Hooking Any Function

Description about hooking options in HyperDbg

Hooking is a powerful feature of HyperDbg. You can hook all user-mode and kernel-mode functions and expect a fast in-line hook or unlimited EPT hooks.

Currently, hooking functions is possible through the !epthook and !epthook2.

!epthook2 is generally a faster hook; however, it has some limitations that are mentioned here.

Assume that ExAllocatePoolWithTag is located at fffff805`5cdb2030.

As you can see on MSDN, this function is defined like this :

PVOID ExAllocatePoolWithTag(
  __drv_strictTypeMatch(__drv_typeExpr)POOL_TYPE PoolType,
  SIZE_T                                         NumberOfBytes,
  ULONG                                          Tag
);

Another thing is that the above function is called with Fastcall calling convention, and the parameters are passed in the following order rcx, rdx, r8, r9, and the rest of them are located on the stack. So, we have two options here to create a log from the parameters of this function. For example, we want to create a log from the Tags which is on r8.

HyperDbg> !epthook fffff805`5cdb2030 script { print(@r8); }

If we want to use !epthook2, then the following command is used :

HyperDbg> !epthook2 fffff805`5cdb2030 script { print(@r8); }