Friday, April 04, 2008

Disable or Enable NX bit in Vista via commandline

Data Execution Prevention (DEP) and the NX bit (No eXecute) CPU flag on AMD processors and XD eXecute Disable on Intel processors can be of great help in buffer overflow mitigation. Of course, it can also hinder other applications.

You can disable it in Vista by starting an Administrative cmd (right click cmd - Run As Administrator) and typing:

bcdedit /set nx alwaysoff
bcdedit /set {current} nx alwaysoff
BCDEdit can be used to enable or disable DEP, PAE and more.

You can also set DEP by right clicking My Computer - Properties - System Properties - Advanced System Settings - Performance - Data Execution Prevention.

Some applications don't work well unless they are selected as DEP exceptions (like Battle.NET via PVPGN or Hitachi HiTrack's JVM).