TLS 1.3: A Good News/Bad News Scenario

A growing number of blog posts and news stories are being written about the impact of the relatively new TLS 1.3 transport encryption standard, and for good reason. While TLS 1.3 enables much better end-to-end privacy, it can break existing security controls in enterprise networks that rely on the ability to decrypt traffic in order to perform deep-packet inspection to look for malware and evidence of malicious activity. Well-known examples of those security controls include next-generation firewalls, intrusion prevention systems, sandboxes, network forensics, and network-based security analytics products.

These security controls rely on access to a static, private key in order to decrypt traffic for inspection. The use of such keys is replaced in TLS 1.3 by the requirement to use the Diffie-Hellman Ephemeral perfect forward secrecy key exchange. That exchange occurs for each session or conversation that is established between endpoints and servers. In addition, the certificate itself is encrypted, which denies those tools access to valuable metadata for additional analysis.

The ephemeral key exchange is not new to TLS. TLS 1.2 also included it as an option. In TLS 1.3, it is required. Because TLS 1.3 restricts the ability that existing security controls and network performance troubleshooting tools need to peer into packets to perform properly, you'd think that enterprise enablement of the new TLS 1.3 standard would be relatively slow and cautious — akin to the adoption rate after IPv6 was finalized. In fact, the opposite is true. New research, TLS 1.3 Adoption in the Enterprise: Growing Encryption Use Extends to New Standard, published recently by Enterprise Management Associates (EMA), shows that enterprises are rapidly adopting the new specification, which was actually 10 years in the making.

In a survey conducted in late 2018, of 249 IT and IT security respondents in organizations primarily serving North America, 40% say they were already working to enable TLS 1.3 for internal network traffic, and 32% were already enabling it for inbound connections. Another 34% are planning to enable TLS 1.3 for internal traffic in the following six months, while 41% plan to enable it for inbound connections in that time frame. 

Security and Operational Issues
Despite the bullish adoption rate, respondents voice concerns about security and performance monitoring implications of the new standard. Only about 8% of respondents say they had no concerns over implementing TLS 1.3 from a security and operations perspective. Another 22% say they had "significant" concerns about both security and operations, and 40% report "some" concerns about security.

Why the disconnect? There are a few possible explanations:

Multiple studies in the past have shown a steady increase in the use of encryption across the Internet as well as within enterprise networks. The EMA study validates those earlier findings. For example, 31% of respondents indicate that their organization's use of encryption rose between 26% to 50% over the last 18 months. That trend will continue. Unfortunately, bad actors are also increasing their use of encryption to hide their tracks as they get past existing security controls and move laterally within enterprise networks in search of valuable data to exfiltrate. 

Clearly, the need for visibility into network traffic is not going to go away, even though stronger encryption standards are improving the privacy of data in motion. Enterprises will find that they have to adapt their security architectures to work with the new standard in order to maintain that visibility. How they will accomplish that remains to be seen.  

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