Microsoft Windows LoadUvsTable() Buffer Overflow

                							

                # Date: 15-03-2017
# Author: Hossein Lotfi (https://twitter.com/hosselot)
# CVE: CVE-2016-7274
 
1. Description
 
An integer overflow error within the "LoadUvsTable()" function of usp10.dll
can be exploited to cause a heap-based buffer overflow. Full analysis is
available at:
 
http://blogs.flexerasoftware.com/secunia-research/2016/12/microsoft_windows_loaduvstable_heap_based_buffer_overflow_vulnerability.html
 
 
2. Proof of Concept
 
open aC:\Windows\Fonts\phagspa.ttfa in a hex editor and change the value at
offset 0x2051 from 0x00000006 to 0x33333334.
 
 
3. Solution:
 
Microsoft initially tried to fixed the issue in MS16-147, but the fix was
incomplete and the issue remained unpatched til Microsoft March 2017 patch
release:
 
https://twitter.com/hosselot/status/809059287037251584
 
It appears MS17-013 finally fixed the vulnerability properly:
 
https://technet.microsoft.com/en-us/library/security/ms17-013.aspx
 
@hosselot

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