MAL-2026-6557

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/pypi/pkg-fallback/MAL-2026-6557.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-6557
Published
2026-06-28T06:01:28Z
Modified
2026-06-28T08:15:56Z
Summary
Malicious code in pkg-fallback (PyPI)
Details

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

Source: amazon-inspector (7f4ccaa9f059318782cd3b811f5bd6ea926e267e4b05dc4971d6acc6687d5d4f)

setup.py performs an unconditional urllib.request.urlopen() at install time to a hardcoded plaintext bare-IP endpoint http://157.254.194.200:8080/dependency-payload-1.0.0.tar.gz, with exceptions silently swallowed. This fires automatically during pip install (build/setup phase), confirming code execution on the installer's machine and disclosing the installer's network identity to attacker-controlled infrastructure. The distribution is published as 'pkg-fallback' but ships an unrelated 'string_kit' module described as 'string-kit' in README/PKG-INFO; the name/module divergence together with the install-time bare-IP beacon and the attacker-suggestive payload filename ('dependency-payload') is consistent with a dependency-confusion staging/enumeration package rather than a genuine utility.

Source: kam193 (4563c95d80446cbc0c815185ab9b3649b048c82a33b2d662523ce4760dbc6856)

Package exploits dependency confusion. A beacon request is used to report usage back, but no additional information are exfiltrated.

Category: PROBABLY_PENTEST - Packages looking like typical pentest packages, but also anything that looks like testing, exploring pre-prepared kits, research & co, with clearly low-harm possibilities.

Campaign: GENERIC-beacon-dependency-confusion

Reasons (based on the campaign):

  • typosquatting

  • dependency-confusion

Database specific 
{
    "malicious-packages-origins":  [
        {
            "id":  "IN-MAL-2026-007697",
            "import_time":  "2026-06-28T06:50:42.931191475Z",
            "modified_time":  "2026-06-28T06:01:28Z",
            "ranges":  [
                {
                    "events":  [
                        {
                            "introduced":  "0"
                        }
                    ],
                    "type":  "ECOSYSTEM"
                }
            ],
            "sha256":  "7f4ccaa9f059318782cd3b811f5bd6ea926e267e4b05dc4971d6acc6687d5d4f",
            "source":  "amazon-inspector",
            "versions":  [
                "1.1.0"
            ]
        },
        {
            "id":  "pypi/GENERIC-beacon-dependency-confusion/pkg-fallback",
            "import_time":  "2026-06-28T08:10:57.722648683Z",
            "modified_time":  "2026-06-28T07:22:27.366925Z",
            "sha256":  "4563c95d80446cbc0c815185ab9b3649b048c82a33b2d662523ce4760dbc6856",
            "source":  "kam193",
            "versions":  [
                "1.1.0"
            ]
        }
    ]
}
References
Credits

Affected packages

PyPI / pkg-fallback

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.1.0

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":  "setup.py",
            "sha256":  "e63cda868cf61706d3d8666c109977ecbcbc7b83f0d784a0330a4196bf034822",
            "tlsh":  "6901ce85ce8078e5c9dba64548799c5e12326b033d01f4d9bb8983583f4d2dfcb36259"
        }
    ],
    "package_integrity":  [
        {
            "filename":  "pkg_fallback-1.1.0.tar.gz",
            "hashes":  {
                "blake2b_256":  "bfdd6c973cf80595a3f50e4d3e2c19dff3f72fda1ec86eb37689573bae86a5a9",
                "md5":  "6f78fa86c4f5c320aec88febbcd47878",
                "sha256":  "272ff22462e20ef5fd5766729843adfc577ff8a72c6c87e809c56efc6e042921"
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/pypi/pkg-fallback/MAL-2026-6557.json"