Roblox Offset Dumper & Pattern Scanning Guide

The Problem: Roblox's Ever-Changing Memory

Every time Roblox updates, developers who create external tools or analyze the game client face a significant challenge: memory addresses for functions and data structures change. An address that pointed to the player's health one day might point to something completely different or nothing at all the next. This makes tools that rely on static, hard-coded addresses incredibly fragile. They break with every single update.

The Solution: Dynamic Pattern Scanning

To solve this, we use a technique called pattern scanning (or signature scanning). Instead of searching for a specific address, we search for a unique sequence of bytes a "pattern" or "signature" that is associated with the data or function we want to find. Since this sequence of bytes is part of the game's actual machine code, it's far less likely to change between updates than the memory address where it's located.

An Offset Dumper is a tool that automates this process. It scans the running Roblox process for a list of predefined patterns and "dumps" the current memory addresses (offsets) it finds, allowing tools to work reliably across updates.

Core Concepts Explained

Proof-of-Concept: C++ Scanner

Here is a complete, commented proof-of-concept C++ application that demonstrates how to build a basic pattern scanner. This code finds the Roblox process, scans its memory for a specific signature, and correctly calculates the final address, even when dealing with RIP-relative instructions.

// main.cpp
#include <iostream>
#include <vector>
#include <string>
#include <windows.h>
#include <tlhelp32.h>
#include <iomanip>

// A structure to hold our signature details
struct Signature {
    std::string name;
    std::string pattern;
    int ripOffset;
    int instructionLength; // Total length of the instruction for RIP calculation
};

// Converts a string pattern like "48 8D 05 ? ? ? ?" to bytes and a mask.
bool PatternToBytes(const std::string& pattern, std::vector<BYTE>& outBytes, std::string& outMask) {
    outBytes.clear();
    outMask.clear();
    size_t i = 0;
    while (i < pattern.length()) {
        if (pattern[i] == ' ') { i++; continue; }
        if (pattern[i] == '?') {
            outBytes.push_back(0x00);
            outMask += '?';
            i += (i + 1 < pattern.length() && pattern[i + 1] == '?') ? 2 : 1;
        } else {
            if (i + 1 >= pattern.length()) return false;
            char hexChars[3] = { pattern[i], pattern[i + 1], '\0' };
            outBytes.push_back(static_cast<BYTE>(strtoul(hexChars, nullptr, 16)));
            outMask += 'x';
            i += 2;
        }
    }
    return !outBytes.empty();
}

// Scans a memory buffer for a given pattern and mask.
uintptr_t ScanBuffer(const BYTE* buffer, SIZE_T bufferSize, const std::vector<BYTE>& pattern, const std::string& mask) {
    const size_t patternLen = pattern.size();
    if (patternLen == 0 || patternLen > bufferSize) return 0;
    for (size_t i = 0; i <= bufferSize - patternLen; ++i) {
        bool match = true;
        for (size_t j = 0; j < patternLen; ++j) {
            if (mask[j] == 'x' && pattern[j] != buffer[i + j]) {
                match = false;
                break;
            }
        }
        if (match) return i;
    }
    return 0;
}

// Gets the Process ID (PID) for a given process name.
DWORD GetProcessIdByName(const std::wstring& processName) {
    HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    if (snapshot == INVALID_HANDLE_VALUE) return 0;
    PROCESSENTRY32W processEntry = { sizeof(PROCESSENTRY32W) };
    if (Process32FirstW(snapshot, &processEntry)) {
        do {
            if (_wcsicmp(processEntry.szExeFile, processName.c_str()) == 0) {
                CloseHandle(snapshot);
                return processEntry.th32ProcessID;
            }
        } while (Process32NextW(snapshot, &processEntry));
    }
    CloseHandle(snapshot);
    return 0;
}

int main() {
    const std::wstring targetProcessName = L"RobloxPlayerBeta.exe";
    Signature sigToFind = {
        "ExampleRipAddress",
        "48 8D 0D ? ? ? ? E8 ? ? ? ? 48 8B 05",
        3, // The '?' (displacement) starts at the 3rd byte (0-indexed).
        7  // The instruction containing the displacement is 7 bytes long.
    };

