Hardware Breakpoints: VirtualBox vs VMware

Debugging code which doesn’t want to be debugged (think software protection, anti-debugging tricks etc.) can be a headache.  Some plugins do exist for OllyDbg (Phantom, StrongOD to name but a few) which can help relieve the pain, but most of them require WinXP in order to work, due to employing the kind of tricks root kits use in order to hide the presence of the debugger from the debuggee.  Now unless you have a spare box lying around, the most convenient way to run XP is using virtualisation.

The first virtualisation software I ever used was VirtualBox and this served me well for everything I wanted to do.  I could debug without problem.  However, after upgrading my computer (E6300 -> 2500K), hardware breakpoints stopped working under VirtualBox.  At first I thought it was some new anti-debugging trick, but after trying and failing to use a hardware breakpoint in a completely unprotected program, I decided to try a different peice of virtualisation software.

After installing VMware, hardware breakpoints were firing perfectly once more.  So it seems VirtualBox doesn’t necessarily support hardware breakpoints, depending on your hardware.

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