Apple provides legitimate ways to download the Mountain Lion installer and the subsequent 10.8.3 update for free.
You can download the full Mac OS X Mountain Lion Installer directly from Apple Support . This file is approximately 4.45 GB and allows you to install the base 10.8 operating system. Mac OSX Mountain Lion 10.8.3 Free Download
Downloading and Installing OS X Mountain Lion 10.8.3 OS X Mountain Lion (version 10.8) was a major release of macOS that brought many iOS-inspired features to the Mac. While it has since been succeeded by many newer versions, it remains a critical operating system for users with older Mac hardware that cannot support modern software. Apple provides legitimate ways to download the Mountain
The specifically introduced key improvements, including support for Windows 8 in Boot Camp and the ability to redeem iTunes gift cards using the Mac's built-in camera. How to Get OS X Mountain Lion 10.8.3 Downloading and Installing OS X Mountain Lion 10
Before downloading, ensure your Mac meets these hardware and software specifications: Mac OS X Mountain Lion Installer - Apple Support
If your system is already running an earlier version of Mountain Lion (10.8, 10.8.1, or 10.8.2), you should download the OS X Mountain Lion Update v10.8.3 (Combo) . The "Combo" update is recommended because it can update any previous version of 10.8 to 10.8.3 in one step. System Requirements