1. OVERVIEW

The Nuance PDF Reader application 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

The free Nuance PDF Reader is an alternative to Adobe Reader that is
smaller, more secure, and for the first time connects desktop PDF with
cloud-based PDF-to-Microsoft Office conversion services. The Nuance
PDF Reader also enables PDF form save, annotations and Microsoft
SharePoint features not available in alternatives.


3. VULNERABILITY DESCRIPTION

The Nuance PDF Reader application passes an insufficiently qualified
path in loading its external libraries -
"dwmapi.dll, exceptiondumpdll.dll" when a user opens its associated
file with extension - pdf .


4. VERSIONS AFFECTED

6.0 and probably lower versions


5. PROOF-OF-CONCEPT/EXPLOIT

http://core.yehg.net/lab/pr0js/advisories/dll_hijacking/nuance_pdf_reader/poc/movie/nuance_pdf_reader-6.0_dll-hijacking.mp4
http://core.yehg.net/lab/pr0js/advisories/dll_hijacking/nuance_pdf_reader/poc/nuance_pdf_reader-6.0_dll-hijacking-poc.zip

Tested Platform: Windows XP Service Pack 3 (Fresh Windows)


6. IMPACT

Attackers can trigger a successful exploit against a victim user in a
number of ways such as placing a malicious external
library file made as hidden attribute and a seemingly interesting file
in network shares, usb drives, file sharing networks,
social networks, ..etc  


7. SOLUTION

Fixed version from the vendor has not been released yet.
However, it is suggested that the following workarounds be deployed by
users to protect increasing mass exploitation of this
vulnerability class:
- Disable loading of libraries from WebDAV and remote network shares
- Disable the WebClient service
Please see workaround solution links in References section.


8. VENDOR

Nuance Communications
http://www.nuance.com/


9. CREDIT

This vulnerability was discovered by Aung Khant, http://yehg.net, YGN
Ethical Hacker Group, Myanmar.


10. DISCLOSURE TIME-LINE

09-07-2010: notified vendor
09-13-2010: vulnerability disclosed


11. REFERENCES

Original Advisory URL:
http://core.yehg.net/lab/pr0js/advisories/dll_hijacking/[nuance_pdf_reader]_6.0_insecure_dll_hijacking
Workaround Solution: http://support.microsoft.com/kb/2264107
Workaround Solution:
https://www.microsoft.com/technet/security/advisory/2269637.mspx#EGF
Developer Solution:
http://msdn.microsoft.com/en-us/library/ff919712%28v=VS.85%29.aspx
Unofficial DLL Hijacking List:
http://www.corelan.be:8800/index.php/2010/08/25/dll-hijacking-kb-2269637-the-unofficial-list/
Testing for DLL Hijacking:
http://core.yehg.net/lab/pr0js/view.php/when_testing_for_dll_hijacking.txt

#yehg [09-13-2010]