Re: [ Hackerslab bug_paper ] Linux dump buffer overflow

[eugeneteo () EUGENETEO NET (Eugene Teo)]

server running Redhat 6.1 doesn't seem to be vulnerable to this.  Like
NetBSD, It just returns a filename too long error.

anyhow, i remove the suid bit from dump.

--
Eugene Teo - http://www.eugeneteo.net - http://linux.com.sg
Email: eugeneteo () eugeneteo net, eugeneteo () linux com sg

----- Original Message -----
From: ±è¿ëÁØ KimYongJun (99Á¹¾÷) <s96192 () CE HANNAM AC KR>
To: <BUGTRAQ () SECURITYFOCUS COM>
Sent: Monday, February 28, 2000 2:17 PM
Subject: [ Hackerslab bug_paper ] Linux dump buffer overflow

> [ Hackerslab bug_paper ] Linux dump buffer overflow
>
>
> File   :   /sbin/dump
>
> SYSTEM :   Linux
>
>
> INFO :
>
>
> The problem occurs when it gets the argument.
> It accepts the argument without checking out its length, and this causes
the problem.
> It seems that this vulnerability also applies to RedHat Linux 6.2beta,
> the latest version.
>
>
> [loveyou@loveyou SOURCES]$ dump  -f a `perl -e 'print "x" x 556'`
>   DUMP: Date of this level 0 dump: Mon Feb 28 14:45:01 2000
>   DUMP: Date of last level  dump: the epoch
>   DUMP: Dumping
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx to a
>
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx: ÆÄÀÏ À̸§ÀÌ ³Ê¹« ±é´Ï´Ù
while opening filesystem
>   DUMP: SIGSEGV: ABORTING!
> Segmentation fault
>
> [loveyou@loveyou SOURCES]$ dump  -f a `perl -e 'print "loveyou" x 556'`
>   DUMP: SIGSEGV: ABORTING!
> Segmentation fault    <=  occur ctime4()
>
>
> How to fix
> ----------
>
> patch :
>
> [root@loveyou SOURCES]# diff -ru dump-0.4b13/dump/main_orig.c
dump-0.4b13/dump/main.c
> --- dump-0.4b13/dump/main_orig.c        Mon Feb 28 14:40:01 2000
> +++ dump-0.4b13/dump/main.c     Mon Feb 28 14:40:57 2000
> @@ -273,6 +273,9 @@
>                 exit(X_STARTUP);
>         }
>         disk = *argv++;
> +        if ( strlen(disk) > 255 )
> +           exit(X_STARTUP);
> +
>         argc--;
>         if (argc >= 1) {
>                 (void)fprintf(stderr, "Unknown arguments to dump:");
>
>
>
> hot fix :
> it  is recommended that  the suid bit is
> removed from dump using command :
>
>     chmod a-s /sbin/dump
>
>
>
>
> - Yong-jun, Kim -
> e - mail : loveyou () hackerslab org       s96192 () ce hannam ac kr
> homepage : http://www.hackerslab.org    http://ce.hannam.ac.kr/~s96192