MAL-2026-16264

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Import Source

https://github.com/ossf/malicious-packages/blob/main/osv/malicious/pypi/aiosendletter/MAL-2026-16264.json

JSON Data

https://api.osv.dev/v1/vulns/MAL-2026-16264

Published

2026-09-17T19:40:07Z

Modified

2026-09-18T01:00:06Z

Summary

Malicious code in aiosendletter (PyPI)

Details

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

Source: amazon-inspector (29baa6f2cbfb2ef9907be7830505e33e82b5a1e6a45eb7f995022d09f5841f09)

The package advertises itself as a 'safe bug reporter' but its init() function archives the contents of %LOCALAPPDATA%\logs with shutil.make_archive and POSTs the resulting archive to a hardcoded, non-configurable Cloudflare Workers endpoint at https://sparkling-pine-f202.stilluer-sweden.workers.dev/. The destination is author-controlled, the caller has no way to redirect or disable it, and code comments indicate the target directory is expected to include a Telegram bot token folder — the collected data is credential-adjacent local state leaving the installer's machine. On Windows the same function calls ctypes.windll.shell32.ShellExecuteW with the 'runas' verb to relaunch the interpreter under UAC elevation before performing the archive-and-upload, broadening the set of files reachable for collection. Separately, pyproject.toml declares 'ctypes' as a runtime dependency; ctypes is a Python standard-library module, so pip resolves this name against PyPI and installs whatever package is published there under 'ctypes', executing that third party's code at install time. The cover-story description, the hardcoded off-host destination for locally-collected data, the privilege escalation, and the stdlib-name dependency-confusion vector jointly constitute an active supply-chain attack on installers.

Source: kam193 (4e81e3b63bbe719f6d0bdd42930bb2f3235b8e41cbacf449743bb7dca67c9f08)

Package hides code to exfiltrate files. Most releases target unclear files, but some reveal the goal to exfiltrate sensitive Telegram data.

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

Campaign: 2026-09-aiosendletter

Reasons (based on the campaign):

files-exfiltration
target:telegram

Database specific

{
    "iocs": {
        "domains": [
            "sparkling-pine-f202.stilluer-sweden.workers.dev"
        ]
    },
    "malicious-packages-origins": [
        {
            "id": "pypi/2026-09-aiosendletter/aiosendletter",
            "import_time": "2026-09-17T20:18:46.828650231Z",
            "modified_time": "2026-09-17T19:40:07.407033Z",
            "sha256": "4e81e3b63bbe719f6d0bdd42930bb2f3235b8e41cbacf449743bb7dca67c9f08",
            "source": "kam193",
            "versions": [
                "0.2.0",
                "3.7",
                "3.8",
                "3.9",
                "4.0",
                "4.1",
                "4.3",
                "4.5",
                "4.6"
            ]
        },
        {
            "id": "IN-MAL-2026-020143",
            "import_time": "2026-09-17T23:14:58.759955665Z",
            "modified_time": "2026-09-17T23:14:39Z",
            "sha256": "26f8a892e736700361508bf143cc8a5eeeb0c929ee01301b9bf336fbdeb90f90",
            "source": "amazon-inspector",
            "versions": [
                "4.3"
            ]
        },
        {
            "id": "IN-MAL-2026-020142",
            "import_time": "2026-09-17T23:14:58.664583978Z",
            "modified_time": "2026-09-17T23:14:31Z",
            "sha256": "46b706e618e75dd4f864a55a33a06cfa98c890d310735b1dea71ad86fe299fe6",
            "source": "amazon-inspector",
            "versions": [
                "4.6"
            ]
        },
        {
            "id": "IN-MAL-2026-020144",
            "import_time": "2026-09-18T00:47:15.339356629Z",
            "modified_time": "2026-09-17T23:14:47Z",
            "sha256": "6884846406ab88650e3956042749971d67d8188a37d72d24f4b8f263d98e4854",
            "source": "amazon-inspector",
            "versions": [
                "3.8"
            ]
        },
        {
            "id": "IN-MAL-2026-020145",
            "import_time": "2026-09-18T00:47:15.384346644Z",
            "modified_time": "2026-09-17T23:14:56Z",
            "sha256": "9e3d0073fb12cbc28fff838b3f6e7ee9e911fe2450f36a9f9be2bea1d8ad0ebf",
            "source": "amazon-inspector",
            "versions": [
                "4.5"
            ]
        },
        {
            "id": "IN-MAL-2026-020147",
            "import_time": "2026-09-18T00:47:15.532427115Z",
            "modified_time": "2026-09-17T23:15:19Z",
            "sha256": "cc1e887b4a68047c0bbd0d4eb68247ee2854f6f5e7d81ce9e662bbcb7af774fc",
            "source": "amazon-inspector",
            "versions": [
                "3.9"
            ]
        },
        {
            "id": "IN-MAL-2026-020150",
            "import_time": "2026-09-18T00:47:15.745998382Z",
            "modified_time": "2026-09-17T23:15:52Z",
            "sha256": "01b07e00c5b992edefe41ae2a09e7718cee87521d2fb6ede5c44810857d2f2c4",
            "source": "amazon-inspector",
            "versions": [
                "0.2.0"
            ]
        },
        {
            "id": "IN-MAL-2026-020149",
            "import_time": "2026-09-18T00:47:15.653536734Z",
            "modified_time": "2026-09-17T23:15:41Z",
            "sha256": "29baa6f2cbfb2ef9907be7830505e33e82b5a1e6a45eb7f995022d09f5841f09",
            "source": "amazon-inspector",
            "versions": [
                "3.7"
            ]
        },
        {
            "id": "IN-MAL-2026-020146",
            "import_time": "2026-09-18T00:47:15.455634902Z",
            "modified_time": "2026-09-17T23:15:06Z",
            "sha256": "2e4a3c82f1ac4949f224b2e19558ea52828b59163a4039f5a9cf211243275738",
            "source": "amazon-inspector",
            "versions": [
                "4.1"
            ]
        },
        {
            "id": "IN-MAL-2026-020148",
            "import_time": "2026-09-18T00:47:15.570339329Z",
            "modified_time": "2026-09-17T23:15:30Z",
            "sha256": "683ec28918276f869973aaccf51bebc21a0435c3e059d631c5d40fac4e3aef53",
            "source": "amazon-inspector",
            "versions": [
                "4.0"
            ]
        }
    ]
}

