5 Threats to Your Email Server

Email is one of the most popular ways of doing business. In the modern office, nearly all communication flows through email. Everything feeds into it — Slack, JIRA, account notifications — everything. That's why email servers are an easy target for hackers.

Attackers use common methods to discover vulnerabilities on your email server. You definitely need to protect against those. However, protecting your server also is about educating your end users and using the latest tech to protect what you have on hand. We've listed some of the biggest threats to your server that are worth monitoring — for the sake of your organization.

Weak authentication procedures

In most cases, the weakest link is the log-in page. More accurately, it's the credentials entered into the login page. Good authentication protocols and practices truly are your first defense against attackers.

Weak passwords. By having a solid authentication plan in place, you're locking the first place where hackers try to enter. Attackers can easily download lists of phished emails and passwords. They might also use brute force attacks to guess user passwords. So, make it harder for them to be successful.

Encourage your users to go to haveibeenpwned.com/ to see whether their credentials are exposed. They might be surprised by what they discover, highlighting the need for strong passwords.

No 2FA. If an attacker guesses or inputs a correct username and password, two-factor authentication is often enough to stop the attack, since the attacker would need the user's mobile device. Strongly encourage your end users to use two-factor authentication. Even better, require two-factor authentication.

No SSL. Most employees in your organization need to be able to access their email remotely. Ensuring that users can connect securely is also an issue and should be done via encryption using TLS or SSL between the user and the email server. Without encryption, your users could fall victim to a man-in-the-middle attack.

Data leakage

There's always a chance for sensitive data to be leaked, whether that's on a physical device or in the cloud. The frustrating thing is that this still can occur no matter how many security measures your team has in place.

Data leakage comes in different forms: Phishing, malware, or an attacker gaining physical access to your email server. Email accounts can even be breached via stolen mobile devices.

An attacker can send a simple attachment, tricking the user into opening it on a computer. This attachment crawls the network searching for resources and sensitive data. Once the attachment sends the data back to the attacker, all bets are off about what happens with that data.

Attackers might want to delete or destroy it; others may hold it hostage for a ransom. Others could even sell it on the black market.

The good news is that businesses can easily defend against most of the vectors attackers use to steal critical information. For example, remote wiping tools let you delete data on stolen phones.

Email filters installed on your server help defend against spam attacks. A couple of authentication methods help with email spam. Sender Policy Framework (SPF) checks the sender's IP address to make sure it's in a whitelist of allowed senders. DomainKeys Identified Mail (DKIM) checks an email's digital signature distributed via DNS. Author Domain Signing Practices (ADSP) checks the author's domain for verification and then authenticates the sender using DKIM.

Education helps users detect phishing attacks, but these email data security features can actually block phishing emails. Blocking executables and files with malicious macros before they reach the email server is a surefire way to protect that server.

DoS attacks

Denial-of-service (DoS) attacks flood servers with traffic, ruining the reliability of email servers. Typically, DoS involves flooding traffic on a web server causing it to crash. But DoS attacks can use several vectors to cause disruptions on any vulnerable devices.

Your email server is also susceptible to these attacks. An attacker who stops email service can cause major disruptions to both communication and productivity. Several devices offer ways to stop DoS attacks. IDS and IPS systems with firewalls that detect attacks and alert administrators can help prevent DoS attacks.

Old and unnecessary installs

Updating devices and software regularly is the easiest way to protect from attackers. Every operating system and software application needs updates. While these updates often patch bugs in the server's software, some also plug security holes.

When you don't update your software, you leave expose potential vulnerabilities to attackers. Attackers often target outdated software with known vulnerabilities because it's easy.  

Even (maybe especially) Windows comes with applications that aren't necessary. When you ignore bloatware, you risk forgetting to update them with the latest security patches, which could leave your server vulnerable to security issues. Also, unnecessary files accumulate through the normal course of operation.

If you don't need files or software on the server, uninstall them. You'll be freeing up space and memory — and making your server more secure.

Not having enough staff that knows the server

Every IT position has a learning curve. Understanding the configurations, settings, and software specific to your organization takes time. If you don't have staff that's knowledgeable about your server infrastructure, your org could experience productivity and security issues.

Provide your staff time to learn and understand the network infrastructure, and allow dedicated time for training. This will help ensure that you have knowledgeable staff securing your email server in the best way possible.

Email servers are just one piece of the puzzle when it comes to your organization's infrastructure. But considering how crucial they are, you should place a high priority on keeping them secure. They store tons of data for your customers, employees, and the organization. If you take the steps to avoid these five dangers, you harden security for all of your important data.