User Account Control (UAC)

User Account Control (UAC) enhances Windows security by preventing malware from running with admin rights.

The basics of how UAC works

UAC asks for user permission when an app needs admin access. Child processes inherit this access from their parent process, as long as both have the same integrity level.

Windows uses integrity levels to protect processes:

• High-integrity: Trusted apps that modify system data (for example, disk partition tools)
  
• Low-integrity: Less trusted apps that might risk the system (for example, web browsers)
  

Apps with lower integrity levels can’t change data in apps with higher levels. When a standard user runs an app needing admin access, UAC asks for valid admin credentials.

See this article from Microsoft for more information about how UAC works, and how to change it.