Enterprise-Class SSL and TLS Decryption: Why You Need to See the Unseeable

By Corey Wilburn

If asked, nearly every customer would prefer that their communications, and those of their employees and clients, be as private and secure as possible. That’s the point of using strong encryption. However, there is a dark side: According to a study by A10 Networks and Ponemon, titled “Uncovering Hidden Threats Within Encrypted Traffic,” about 67 percent of Internet traffic was encrypted in 2016, up from 29 percent in 2015. And, among respondents to the study who said they were victims of a cyberattack in the preceding 12 months, nearly half claimed the attack leveraged SSL traffic to evade detection.

Other security studies, including the SonicWall annual report, also show that encrypted data is becoming an easy and increasingly common way to conceal malware, viruses and other damaging content. It’s safe to assume that more than half of encrypted traffic contains something unwanted or dangerous. 

What’s even more concerning is that, as more companies become focused on and anxious about security, and more stories spread about the scary things out there trying to steal your data, many tech watchers expect to see even more encryption, perhaps more than 70 percent of all Internet traffic in the next year.

It’s clearly worth advising customers to be cautious and ask: Why is this entity sending me a file using strong encryption? Are they doing something dangerous, illegal or generally up to no good? Are they plotting against us? Without SSL inspection in place to answer those questions, a business could fall victim to the kind of encrypted traffic that has malicious intent behind it.

We Need More Visibility

Many standard firewalls can’t see what’s inside encrypted data packets. Rather than drop them, packets are often “waved in” without being thoroughly inspected by antivirus tools or other monitoring systems. Once inside a customer’s environment, delivered to an endpoint and clicked on by an unsuspecting target, the malicious payload is free to run amok and wreak havoc.

More and more firewalls do contain methods to decrypt traffic as it passes through, but this feature is often considered an add-on, with an extra cost, and is limited in its ability to properly handle decrypting a large amount of inbound/outbound traffic. The decryption and encryption process takes a fair amount of computational overhead, depending the strength of the encryption. Processing these tasks on a machine that is also doing many other functions can create bottlenecks and reduce the availability of networking services.

We know the problem. What’s the answer?

My company, IT solutions provider Data Endure, works with some top security providers, including Symantec. While most notable as a market leader in personal and enterprise antivirus products, AV is not the only game Symantec plays. Over the years it has continued to grow its pool of technologies via internal development and acquisitions. Today, the company offers other useful protections against more advanced threats, including email and advanced security challenges.

Symantec recently acquired Blue Coat, which brings us to the conversation of hardware and software solutions that are mainly geared to manage encrypted traffic. Blue Coat was a market leader in the arena of SSL decryption and built a great business tackling that problem for its customers. While there are a number of firewalls that do SSL interception and inspection of encrypted traffic, I’ll use the Symantec/Blue Coat product set as my example of what to look for, because we partner with them.

Symantec’s flagship product, Proxy SG, sits as a decryption proxy in the customer environment, comes packed with useful features and is deployable in both on-premises and cloud models. You can tune intelligent policy decisions for customers based on reputation, whitelist and blacklist methodologies so that you are selectively decrypting, blocking or allowing traffic while at the same time protecting your customer’s privacy. For example, say the company allows end users to log in to their online banking applications while in the office; you could set the proxy to pass that through traffic untouched.

The acquisition of Blue Coat is also expanding Symantec’s coverage in the realms of reputation-based decisions, updates and automatic tuning of the system.

Symantec’s Global Intelligence Network, always a bit of secret sauce for partners, is a global array of sensors that feed threat telemetry back to the mother ship. This real-time threat information is then tapped into by a few of Symantec’s core products. Blue Coat’s integration into Symantec’s Global Intelligence Network will be a win-win on both technology fronts. (A look at the combined Symantec Secure One and Blue Coat partner program is here.)

It’s important to remember that integrating a technology such as this into a customer network should not be done lightly. Come prepared, and get some outside help if you need it. There is a good amount tuning required, not to mention focused conversations on what the company’s decryption policy is going to be. But one thing is for sure: It’s time to talk to customers about the dark side of encryption.

Corey Wilburn is the security practice manager at DataEndure, where he specializes in the design of strategic solutions, aimed at delivering high-value operational intelligence, leveraging best-in-class products as well as services built around current and emerging standards.