What is an SSL inspection, and how does it work?
An SSL/TLS inspection is a process that helps protect networks by decrypting and inspecting traffic. While “SSL” (Secure Sockets Layer) is the more commonly known term, it has been succeeded by “TLS” (Transport Layer Security), which offers advanced security features. For simplicity, this article will refer to the process as SSL inspection, but it is important to understand that it includes both the SSL and TLS protocols.
Web servers protect their incoming and outgoing data through SSL encryption, which enables encrypted traffic to move between a client device and the server sending the data. Most sites that enable Hypertext Transfer Protocol Secure (HTTPS) use SSL encryption, ensuring that HTTPS traffic has a high level of user privacy.
The SSL inspection process (also referred to as HTTPS inspection due to its association with HTTPS websites) examines the encrypted traffic being transferred between a web server and a client and scans it for any malicious content. This process is usually done by checking if a web domain’s server certificate is authentic and has been issued by an SSL certificate provider.
Most websites today use SSL’s successor, TLS. However, it’s not uncommon to find websites that use both TLS and SSL, especially if they’re older domains that haven’t been updated with the latest security best practices.
How to set up an SSL inspection
SSL inspections are usually configured by network administrators, who integrate specific security tools and solutions that decrypt incoming network traffic. Once this system is set up, all incoming and outgoing traffic will be subject to automatic SSL inspections, which will decrypt, analyze, and re-encrypt all data that matches the definitions set by the network administrator.
Since this process is triggered automatically to all matching network traffic, HTTPS sites are far more secure than HTTP domains. However, it doesn’t always mean that a site using HTTPS connections is automatically running SSL inspection since it needs to be set up by a network administrator first.
How to check SSL inspection
If you want to check if your connection is undergoing SSL inspection, the best way is to look at the website certificate. If the website certificate isn’t one from a well-known certificate authority (CA), your connection is likely being inspected by an SSL inspection product. SSL inspection is easier to detect if you’re using a device owned by an organization, like your work computer or laptop.
Another approach that companies and organizations can use with their issued devices is running a specific SSL inspection product (usually endpoint software like a web security gateway) to monitor a device’s incoming and outgoing traffic. You can detect SSL inspection by opening the list of currently running processes on your device and looking for programs you don’t recognize. However, this step may be difficult if you don’t have administrator privileges on your device.
Is an SSL inspection worth it?
Aside from verifying encrypted traffic flowing in and out of a network, you can gain three main benefits from conducting an SSL inspection:
- Better filtering of malicious content: Malicious content, such as viruses or malware, hiding within SSL traffic can be flagged with an SSL inspection, which increases connection security and better protects a network from bad actors.
- Application-specific security measures: SSL inspections can scan applications that use SSL or HTTPS traffic. This capability allows network administrators to set routing policies or implement security measures based on specific application needs.
- Unsafe or malicious URL blocking: SSL inspection can also help block specific websites flagged for malicious and/or forbidden content. This capability can be useful for organizations that can’t risk connections to potentially dangerous or distracting websites.
Overall, SSL inspection offers a great way to ensure that the SSL traffic coming into your device (or the data that you send to a website or web server) is free of malicious content. SSL inspection ensures your encrypted traffic isn’t used as a gateway for cyberattacks. In combination with a firewall and other security protocols, SSL inspection is an excellent way to ensure your data remains secure.
What are the risks of an SSL inspection?
Some drawbacks and risks when you inspect SSL traffic may include:
- A compromised CA: If the entity assigning SSL certificates experiences an attack that causes it to issue unauthorized (but still trusted) SSL certificates, attackers may bypass SSL inspections by impersonating legitimate domains.
- Issues with decrypted traffic: Since the SSL inspection process must decrypt SSL traffic, this creates a window that attackers can exploit to steal data, plant malicious content, or affect the data flow.
- Unpatched vulnerabilities: SSL encrypted data should ideally follow the latest SSL protocols. However, some SSL inspection products may not be updated with the latest security patches.
- Other interruptions to the SSL inspection process: If the SSL inspection process is interrupted at any point, the unencrypted SSL traffic is vulnerable to hackers who may be monitoring the data transfer between networks.
How to stop an SSL inspection
If you’re trying to disable SSL inspections, the required settings are usually found under their security profiles, management consoles, or any section that controls secure connections like SSL. You can either toggle the option off or add a rule that exempts specific domains or web servers.
However, most security experts don’t recommend turning off SSL inspection. While potential concerns about security gaps exist as discussed above, SSL inspection still remains the best way for you to make sure that encrypted traffic incoming or outgoing from your network doesn’t contain malicious data or content.
