Grzegorz Tworek  

572 Followers
234 Following
20 Posts
By-design AV bypass with "dev drive" ๐Ÿ˜…
I really like this feature!
Update your detection rules if you want to spot this...
And what fsutil devdrv actually does? Here you have it:
1. devdrv enable -> FsEnableDevDrive=1 in CCS\Control\FileSystem
2. disallowAv -> FltmgrDevDriveAllowAntivirusFilter=0 in CCS\Control\FilterManager
3. clearFiltersAllowed -> FsFlags + FsGuid in CCS\Control\FileSystemVolumes\{VOLUME_GUID}
4. trust -> DeviceIoControl(FSCTL_SET_PERSISTENT_VOLUME_STATE, PERSISTENT_VOLUME_STATE_TRUSTED_VOLUME)
And you can enjoy the bypass without even touching fsutil.exe ๐Ÿ˜Ž
Short video showing you how to play with application-based conditional ACLs on your own: https://youtu.be/4Lm0UWWa1gY
How to use conditional ACEs to get a file one app can open, while another one cannot.

YouTube
Conditional ACLs, making the same file allowed for one app, denied for another one... ๐Ÿ˜ฎ
I guess I know where I will dig during next weeks... ๐Ÿ˜Ž
๐Ÿค”
After some "over lunch reversing" magic by
@x86matthew, I have modified his code a bit, and I am ready to send a byte or two with DeviceIoControl().
If for any reason you want to see my version, it's here: https://github.com/gtworek/PSBits/blob/master/Misc/HttpCommunicationOpenHandle.c
PSBits/HttpCommunicationOpenHandle.c at master ยท gtworek/PSBits

Simple (relatively) things allowing you to dig a bit deeper than usual. - PSBits/HttpCommunicationOpenHandle.c at master ยท gtworek/PSBits

GitHub
Do you know any piece of code successfully opening \Device\Http\Communication device?
Is "UlOpenPacket000" EA necessary? Something else? I didn't succeed so far, and couple of IOCTLs still waits on my list ;)
New release of VolatileDataCollector has arrived. A LOT more details about DLLs loaded (thank you daem0nc0re for inspiration!), no other changes.
64bit DLLs for now, but WOW support is coming soon :)
Enjoy: https://github.com/gtworek/VolatileDataCollector

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