    // 1. Find the Roblox process
    DWORD pid = GetProcessIdByName(targetProcessName);
    if (pid == 0) {
        std::wcerr << L"Roblox process not found. Is the game running?" << std::endl;
        system("pause");
        return 1;
    }
    std::wcout << L"Found Roblox process with PID: " << pid << std::endl;

    // 2. Open the process to read its memory
    HANDLE hProcess = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, pid);
    if (hProcess == NULL) {
        std::wcerr << L"Failed to open process. Error: " << GetLastError() << std::endl;
        system("pause");
        return 1;
    }

    // 3. Get main module info to calculate the final offset
    uintptr_t moduleBaseAddress = 0;
    HANDLE hModuleSnap = CreateToolhelp32Snapshot(TH32CS_SNAPMODULE | TH32CS_SNAPMODULE32, pid);
    if (hModuleSnap != INVALID_HANDLE_VALUE) {
        MODULEENTRY32W moduleEntry = { sizeof(moduleEntry) };
        moduleEntry.dwSize = sizeof(moduleEntry);
        if (Module32FirstW(hModuleSnap, &moduleEntry)) {
            if (_wcsicmp(moduleEntry.szModule, targetProcessName.c_str()) == 0) {
                moduleBaseAddress = (uintptr_t)moduleEntry.modBaseAddr;
            }
        }
        CloseHandle(hModuleSnap);
    }
    if (moduleBaseAddress == 0) {
        std::wcerr << L"Could not find module base address." << std::endl;
        CloseHandle(hProcess);
        system("pause");
        return 1;
    }
    std::wcout << L"Module base: 0x" << std::hex << moduleBaseAddress << std::dec << L"\n";

    // 4. Iterate over the process's memory regions
    uintptr_t foundAddress = 0;
    uintptr_t currentAddress = 0;
    MEMORY_BASIC_INFORMATION mbi;
    std::vector<BYTE> patternBytes;
    std::string mask;
    PatternToBytes(sigToFind.pattern, patternBytes, mask);

    while (VirtualQueryEx(hProcess, (LPCVOID)currentAddress, &mbi, sizeof(mbi))) {
        if (mbi.State == MEM_COMMIT && (mbi.Protect & (PAGE_READONLY | PAGE_READWRITE | PAGE_EXECUTE_READ | PAGE_EXECUTE_READWRITE))) {
            std::vector<BYTE> buffer(mbi.RegionSize);
            SIZE_T bytesRead;
            if (ReadProcessMemory(hProcess, mbi.BaseAddress, buffer.data(), mbi.RegionSize, &bytesRead)) {
                uintptr_t localOffset = ScanBuffer(buffer.data(), bytesRead, patternBytes, mask);
                if (localOffset != 0) {
                    uintptr_t patternAddress = (uintptr_t)mbi.BaseAddress + localOffset;
                    if (sigToFind.ripOffset != -1) {
                        int32_t displacement = 0;
                        memcpy(&displacement, &buffer[localOffset + sigToFind.ripOffset], sizeof(displacement));
                        foundAddress = patternAddress + sigToFind.instructionLength + displacement;
                    } else {
                        foundAddress = patternAddress;
                    }
                    break;
                }
            }
        }
        currentAddress = (uintptr_t)mbi.BaseAddress + mbi.RegionSize;
    }

    // 5. Print the result
    if (foundAddress != 0) {
        uintptr_t offset = foundAddress - moduleBaseAddress;
        std::wcout << L"\nSuccess!" << std::endl;
        std::wcout << L"Found '" << std::wstring(sigToFind.name.begin(), sigToFind.name.end()) << L"' at address: 0x" << std::hex << std::uppercase << foundAddress << std::endl;
        std::wcout << L"Offset from module base: 0x" << std::hex << std::uppercase << offset << std::endl;
    } else {
        std::wcerr << L"\nCould not find signature for '" << std::wstring(sigToFind.name.begin(), sigToFind.name.end()) << L"'." << std::endl;
    }

    CloseHandle(hProcess);
    system("pause");
    return 0;
}