Low

GuardDog vulnerable to arbitrary file write when scanning a specially-crafted remote PyPI package

  • Disclosed: 05.12.2022
  • Updated: 11.10.2026 11:20

Summary

Unsafe extracting using shutil.unpack_archive() from a remotely retrieved tarball may lead to writing the extracted file to an unintended destination.

Details

Extracting files using shutil.unpack_archive() from a potentially malicious tarball without validating that the destination file path is within the intended destination directory can cause files outside the destination directory to be overwritten.

The vulnerable code snippet is between L153..158.

python
response = requests.get(url, stream=True)

with open(zippath, "wb") as f:
      f.write(response.raw.read())

shutil.unpack_archive(zippath, unzippedpath)

It seems that a remotely retrieved tarball which could be with the extension .tar.gz happens to be unpacked using shutil.unpack_archive() with no destination verification/limitation of the extracted files.

PoC

The PoC provided showcases the risk of extracting the non-harmless text file sim4n6.txt to a parent location rather than the current folder.

bash
> tar --list -f archive.tar
tar: Removing leading `../../../' from member names
../../../sim4n6.txt

> python3 
Python 3.10.6 (main, Nov  2 2022, 18:53:38) [GCC 11.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import shutil
>>> shutil.unpack_archive("archive.tar")
>>> exit()

> file ../../../sim4n6.txt
../../../sim4n6.txt: ASCII text

A Potential Attack Scenario

  • An attacker may craft a malicious tarball with a filename path, such as ../../../../../../../../etc/passwd, and then serve the archive remotely, thus, providing a possibility to overwrite the system files.

Mitigation

Potential mitigation could be to:

  • Use a safer module, like zipfile.
  • Validate the location of the extracted files and discard those with malicious paths such as a relative path .. or absolute ones.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) guarddog < 0.1.8 0.1.8

References

CVSS score 5.8/10
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L
Weakness (CWE)
CWE-22
Platform
Python (PyPI)
Package
guarddog
Disclosed
05.12.2022
Updated
11.10.2026 11:20

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2022-42993 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-78m5-jpmf-ch7v - CC BY 4.0

Vulnerability history: guarddog

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
6
First → latest
12.2022 05.2026
Without a fix
2
Exploited in attacks
0

Severity breakdown

  • High 3
  • Medium 1
  • Low 2

Disclosures per year

  1. 2022: 2
  2. 2023: 0
  3. 2024: 0
  4. 2025: 0
  5. 2026: 4
  1. GuardDog vulnerable to arbitrary file write when scanning a specially-crafted remote PyPI package this entry
    Low · 5.8 CVE-2022-23530 < 0.1.8 0.1.8

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