Install hijacking refers to the malicious act of taking control of a computer or device during the installation process of a legitimate software or application. This is typically done by injecting unauthorized code or software into the installation process, allowing the hijacker to gain access to the system and potentially steal sensitive information or install harmful malware. Install hijacking can occur through various means, such as fake software updates, deceptive pop-up ads, or compromised download links. It is a serious security threat that can compromise the integrity and functionality of a device, making it important for users to be cautious and only download software from trusted sources.