dll-downloader 1.1.0

A Python script to automatically search and download DLL files

DLL-Downloader

Search, download, and optionally scan DLL files with VirusTotal

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Overview

DLL-Downloader is a Python tool that searches and downloads DLL files from trusted sources and can optionally scan them using VirusTotal. It works as both a CLI tool and a Python library.

Key Features

Feature	Description
Search & Download	Resolve DLL names and download the correct file
ZIP Extraction	Optionally extract the DLL when the source returns a ZIP
Architecture Support	x86 and x64 downloads with PE architecture validation
VirusTotal Scan	Optional security scan before saving
Batch Mode	Download many DLLs from a file
Library Mode	Use the downloader directly from Python
Clean Architecture	Domain/use-case/infrastructure separation

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Installation

From PyPI (Recommended)

pip install dll-downloader

From Source

git clone https://github.com/seifreed/DLL-Downloader.git
cd DLL-Downloader
python3 -m venv venv
source venv/bin/activate  # Windows: venv\Scripts\activate
pip install -e .

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Configuration

You can configure settings using .config.json, environment variables, or ~/.vt.toml.

JSON config (.config.json)

{
  "virustotal_api_key": "your_virustotal_api_key_here",
  "download_directory": "./downloads",
  "download_base_url": "https://es.dll-files.com",
  "http_timeout": 60,
  "virustotal_timeout": 60.0,
  "verify_ssl": true,
  "scan_before_save": true,
  "malicious_threshold": 5,
  "suspicious_threshold": 1,
  "log_level": "INFO",
  "user_agent": null
}

VirusTotal key via ~/.vt.toml

apikey="your_virustotal_api_key_here"

Environment variables

export DLL_VIRUSTOTAL_API_KEY="your_virustotal_api_key_here"
export DLL_DOWNLOAD_DIRECTORY="./downloads"
export DLL_VIRUSTOTAL_TIMEOUT="60"

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Quick Start

# Download a single DLL
python3 dll-downloader.py msvcp140.dll

# Download x86 and fail if the source does not provide a matching PE DLL
python3 dll-downloader.py msvcp140.dll --arch x86

# Download and extract when the source returns a ZIP
python3 dll-downloader.py msvcp140.dll --extract

# Download from a list
python3 dll-downloader.py --file dll_list.txt

# Emit machine-readable JSON
python3 dll-downloader.py msvcp140.dll --json

# Emit SARIF for CI/security pipelines
python3 dll-downloader.py msvcp140.dll --sarif

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Usage

Command Line Interface

python3 dll-downloader.py <dll_name> [options]

Available Options

Option	Description
--file	File with one DLL name per line
--arch	Target architecture (x86 or x64; default: x64)
--debug	Enable debug output
--no-scan	Skip VirusTotal scan
--force	Force download even if cached
--output-dir	Custom output directory
--extract	Extract the DLL when the download is a ZIP archive
--json	Emit machine-readable JSON output
--sarif	Emit SARIF v2.1.0 output

Some providers return the DLL inside a ZIP archive. By default, dll-downloader expects the payload to be a real ZIP and validates that it contains a valid PE DLL. Without --extract, the validated ZIP is saved as-is. With --extract, the tool saves the unpacked .dll, which is useful in CI/CD workflows. If the payload is not a valid ZIP or the embedded DLL is not a valid PE file, the download fails with an explicit error.

The selected architecture is also validated against the embedded PE header. If --arch x86 is requested and the source returns an x64 DLL, the download fails instead of saving a mislabeled file.

The HTTP transport retries transient failures up to 5 times by default and rotates across a pool of 5 legitimate User-Agent strings unless you provide an explicit user_agent in configuration.

Retry policy settings:

• http_max_retries
• http_retry_backoff_seconds
• http_retry_jitter_seconds
• user_agent
• user_agent_pool

For pipeline integration, --json emits one structured JSON document and --sarif emits one SARIF v2.1.0 log. Both formats also serialize boundary errors such as invalid CLI input or unreadable DLL list files.

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Python Library

Basic Usage

from dll_downloader.api import (
    Architecture,
    DownloadDLLRequest,
)
from dll_downloader.runtime import (
    load_settings,
    create_dependencies,
)

settings = load_settings()
use_case, http_client, scanner = create_dependencies(settings)

try:
    response = use_case.execute(DownloadDLLRequest(
        dll_name="msvcp140.dll",
        architecture=Architecture.X64,
        scan_before_save=True,
        force_download=False,
        extract_archive=True,
    ))
    print(response)
finally:
    http_client.close()
    if scanner:
        scanner.close()

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Requirements

• Python 3.13 or 3.14
• See pyproject.toml for dependencies

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Contributing

Contributions are welcome. Please open a PR with clear changes and tests if needed.

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Support the Project

If you find DLL-Downloader useful, consider supporting its development:

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License

See the LICENSE file for details.

Attribution Required:

• Author: Marc Rivero Lopez
• Repository: github.com/seifreed/DLL-Downloader

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_{Built for secure, reliable DLL acquisition}