References

Credits

- Amazon Inspector - FINDER
- - inspector-research@amazon.com
- Kamil Mańkowski (kam193) - REPORTER
- - https://github.com/kam193
  - https://bad-packages.kam193.eu/

Affected packages

PyPI / aiosendletter

Package

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

Affected ranges

Affected versions

0.*

0.2.0

3.*

3.7

3.8

3.9

4.*

4.0

4.1

4.3

4.5

4.6

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"
    },
    {
        "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"
    },
    {
        "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": "aiosendletter/__init__.py",
            "sha256": "3f23bbb7634976c0200c579568350be83f06fccc2a4d75377fb7f286db6e98d7",
            "tlsh": "5e5154469c89105a5071e94c9c11d58cf94a82bf3fa701b77edc09253ff0475e3b0254"
        },
        {
            "path": "pyproject.toml",
            "sha256": "d32424873e738826d4de8e5b9753f280cda4642f22bcaa1635b83182353319b9",
            "tlsh": "0fe0ab7387dbac149952228058280350faa1902825184026a7dfc2ce12d74e9dbecc31"
        }
    ],
    "package_integrity": [
        {
            "filename": "aiosendletter-4.3-py3-none-any.whl",
            "hashes": {
                "blake2b_256": "2eea089903f1cfe02e63e606c8109cb71aacf7c936c657856a2cce1aefb1ecd5",
                "md5": "6bdb17c75770d34262072543b104c441",
                "sha256": "e674aae1abab6e58238801186b0b159baebd1a19e799591fc943999cf0bbdde5"
            }
        },
        {
            "filename": "aiosendletter-4.3.tar.gz",
            "hashes": {
                "blake2b_256": "ecb2368e27685be185f5565348e7facd3d97de6de8420e35405c534c55732a09",
                "md5": "f81bca5b232606dbddd98bb401dc1cfc",
                "sha256": "e5c6b0f3f045c3da3a1de43580dfd62e0bfbb0faee98a61cfad77342bef16977"
            }
        }
    ]
}

source

"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/pypi/aiosendletter/MAL-2026-16264.json"