Sandex (Sandboxed Extractor)

CLI tool for extracting files in a sandbox.
Only available for Linux.

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Dependencies

• bubblewrap (bwrap) — sandboxing
  https://github.com/containers/bubblewrap

• bsdtar — ZIP and TAR extraction
  https://github.com/libarchive/libarchive

• unrar — RAR extraction
  https://github.com/aawc/unrar

• python — Orchestration (version >= 3.10)

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Installation

1. Ensure that you have the dependencies listed earlier
2. Download a wheel from releases.
3. Run python -m installer --prefix="$HOME/.local" <path to wheel> to install as user (no need for SUDO)
4. Follow the usage guide below to start extracting files

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Usage

Basic extraction:

sandex archive_path

Extracts the given archive into its parent directory.
The extracted folder name defaults to the archive filename without its suffix.

Example:

sandex samples.zip

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Specify output directory:

sandex archive_path --out output_directory

Example:

sandex samples.tar.gz --out /tmp

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Specify extracted folder name:

sandex archive_path --name folder_name

Example:

sandex samples.zip --name extracted_samples

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Combine options:

sandex archive_path --out output_directory --name folder_name

Example:

sandex samples.rar --out /tmp --name test_run

Output

On success, sandex prints the full path of the final extraction directory to stdout.

On failure, a Python traceback is printed and the process exits with status code 1.

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Exit codes

• 0 — success
• 1 — failure

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Synopsis

sandex [--version] ARCHIVE [--out DIR] [--name NAME]

Arguments

• ARCHIVE — path to archive file (required)
• --out — output directory (default: archive parent directory)
• --name — extracted folder name (default: archive name without suffix)

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Sandbox configuration

All of the following points apply to the sandbox defaults

1. unshare-net : Creates a new network namespace, isolating the process from the host's one. Because no other network is provided the process cannot access the internet.
2. unshare-pid : Creates a new process namespace, preventing the sandbox from seeing host processes.
3. die-with-parent : Ensures process tree is killed if parent dies. Prevents orphaned sandbox processes.
4. ro-bind : Both the archive to extract and needed binaries (/usr, /bin, /lib, ... ) are mounted as read only, preventing writes to those paths while allowing execution of tools.
5. bind : Allows only writes to the extraction directory. These are some of the flags, for more details on how the sandbox is configured, see sandbox.py.

Why?

Extracting untrusted files is always unsafe, sandex is a way to limit the blast radius. Here are some examples of relevant security vulnerabilities of extractors:

1. CVE-2025-45582 GNU Tar 1.35: Attackers were able to write to critical system files via symlinks, after the user extracts a tar. https://nvd.nist.gov/vuln/detail/CVE-2025-45582
2. CVE-2025-55188 7Zip : Same symlink things. https://nvd.nist.gov/vuln/detail/CVE-2025-55188

Many archive-related issues fall under the “Zip Slip” class (path traversal and symlink abuse). Sandex mitigates these by restricting writable paths to the extraction directory and isolating the extraction process using Linux namespaces.

Future versions will support:

• Sandboxing overrides
• Profile creation