反调试 - 调试对象

原理

当一个程序被调试时，有两种情况：“打开” 和 “附加” ，分别调用 CreateProcess 和 DebugActiveProcess 创建一个调试对象，而通过检测系统中有无调试对象，可以判断出是否有进程正在被调试。这种方法适用于全局反调试，也就是说即使被调试的程序不是自身，也仍然会被检测到。

代码示例

// Test_Console_1.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <Windows.h>
#include <intrin.h>

using namespace std;

typedef struct _UNICODE_STRING {
    
    
    USHORT Length;
    USHORT MaximumLength;
    PWSTR  Buffer;
} UNICODE_STRING, * PUNICODE_STRING;
typedef struct _OBJECT_TYPE_INFORMATION {
    
    
    UNICODE_STRING TypeName;
    ULONG TotalNumberOfHandles;
    ULONG TotalNumberOfObjects;
}OBJECT_TYPE_INFORMATION, * POBJECT_TYPE_INFORMATION;
typedef struct _OBJECT_ALL_INFORMATION {
    
    
    ULONG NumberOfObjects;
    OBJECT_TYPE_INFORMATION ObjectTypeInformation[1];
}OBJECT_ALL_INFORMATION, * POBJECT_ALL_INFORMATION;
typedef enum _OBJECT_INFORMATION_CLASS {
    
    
    ObjectBasicInformation,
    ObjectNameInformation,
    ObjectTypeInformation,
    ObjectAllInformation,
    ObjectDataInformation
} OBJECT_INFORMATION_CLASS;
typedef NTSTATUS(WINAPI* pNtQueryObject)(
    HANDLE  Handle,
    OBJECT_INFORMATION_CLASS ObjectInformationClass,
    PVOID ObjectInformation,
    ULONG ObjectInformationLength,
    PULONG ReturnLength
    );

int main()
{
    
    
    // 初始化
    ULONG objSize = 0;
    PVOID p_Memory = NULL;
    POBJECT_ALL_INFORMATION p_ObjectAllInfo = NULL;
    PUCHAR p_ObjInfoLocation = NULL;
    POBJECT_TYPE_INFORMATION p_ObjectTypeInfo = NULL;

    // 获取 NtQueryObject 地址
    pNtQueryObject NtQueryObject = (pNtQueryObject)GetProcAddress(LoadLibrary(L"ntdll.dll"),"ZwQueryObject");
    if (NtQueryObject == NULL) {
    
    
        goto main_end;
    }

    // 获取调试对象信息大小（返回 C0000004：STATUS_INFO_LENGTH_MISMATCH：信息长度不匹配）
    NtQueryObject(NULL, ObjectAllInformation, &objSize, sizeof(ULONG),&objSize);

    // 分配内存
    p_Memory = VirtualAlloc(NULL, objSize, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
    if (p_Memory == NULL) {
    
    
        goto main_end;
    }
    
    // 遍历对象信息
    if (NtQueryObject(NULL, ObjectAllInformation, p_Memory, objSize, NULL) != 0) {
    
    
        goto main_end;
    }
    p_ObjectAllInfo = (POBJECT_ALL_INFORMATION)p_Memory;
    p_ObjInfoLocation = (PUCHAR)p_ObjectAllInfo->ObjectTypeInformation;
    for (UINT i = 0; i < p_ObjectAllInfo->NumberOfObjects; i++) {
    
    
        p_ObjectTypeInfo = (POBJECT_TYPE_INFORMATION)p_ObjInfoLocation;
        if (wcscmp(L"DebugObject", p_ObjectTypeInfo->TypeName.Buffer) == 0) {
    
    
            if (p_ObjectTypeInfo->TotalNumberOfObjects > 0) {
    
    
                cout << "发现调试器！" << endl;
                break;
            }
            else {
    
    
                cout << "没有调试器" << endl;
                break;
            }
        }
        p_ObjInfoLocation = (PUCHAR)p_ObjectTypeInfo->TypeName.Buffer;
        p_ObjInfoLocation += p_ObjectTypeInfo->TypeName.MaximumLength;
        ULONG_PTR tmp = ((ULONG_PTR)p_ObjInfoLocation) & -(int)sizeof(void*);
        if ((ULONG_PTR)tmp != (ULONG_PTR)p_ObjInfoLocation) {
    
    
            tmp += sizeof(void*);
        }
        p_ObjInfoLocation = ((unsigned char*)tmp);
    }

main_end:
    if(p_Memory){
    
    
        VirtualFree(p_Memory, 0, MEM_RELEASE);
    }
    getchar();
    return 0;
}

效果图

vs调试：

正常启动：

x64dbg 调试 calc.exe: