The following are 3 security threats to SMTP Server: 1. One SMTP Server security threat is called a brute force attack. This security threat is identified by the way in which the attacker tries to break security. This is done by trying to guess the password through the mail server or other service working on your system using software that will use all possible combinations for the password until it guesses the correct one. (Hampton, 2011) 2. Another SMTP Server security threat is denial-of-service also known as DoS. This attack will shut off access to your site. The attacker will increase traffic on your site. The increased traffic will cause your site to become unresponsive and shut down. (Hampton, 2011) 3. Another SMTP Server security threat is malware. Malware is malicious software which can be in various forms such as trojans, viruses, spyware and worms. Malware is usually installed without the user’s consent. It can attack the user’s computer and then use the user’s computer to attack other computers. To help prevent the spread of malware, you can have firewalls and proper security software protection. (Hampton, 2011)
The following are 3 suggestions to harden SMTP Server security: 1. Digitally sign and Encrypt your Email. By doing this you will prevent others from the ability to open and read your email. This will ensure that it is only opened by the person you sent it to. (Ehamouda, 2009) 2. Backup your Exchange server periodically. By doing this you will have copies of everything on your computer to use in case you need to reinstall if your computer crashes due to an attack. (Ehamouda, 2009) 3. Deploy Front End Server: Deploy a Front End Server on the DMZ, and close unused ports on the DMZ. Here are the ports most used by Exchange services:
SMTP 25
DNS 53
HTTP 80
Kerberos 88
POP3 110
NNTP 119
RPC EndPoint Mapper 135
IMAP4 143
LDAP 389
Global Catalog 3268 /9