File System Filter Drivers and File Access Control

On occasion if you work in information security you see things like this pop up: https://bugs.chromium.org/p/project-zero/issues/detail?id=989

To me this is a very good teachable moment for people who might come to this forum seeking help on how to do something similar. Obviously Tavis explains why attempting to use a blacklist was bad and what can happen, but I’d love to hear from a knowledgeable dev here on why they might have been trying to do this as they did and what the correct way to implement this would have been?

This is a darn interesting post… and should probably be sent to NTFSD (where the file system devs hang out) and not NTDEV.

Peter
OSR
@OSRDrivers

In order to inspect encrypted data streams using SSL/TLS, Kasperky
installs a WFP driver to intercept all outgoing HTTPS connections.
They effectively proxy SSL connections, inserting their own
certificate as a trusted authority in the system store and then
replace all leaf certificates on-the-fly. This is why if you examine a
certificate when using Kaspersky Antivirus, the issuer appears to be
“Kaspersky Anti-Virus Personal Root”.

Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=978

Regardless if they should have used a filesystem ACL or if it is
pointless protect the file on some scenarios (physical access to the
system you use for surfing), or if they should check a lot of things
more in the minifilter, regardless if is worse the cure than the
disease… I think they did a non negligible amount of work!

2017-01-04 14:16 GMT+01:00 :

> This is a darn interesting post… and should probably be sent to NTFSD
> (where the file system devs hang out) and not NTDEV.
>
> Peter
> OSR
> @OSRDrivers
>
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