ghsa-wfm5-v35h-vwf4
Vulnerability from github
Published
2023-08-29 23:33
Modified
2024-09-20 20:14
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.6 (High) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Summary
GitPython untrusted search path on Windows systems leading to arbitrary code execution
Details

Summary

When resolving a program, Python/Windows look for the current working directory, and after that the PATH environment (see big warning in https://docs.python.org/3/library/subprocess.html#popen-constructor). GitPython defaults to use the git command, if a user runs GitPython from a repo has a git.exe or git executable, that program will be run instead of the one in the user's PATH.

Details

This is more of a problem on how Python interacts with Windows systems, Linux and any other OS aren't affected by this. But probably people using GitPython usually run it from the CWD of a repo.

The execution of the git command happens in

https://github.com/gitpython-developers/GitPython/blob/1c8310d7cae144f74a671cbe17e51f63a830adbf/git/cmd.py#L277

https://github.com/gitpython-developers/GitPython/blob/1c8310d7cae144f74a671cbe17e51f63a830adbf/git/cmd.py#L983-L996

And there are other commands executed that should probably be aware of this problem.

PoC

On a Windows system, create a git.exe or git executable in any directory, and import or run GitPython from that directory

python -c "import git"

The git executable from the current directory will be run.

Impact

An attacker can trick a user to download a repository with a malicious git executable, if the user runs/imports GitPython from that directory, it allows the attacker to run any arbitrary commands.

Possible solutions

  • Default to an absolute path for the git program on Windows, like C:\\Program Files\\Git\\cmd\\git.EXE (default git path installation).
  • Require users to set the GIT_PYTHON_GIT_EXECUTABLE environment variable on Windows systems.
  • Make this problem prominent in the documentation and advise users to never run GitPython from an untrusted repo, or set the GIT_PYTHON_GIT_EXECUTABLE env var to an absolute path.
  • Resolve the executable manually by only looking into the PATH environment variable (suggested by @Byron)

[!NOTE] This vulnerability was reported via email, and it was decided to publish it here and make it public, so the community is aware of it, and a fix can be provided.

Show details on source website

To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.1.32"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "GitPython"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.33"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-40590"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-426"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-08-29T23:33:53Z",
    "nvd_published_at": "2023-08-28T18:15:08Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nWhen resolving a program, Python/Windows look for the current working directory, and after that the PATH environment (see big warning in https://docs.python.org/3/library/subprocess.html#popen-constructor). GitPython defaults to use the `git` command, if a user runs GitPython from a repo has a `git.exe` or `git` executable, that program will be run instead of the one in the user\u0027s `PATH`.\n\n### Details\n\nThis is more of a problem on how Python interacts with Windows systems, Linux and any other OS aren\u0027t affected by this. But probably people using GitPython usually run it from the CWD of a repo.\n\nThe execution of the `git` command happens in\n\nhttps://github.com/gitpython-developers/GitPython/blob/1c8310d7cae144f74a671cbe17e51f63a830adbf/git/cmd.py#L277 \n\nhttps://github.com/gitpython-developers/GitPython/blob/1c8310d7cae144f74a671cbe17e51f63a830adbf/git/cmd.py#L983-L996\n\nAnd there are other commands executed that should probably be aware of this problem.\n\n### PoC\n\nOn a Windows system, create a `git.exe` or `git` executable in any directory, and import or run GitPython from that directory\n\n```\npython -c \"import git\"\n```\n\nThe git executable from the current directory will be run.\n\n### Impact\n\nAn attacker can trick a user to download a repository with a malicious `git` executable, if the user runs/imports GitPython from that directory, it allows the attacker to run any arbitrary commands.\n\n### Possible solutions\n \n- Default to an absolute path for the git program on Windows, like `C:\\\\Program Files\\\\Git\\\\cmd\\\\git.EXE` (default git path installation).\n- Require users to set the `GIT_PYTHON_GIT_EXECUTABLE` environment variable on Windows systems.\n- Make this problem prominent in the documentation and advise users to never run GitPython from an untrusted repo, or set the `GIT_PYTHON_GIT_EXECUTABLE` env var to an absolute path.\n- Resolve the executable manually by only looking into the `PATH` environment variable (suggested by @Byron)\n\n---\n\n\u003e [!NOTE]\n\u003e This vulnerability was reported via email, and it was decided to publish it here and make it public, so the community is aware of it, and a fix can be provided.",
  "id": "GHSA-wfm5-v35h-vwf4",
  "modified": "2024-09-20T20:14:20Z",
  "published": "2023-08-29T23:33:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-wfm5-v35h-vwf4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-40590"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gitpython-developers/GitPython/issues/1635"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gitpython-developers/GitPython/pull/1636"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gitpython-developers/GitPython/commit/8b75434e2c8a082cdeb4971cc6f0ee2bafec45bc"
    },
    {
      "type": "WEB",
      "url": "https://docs.python.org/3/library/subprocess.html#popen-constructor"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/gitpython-developers/GitPython"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gitpython-developers/GitPython/releases/tag/3.1.33"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/gitpython/PYSEC-2023-161.yaml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "GitPython untrusted search path on Windows systems leading to arbitrary code execution"
}


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