Monday, June 5, 2017

Exploring Virtual Address Descriptors under Windows 10

This blog post is about my personal attempt to superficially list VAD types under Windows 10. It all started when I was wondering, out of sheer curiosity, if there's any way to determine the VAD type (MMVAD_SHORT or MMVAD) other than by looking at the pool tag preceding the structure. In order to do that, I had to list all VAD types, do some reverse engineering, and then draw a table describing what I've been able to find.
You can view the full document by clicking here 



From the table above it is possible to deduce the VAD structure type from both the VadType and PrivateMemory flags.

VadType flag
PrivateMemory flag
Type
0
0
MMVAD
0
1
MMVAD_SHORT
1
1
MMVAD
2
0
MMVAD
3
1
MMVAD_ENCLAVE

To test it out, I wrote a kernel driver that prints the deduced VAD type for each node of calc.exe. It also prints the pool tag so we can check the result.


And that's all for this article.
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