[Full-disclosure] AlShow version 1.91 <= Insecure DLL Hijacking Vulnerability (mfc90enu.dll, mfc90loc.dll, dwmapi.dll)



1. OVERVIEW

The AlShow application,part of AlTools PC Utilities, 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

A free media player plays DVD, VOB, IFO, AVI and over 30 media
formats. Player also supports FLV files like Youtube video downloads
through its online codec center. The codec center helps to
automatically download missing codecs. For sharing favorite scenes
with friends and family this media player supports audio and video
capturing to create small audio and video clips. Taking movie screen
shots for still pictures is also supported. Clips can later be
imported into a video editor to quickly create video mashups and
montages.


3. VULNERABILITY DESCRIPTION

The AlShow application passes an insufficiently qualified path in
loading its external libraries - "mfc90enu.dll, mfc90loc.dll,
dwmapi.dll" when a user opens its associated file with extensions -
3gp, ask, asx, avi, bmk, dat, divx, flv, idx, m4a, mka, mp4, mpe, ogm,
smi, sub, vob, wmp, wmv, wvx .


4. VERSIONS AFFECTED

1.91 and probably lower versions


5. PROOF-OF-CONCEPT/EXPLOIT

http://core.yehg.net/lab/pr0js/advisories/dll_hijacking/altools/poc/movie/Al-Zip,See,Show_dll-hacking.mp4
http://core.yehg.net/lab/pr0js/advisories/dll_hijacking/altools/poc/altools_dll-hijacking.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

ESTsoft Corp.
http://www.estsoft.com/
http://www.altools.com


9. CREDIT

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


10. DISCLOSURE TIME-LINE

N/A: vulnerability discovered
09-11-2010: notified vendor
09-12-2010: vulnerability disclosed


11. REFERENCES

Original Advisory URL:
http://core.yehg.net/lab/pr0js/advisories/dll_hijacking/[alshow]_1.91_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 [09-12-2010]

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