Author: Ye Yint Min Thu Htut

1. OVERVIEW

The Foxit Reader is vulnerable to Insecure DLL Hijacking
Vulnerability. Similar terms that describe this vulnerability
have been come up with Remote Binary Planting, and Insecure DLL
Loading/Injection/Hijacking/Preloading.

2. PRODUCT DESCRIPTION

Foxit Reader is a multilingual freemium PDF tool that can create, view,
edit, digitally sign, and print PDF files. Foxit Reader is developed by
Fremont, California-based Foxit Software Incorporated. Early versions of
Foxit Reader were notable for startup performance and small file size.

3. VULNERABILITY DESCRIPTION

The Foxit Reader application passes an insufficiently qualified path in
loading an external library when a user launch the application

Affected Library List
---------------------
[*] RICHED20.DLL
[*] CRYPTSP.dll
[*] USERENV.dll
[*] profapi.dll
[*] RpcRtRemote.dll
[*] apphelp.dll
[*] ntmarta.dll
[*] DEVRTL.dll
[*] credssp.dll
[*] DNSAPI.dll
[*] rasadhlp.dll
[*] schannel.DLL
[*] RASAPI32.dll
[*] rtutils.dll
[*] sensapi.dll
[*] dhcpcsvc.DLL
[*] secur32.dll
[*] ncrypt.dll
[*] bcrypt.dll
[*] GPAPI.dll
[*] cryptnet.dll
[*] dhcpcsvc6.DLL
[*] Cabinet.dll
[*] WindowsCodecs.dll

4. VERSIONS AFFECTED
8.3.1.21155 and prior

5. PROOF-OF-CONCEPT/EXPLOIT
http://blog.pentest.space/2018/04/foxit-reader-83121155-unsafe-dll.html
Tested Platform: Windows 7 x64 (Fresh Windows)

6. IMPACT
This occurs when an application fails to resolve a DLL because the DLL does
not exist in the specified path or search directories. If this happens, a
malicious Dll with the same name can be placed in the specified path
directory leading to remote code execution.

7. SOLUTION
Update the latest version of Foxit PDF reader
https://www.foxitsoftware.com/support/security-bulletins.php

For both groups:
    Microsoft has a great article explaining the DLL-related registry keys
and how they can be used to protect applications -

http://blogs.technet.com/b/srd/archive/2010/08/23/more-information-about-dll-preloading-remote-attack-vector.aspx

8. VENDOR
Foxit
https://www.foxitsoftware.com/pdf-reader/

9. CREDIT
This vulnerability was discovered by Ye Yint Min Thu htut,
http://pentest.space

10. DISCLOSURE TIME-LINE
07-30-2017: vulnerability discovered
07-30-2017: notified vendor
04-18-2018: vendor fixed and patch released (
https://www.foxitsoftware.com/support/security-bulletins.php)
04-20-2018: vulnerability disclosed

11. REFERENCES
https://support.microsoft.com/en-us/help/2389418/secure-loading-of-libraries-to-prevent-dll-preloading-attacks
https://cwe.mitre.org/data/definitions/427.html