[C/ASM] Easy to use DLL hijacking examples

[zeffy]

Thank you for sharing your code atom0s! I've used something very similar to it before I created these template projects. The reason I opted to use complete ASM instead of inline is because it isn't supported by VC in x64 builds, only x86.

Additionally, calling your InitializeProxy (and thus LoadLibrary) from DllMain can cause the process to deadlock under certain conditions. For this reason, MSDN specifically advises people not to call LoadLibrary from DllMain. Although I've never encountered it happen in practice, that could change in the future or in edge cases. That's why I opted to delay the loading until one of its functions is actually called. Either approach works though.

[atom0s]

Originally Posted by zeffy

Thank you for sharing your code atom0s! I've used something very similar to it before I created these template projects. The reason I opted to use complete ASM instead of inline is because it isn't supported by VC in x64 builds, only x86.

Additionally, calling your InitializeProxy (and thus LoadLibrary) from DllMain can cause the process to deadlock under certain conditions. For this reason, MSDN specifically advises people not to call LoadLibrary from DllMain. Although I've never encountered it happen in practice, that could change in the future or in edge cases. That's why I opted to delay the loading until one of its functions is actually called. Either approach works though.

I generally do the same with late loading, generally via exporting an 'Install' function from the main hook and using a loader to invoke it. The example above was just a quick throw together to show off the macro method of making a fast proxy.

[zeffy]

Originally Posted by atom0s

I generally do the same with late loading, generally via exporting an 'Install' function from the main hook and using a loader to invoke it. The example above was just a quick throw together to show off the macro method of making a fast proxy.

That's a neat idea about exporting an 'Install' function!

I've actually been working on simplifying my project using macros similar to how you did (except in the assembly), which has made it much easier to maintain compared to before. I also fixed the "random" crashing bug that I referred to earlier (which was caused by stack corruption and some of the volatile registers getting mutilated by my proc resolver function ). If you or anyone else is interested in taking a look, here's an example of the changes I've made:
https://github.com/zeffy/proxydll_te...inmm/winmm.asm

Edit: OK I really fixed the register mutilation now... I was restoring r8 to r9 and r9 to r8 in the last commit.