fsfilter-rs

A rust library to monitor filesystem and more in windows.

MINIFILTER

See MINIFILTER.md for building the minifilter or just right click install using the .inf file provided in releases.

You can also build using EWDK if you don't want to install Visual Studio, SDK and WDK.

NOTE: By default, it is built for Windows 10 and above.

NOTE: Enable Loading of Test Signed Drivers by executing Bcdedit.exe -set TESTSIGNING ON in administrative cmd.

RUNNING EXAMPLE

Use cargo run --bin minifilter --release to run the example application or just run the .exe provided in releases as administrator( for some reason the new default terminal (not the one that opens when you run it as administrator) on 2H22 is very, very slow).

The program starts to print the IOMessage which is defined like:

#[repr(C)]
pub struct IOMessage {
    /// The file extension
    pub extension: [wchar_t; 12],
    /// Hard Disk Volume Serial Number where the file is saved (from [`FILE_ID_INFO`])
    pub file_id_vsn: c_ulonglong,
    /// File ID on the disk ([`FILE_ID_INFO`])
    pub file_id_id: [u8; 16],
    /// Number of bytes transferred (`IO_STATUS_BLOCK.Information`)
    pub mem_sized_used: c_ulonglong,
    /// (Optional) File Entropy calculated by the driver
    pub entropy: f64,
    /// Pid responsible for this io activity
    pub pid: c_ulong,
    /// Windows IRP Type caught by the minifilter:
    /// - NONE (0)
    /// - READ (1)
    /// - WRITE (2)
    /// - SETINFO (3)
    /// - CREATE (4)
    /// - CLEANUP (5)
    pub irp_op: c_uchar,
    /// Is the entropy calculated?
    pub is_entropy_calc: u8,
    /// Type of i/o operation:
    /// - FILE_CHANGE_NOT_SET (0)
    /// - FILE_OPEN_DIRECTORY (1)
    /// - FILE_CHANGE_WRITE (2)
    /// - FILE_CHANGE_NEW_FILE (3)
    /// - FILE_CHANGE_RENAME_FILE (4)
    /// - FILE_CHANGE_EXTENSION_CHANGED (5)
    /// - FILE_CHANGE_DELETE_FILE (6)
    /// - FILE_CHANGE_DELETE_NEW_FILE (7)
    /// - FILE_CHANGE_OVERWRITE_FILE (8)
    pub file_change: c_uchar,
    /// The driver has the ability to monitor specific directories only (feature currently not used):
    /// - FILE_NOT_PROTECTED (0): Monitored dirs do not contained this file
    /// - FILE_PROTECTED (1)
    /// - FILE_MOVED_IN (2)
    /// - FILE_MOVED_OUT (3)
    pub file_location_info: c_uchar,
    /// File path on the disk
    pub filepathstr: String,
    /// Group Identifier (maintained by the minifilter) of the operation
    pub gid: c_ulonglong,
    /// see class [`RuntimeFeatures`]
    pub runtime_features: RuntimeFeatures,
    /// Size of the file. Can be equal to -1 if the file path is not found.
    pub file_size: i64,
    /// Rough time at which the IRP was created
    pub time: SystemTime,
}

We end the process using ctrl + c in the example video:

PERFORMANCE

The performance of the minifilter doesn't really exceed <1% of the CPU usage (I never saw it tickle even to 1% while running scripts to make multiple temporary files). Although depending on you console if you try running cargo run --bin minifilter --release you might see spikes reaching 1-3% but that is because of the console itself( comment out the writeln! in the bin example) or try changing consoles (maybe run minifilter.exe directly).

DEBUGGING

See DEBUG for setting up VMware windows machine debugging with VirtualKD-Redux and WinDbg.

MAINTAINERS

Feel free to open issues to ask any questions/queries. You're free to ping the current maintainers.

Currently maintained by the following:

• sn99 (original author)

Previous maintainers:

• N/A

LICENSE

This project is licensed under the terms of the MIT license.

ACKNOWLEDGEMENTS

• RansomWatch
• SitinCloud
• SubconsciousCompute