The last part of Google Summer of Code 2011 was used to implement
a Windows Kernel Driver responsible for hiding files and folders.
This new component will be used to conceal Cuckoo Box components,
present in the environment analysis. With this measure it’s possible to
avoid that some malware detect CuckooBox through some environment check,
looking for specific files or folders.
The Driver was implemented as a Filter Driver to maintain it independent
of the Windows version used in the environment, not using any kind
of hooking which may cause problems when using different versions of
Windows. The Filter Driver act on the file system IRP requisitions,
checking if a process marked for monitoring is doing requests that
involve opening an handle or searching for any file or folder that must
be filtered.
If so, the response is changed, informing the process that the file or
folder doesn’t exist. The IRP requisitions filtered are, IRP_MJ_CREATE,
IRP_MJ_QUERY_INFORMATION and IRP_MJ_DIRECTORY_CONTROL, which are the
most commonly used to search for files and opening handles.
Processes and files inspected by the Filter Driver are passed by an
user land program, using the communication port created by the Filter
Driver. Messages accepted are only FileAdd and ProcAdd, which inform
that a new file or folder must be filtered or an new process must be
monitored.
