EATGuard

Implementation of an export address table protection mitigation, like Export Address Filtering (EAF)

How It Works

This project is composed of three binaries that, when compiled, can be found in EATGuard\bin\. They are:

1. EATGuardApplication.exe - "Malicious" application that loads EATGuardDll.dll into the process and then executes some executable code (shellcode) which executes notepad.exe.
2. EATGuardDll.dll - DLL that provides a "bridge" between user-mode and kernel-mode. This DLL registers a Vectored Exception Handler (VEH) which sends detections of access to the kernel32.dll Export Address Table (EAT) to the EATGuardDriver.sys driver. This DLL allocates a guard page on the kernel32.dll EAT which causes an exception when the EAT is accessed within the EATGuardApplication.exe process space. This routes execution to the registered VEH which processes these exceptions and is responsible for continuing execution after analysis is completed.
3. EATGuardDriver.sys - Kernel-mode device driver which verifies access to the kernel32.dll EAT. Currently, as a POC, it checks if the memory which accesses kernel32.dll is backed by disk.

How To Use

Please note that EATGuardApplication.exe loads EATGuardDll.dll from the relative path of EATGuardApplication.exe. This means both the .exe and .dll need to be in the same directory when executing. Please note also do not run this project on a machine that has kernel debugging enabled. This can cause issues, as the EATGuardDll.dll uses a single-step exception for continuation of execution. Here is an example usage of the project:

C:\Users\ANON\Desktop>sc create EATGUARD type= kernel binPath= C:\Users\ANON\Desktop\EATGuardDriver.sys
[SC] CreateService SUCCESS

C:\Users\ANON\Desktop>sc start EATGUARD

SERVICE_NAME: EATGUARD
        TYPE               : 1  KERNEL_DRIVER
        STATE              : 4  RUNNING
                                (STOPPABLE, NOT_PAUSABLE, IGNORES_SHUTDOWN)
        WIN32_EXIT_CODE    : 0  (0x0)
        SERVICE_EXIT_CODE  : 0  (0x0)
        CHECKPOINT         : 0x0
        WAIT_HINT          : 0x0
        PID                : 0
        FLAGS              :

C:\Users\ANON\Desktop>EATGuardApplication.exe
[+] KERNEL32.dll EAT: 0x00007FFB1D83F898
[+] Number of functions in the KERNEL32.dll EAT: 1678
[+] EATGuard analysis complete!
    [+] Target address: 0x24AA138005C
        [>] IsRipRwxMemory: TRUE
        [>] IsRipMappedSection: FALSE
        [>] IsRipBackedByImage: FALSE
        [>] HasPageProtectionChanged: FALSE
        [>] RegionBaseAddress: 0x24AA1380000
        [>] MemoryRegionSize: 0x1000
        [>] MemoryCommtSize: 0x1000
[+] EATGuard analysis complete!
    [+] Target address: 0x24AA138005F
        [>] IsRipRwxMemory: TRUE
        [>] IsRipMappedSection: FALSE
        [>] IsRipBackedByImage: FALSE
        [>] HasPageProtectionChanged: FALSE
        [>] RegionBaseAddress: 0x24AA1380000
        [>] MemoryRegionSize: 0x1000
        [>] MemoryCommtSize: 0x1000
[+] EATGuard analysis complete!
    [+] Target address: 0x24AA138008F
        [>] IsRipRwxMemory: TRUE
        [>] IsRipMappedSection: FALSE
        [>] IsRipBackedByImage: FALSE
        [>] HasPageProtectionChanged: FALSE
        [>] RegionBaseAddress: 0x24AA1380000
        [>] MemoryRegionSize: 0x1000
        [>] MemoryCommtSize: 0x1000
[+] EATGuard analysis complete!
    [+] Target address: 0x24AA138009B
        [>] IsRipRwxMemory: TRUE
        [>] IsRipMappedSection: FALSE
        [>] IsRipBackedByImage: FALSE
        [>] HasPageProtectionChanged: FALSE
        [>] RegionBaseAddress: 0x24AA1380000
        [>] MemoryRegionSize: 0x1000
        [>] MemoryCommtSize: 0x1000
[+] EATGuard analysis complete!
    [+] Target address: 0x24AA13800A2
        [>] IsRipRwxMemory: TRUE
        [>] IsRipMappedSection: FALSE
        [>] IsRipBackedByImage: FALSE
        [>] HasPageProtectionChanged: FALSE
        [>] RegionBaseAddress: 0x24AA1380000
        [>] MemoryRegionSize: 0x1000
        [>] MemoryCommtSize: 0x1000

(...)TRUNCATED(...)

This project is a POC which mimics the functionality of Export Address Filtering.