시스템 crash 이것에 대해서 질문 드립니다.

asdf     pts/0        user-0ccei1b.cab Tue Jul 19 13:46 - 14:00  (00:13)    
reboot   system boot  2.4.20-31.9smp   Tue Jul 19 13:41          (00:23)    
reboot   system boot  2.4.20-31.9smp   Tue Jul 19 13:34          (00:04)    
reboot   system boot  2.4.20-31.9smp   Tue Jul 19 13:30          (00:03)    
asdf     pts/0        user-0ccei1b.cab Tue Jul 19 08:53 - crash  (04:36)    

서버가 죽어있어서 점심때 리부팅을 해주고 로그를 보고 있는중..
마지막 로그인 asdf ==> crash 가 눈에 띄더군요.

서버를 다시 켜고 이것저것 하고 있는데
다시 asdf가 로그인해 있는것을 확인하고

wall 로 누구냐고 메일로 누군지 알려달라고 메시지를 보내니 바로 로그아웃을 해버렸습니다.

asdf 디렉토리에 들어가 보니..
a.out expand_stack expand_stack.c kon uselib24
이런 파일들이 있네요..

어떻게 대처를 해야할지 모르겠네요.

xpand_stack SMP race local root exploit
*
* Copyright (C) 2005 Christophe Devine and Julien Tinnes
*
* This program is quite unreliable - you may have to run it
* several times before getting a rootshell. It was only tested
* so far on a bi-xeon running Debian testing / Linux 2.4.29-rc1.
*
* Vulnerability discovered by Paul Starzetz <ihaquer at isec.pl>
* http://www.isec.pl/vulnerabilities/isec-0022-pagefault.txt
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/