MAL-2026-4227

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/pypi/lognest/MAL-2026-4227.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-4227
Published
2026-05-21T14:18:26Z
Modified
2026-05-26T06:03:12Z
Summary
Malicious code in lognest (PyPI)
Details

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

Source: amazon-inspector (481f45cde243009853b52b584fb6a1af2eae31e637912c8b78f18a8d7ee0d9d0)

On import lognest, the package's init.py spawns a detached background subprocess running a sibling _check.py (lognest/init.py:25 subprocess.Popen([sys.executable, os.path.join(base_dir, "_check.py")], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)). That script enters an infinite loop POSTing to https://pypkg.dev/project/logger/json — a lookalike of pypi.org — with TLS verification explicitly disabled via ssl._create_unverified_context() (lognest/_check.py:22). On the first request it exfiltrates the absolute install path (Path(__file__).resolve().parent) which typically encodes the installer's username, virtualenv layout, or CI runner path (lognest/_check.py:18). Server responses are base64-decoded and dispatched on background threads (lognest/_check.py:31), giving the operator a persistent C2 channel for delivering second-stage payloads to any process that imports the package. None of this behavior matches the package's advertised purpose as a logger. The combination of import-time background process, lookalike non-publisher host, TLS-disable, install-path exfiltration, and base64-decoded response dispatch is an unambiguous attacker-controlled remote-execution channel.

Source: kam193 (8a52e16511fcccbee8bfd9e44dca8d6a3b5927bd5e66cf6fc7b849900c71ed9f)

Package silently executes remote code during import.

Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.

Campaign: 2026-05-lognest

Reasons (based on the campaign):

  • Downloads and executes a remote malicious script.
Database specific 
{
    "iocs": {
        "domains": [
            "pypkg.dev"
        ],
        "urls": [
            "https://pypkg.dev/project/logger/json"
        ]
    },
    "malicious-packages-origins": [
        {
            "id": "pypi/2026-05-lognest/lognest",
            "import_time": "2026-05-21T17:24:41.679520582Z",
            "modified_time": "2026-05-21T16:13:53.9023Z",
            "sha256": "8a52e16511fcccbee8bfd9e44dca8d6a3b5927bd5e66cf6fc7b849900c71ed9f",
            "source": "kam193",
            "versions": [
                "0.1.0",
                "0.1.1",
                "0.1.2",
                "0.1.3",
                "0.1.4"
            ]
        },
        {
            "id": "IN-MAL-2026-003865",
            "import_time": "2026-05-26T05:51:28.514632828Z",
            "modified_time": "2026-05-21T14:18:26Z",
            "sha256": "8bf5b7affdac26cee7e47cb0c56901faeb02d82c49aa5fb7b1f868b83a9d3fd5",
            "source": "amazon-inspector",
            "versions": [
                "0.1.2"
            ]
        },
        {
            "id": "IN-MAL-2026-003866",
            "import_time": "2026-05-26T05:51:28.694020713Z",
            "modified_time": "2026-05-21T14:18:46Z",
            "sha256": "1e3cfa27d08fbc958fff6e818a6ea1b9c36dce3c695a115fa40e5199fe4b87aa",
            "source": "amazon-inspector",
            "versions": [
                "0.1.1"
            ]
        },
        {
            "id": "IN-MAL-2026-003874",
            "import_time": "2026-05-26T05:51:29.639551003Z",
            "modified_time": "2026-05-21T15:18:51Z",
            "sha256": "481f45cde243009853b52b584fb6a1af2eae31e637912c8b78f18a8d7ee0d9d0",
            "source": "amazon-inspector",
            "versions": [
                "0.1.3"
            ]
        }
    ]
}
References
Credits

Affected packages

PyPI / lognest

Package

Name
lognest
View open source insights on deps.dev
Purl
pkg:pypi/lognest

Affected ranges

Affected versions

0.*
0.1.0
0.1.1
0.1.2
0.1.3
0.1.4

Database specific

cwes 
[
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    },
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    },
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    }
]
indicators 
{
    "evidence_files": [
        {
            "path": "lognest/_check.py",
            "sha256": "23ab0bb61ba5774786fe04c4881d5a899d7ac78b8fb7f6a8dd9e788ca71fa93c",
            "tlsh": "85114416a82c00d5e387494ad411bb142337fc0f6342c2b0feac93e40fc857281f3146"
        },
        {
            "path": "lognest/__init__.py",
            "sha256": "9dd16d837ce61afa1dff11455e7788bfc02242657cd7caec7922f1e61109f02a",
            "tlsh": "6d01c0aa871f2166415ec6a8600707202792c5c7df0680f471dca3b82f8b97b15dd46d"
        }
    ],
    "package_integrity": [
        {
            "filename": "lognest-0.1.2-py3-none-any.whl",
            "hashes": {
                "blake2b_256": "e93600169d01ebb3fbbc2431d90c0c77cd55833e8bb9ed92f61528b5ce53f113",
                "md5": "c22d43636f8071ca64ec1b55861fcb65",
                "sha256": "337ed7b24acffe7479097a3bd646595d7cb4932975686ff70aec7d9bdcf0fef4"
            }
        },
        {
            "filename": "lognest-0.1.2.tar.gz",
            "hashes": {
                "blake2b_256": "cd44a81bbcc39d896caafb2d512280e5f7683260564a1cdc24e18fdd96ad47f7",
                "md5": "36cf3da9e2c81a3e9754c454936df112",
                "sha256": "4394e5f9b23ca6570f818ee72fb7908786f794c26d7c25308671c4aee1de5522"
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/pypi/lognest/MAL-2026-4227.json"