVHg7ZU8d65yEhMw3MhhdIQKqUa12qoy4DjHT8DIwu9w==",
                "sha1": "2cddaa74963256ae56d1f7a144c38a5343266fc2"
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/ctf-flare/MAL-2026-3836.json"