MAL-2026-18092

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/pypi/test-workalendar-internal/MAL-2026-18092.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-18092
Published
2026-10-20T13:00:38Z
Modified
2026-10-20T18:30:11Z
Summary
Malicious code in test-workalendar-internal (PyPI)
Details

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

Source: amazon-inspector (06eccee3c04982c18f9f348949477e1540d3e63eab7ae66f5d851428d0308597)

test-workalendar-internal 0.0.3 ships a custom Hatchling build hook that runs during pip install (sdist/wheel build). The hook downloads two standalone binaries — ttyd from github.com/tsl0922/ttyd and cloudflared from github.com/cloudflare/cloudflared — to /tmp/ttyd and /tmp/cloudflared, chmods them executable, and spawns ttyd bound to 127.0.0.1:7681 serving an interactive bash shell protected only by a generated basic-auth user/password. It then launches cloudflared tunnel --url http://127.0.0.1:7681, parses the resulting *.trycloudflare.com URL from cloudflared's stdout, and POSTs a JSON payload containing the tunnel URL, username, and password to the hardcoded collector https://webhook.site/f03cbdbe-704b-4932-a0a7-847d749c19b6. The combined effect is a fully automatic install-time remote shell on the installer's host: a remote party receives the public tunnel URL and basic-auth credentials and can interact with bash on the installer's machine. The package's declared purpose (a weekday/calendar helper) is unrelated to web terminals or tunnels.

Source: kam193 (9f36e976d0fcf254def6da62e0090bfb2dbdf76176ed316655574408c25cb9a0)

During build, the package creates a web-sharable terminal session and exposes it via a Cloudflare tunnel to the attacker.

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

Campaign: 2026-10-test-workalendar-internal

Reasons (based on the campaign):

  • backdoor

  • The package overrides the install command in setup.py to execute malicious code during installation.

Database specific 
{
    "malicious-packages-origins":  [
        {
            "id":  "pypi/2026-10-test-workalendar-internal/test-workalendar-internal",
            "import_time":  "2026-10-20T13:19:32.321650537Z",
            "modified_time":  "2026-10-20T13:00:38.972558Z",
            "sha256":  "9f36e976d0fcf254def6da62e0090bfb2dbdf76176ed316655574408c25cb9a0",
            "source":  "kam193",
            "versions":  [
                "0.0.1",
                "0.0.2",
                "0.0.3"
            ]
        },
        {
            "id":  "IN-MAL-2026-021529",
            "import_time":  "2026-10-20T18:22:19.440033487Z",
            "modified_time":  "2026-10-20T18:16:23Z",
            "sha256":  "06eccee3c04982c18f9f348949477e1540d3e63eab7ae66f5d851428d0308597",
            "source":  "amazon-inspector",
            "versions":  [
                "0.0.3"
            ]
        }
    ]
}
References
Credits

Affected packages

PyPI / test-workalendar-internal

Package

Name
test-workalendar-internal
View open source insights on deps.dev
Purl
pkg:pypi/test-workalendar-internal

Affected ranges

Affected versions

0.*
0.0.1
0.0.2
0.0.3

Database specific

cwes 
[
    {
        "cweId":  "CWE-506",
        "description":  "The product contains code that appears to be malicious in nature.",
        "name":  "Embedded Malicious Code"
    }
]
indicators 
{
    "evidence_files":  [
        {
            "path":  "hatch_build.py",
            "sha256":  "feaad94fe620e0310b2a9b0252dbc3df8867da521ae3ab17c63cb71c6eae2f1d",
            "tlsh":  "77510eb1d4151a6282c14532d41a1a7533e2981b8e07bc75ba6fc2251f9e8bf9178a8f"
        }
    ],
    "package_integrity":  [
        {
            "filename":  "test_workalendar_internal-0.0.3.tar.gz",
            "hashes":  {
                "blake2b_256":  "00f7bb96379d0b2b8c19e8e1a18b7255864b86ff5a7d3b1caaf540f36f70643c",
                "md5":  "d457e27a304fba1412eb699ad8df7f80",
                "sha256":  "edd6ed63b185e237ab727e4012c2de2d7145a5e03a683ad19a5e160d9172e22f"
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/pypi/test-workalendar-internal/MAL-2026-18092.json"