пример находит строку текста в памяти другого процесса, и меняет её на другую строку такой же длины (проверять в notepad++)

main.cpp

#include <windows.h>
#include <tlhelp32.h>
#include <iostream>
#include <vector>
#include <string>
#include <shellapi.h>

bool IsRunAsAdmin() {
    bool isAdmin = false;
    HANDLE token = NULL;
    if (OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &token)) {
        TOKEN_ELEVATION elevation;
        DWORD size = sizeof(elevation);
        if (GetTokenInformation(token, TokenElevation, &elevation, sizeof(elevation), &size)) {
            isAdmin = elevation.TokenIsElevated != 0;
        }
        CloseHandle(token);
    }
    return isAdmin;
}

void ElevatePrivileges() {
    wchar_t szPath[MAX_PATH];
    if (GetModuleFileNameW(NULL, szPath, MAX_PATH)) {
        SHELLEXECUTEINFOW sei = { sizeof(sei) };
        sei.cbSize = sizeof(sei);
        sei.lpVerb = L"runas";
        sei.lpFile = szPath;
        sei.hwnd = NULL;
        sei.nShow = SW_NORMAL;
        if (ShellExecuteExW(&sei)) {
            ExitProcess(0);
        }
    }
}

DWORD GetProcessIdByName(const wchar_t* processName) {
    DWORD pid = 0;
    HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    if (snapshot != INVALID_HANDLE_VALUE) {
        PROCESSENTRY32W processEntry;
        processEntry.dwSize = sizeof(processEntry);
        if (Process32FirstW(snapshot, &processEntry)) {
            do {
                if (wcscmp(processEntry.szExeFile, processName) == 0) {
                    pid = processEntry.th32ProcessID;
                    break;
                }
            } while (Process32NextW(snapshot, &processEntry));
        }
        CloseHandle(snapshot);
    }
    return pid;
}

int main() {
    if (!IsRunAsAdmin()) {
        ElevatePrivileges();
        return 0;
    }

    // Нацеливаемся на классический Win32 Notepad++
    const wchar_t* targetProcess = L"notepad++.exe";
    std::string targetStr, newStr;

    std::cout << "Enter string to find (e.g. hello): ";
    std::cin >> targetStr;
    std::cout << "Enter new string (must be same length, e.g. world): ";
    std::cin >> newStr;

    if (targetStr.length() != newStr.length()) {
        std::cout << "Strings must be of equal length for this simple example!" << std::endl;
        system("pause");
        return 1;
    }

    DWORD pid = GetProcessIdByName(targetProcess);
    if (pid == 0) {
        std::cout << "Process notepad++.exe not found. Please open Notepad++ first." << std::endl;
        system("pause");
        return 1;
    }

    HANDLE processHandle = OpenProcess(PROCESS_VM_READ | PROCESS_VM_WRITE | PROCESS_VM_OPERATION | PROCESS_QUERY_INFORMATION, FALSE, pid);
    if (!processHandle) {
        std::cout << "Failed to open process. Error code: " << GetLastError() << std::endl;
        system("pause");
        return 1;
    }

    SYSTEM_INFO sysInfo;
    GetSystemInfo(&sysInfo);

    char* address = static_cast<char*>(sysInfo.lpMinimumApplicationAddress);
    char* maxAddress = static_cast<char*>(sysInfo.lpMaximumApplicationAddress);
    size_t replacementsCount = 0;

    while (address < maxAddress) {
        MEMORY_BASIC_INFORMATION mbi;
        if (VirtualQueryEx(processHandle, address, &mbi, sizeof(mbi)) == sizeof(mbi)) {
            if (mbi.State == MEM_COMMIT && (mbi.Protect & PAGE_READWRITE) && !(mbi.Protect & PAGE_GUARD)) {
                std::vector<char> buffer(mbi.RegionSize);
                SIZE_T bytesRead;

                if (ReadProcessMemory(processHandle, mbi.BaseAddress, buffer.data(), mbi.RegionSize, &bytesRead)) {
                    for (size_t i = 0; i <= bytesRead - targetStr.length(); ++i) {
                        if (memcmp(&buffer[i], targetStr.c_str(), targetStr.length()) == 0) {
                            char* matchAddress = static_cast<char*>(mbi.BaseAddress) + i;
                            SIZE_T bytesWritten;
                            if (WriteProcessMemory(processHandle, matchAddress, newStr.c_str(), newStr.length(), &bytesWritten)) {
                                replacementsCount++;
                            }
                        }
                    }
                }
            }
            address += mbi.RegionSize;
        }
        else {
            address += sysInfo.dwPageSize;
        }
    }

    std::cout << "Scan finished. Total replacements made: " << replacementsCount << std::endl;
    CloseHandle(processHandle);
    system("pause");
    return 0;
}