Configuring TLS Inspection Policy for the Account

This article discusses how to configure and customize the TLS Inspection policy to meet the specific requirements of your network.

Overview of the Cato TLS Inspection Policy

Today most network traffic is encrypted (TLS, HTTPS), which often minimizes the benefit of scanning traffic with IPS, Internet firewall, Application Control Policy and Anti-Malware traffic. If the traffic contains malicious content, it is also encrypted and the Cato security engines can't inspect or scan it.

When you enable TLS Inspection for your account, Cato securely decrypts traffic that passes through a PoP and the Cato security engines inspect it for malware and scan downloaded files. If the content of the traffic is confirmed as safe, Cato then re-encrypts the traffic and forwards it to the destination. However, if the content contains actual or suspected malware, then the Cato security engines block the traffic.

You can choose to use the default Cato policy that inspects all traffic. You can also create specific TLS Inspection rules that define which traffic is inspected and which traffic bypasses TLS Inspection.

tlsinspection.png

Note

Note: By default, TLS Inspection is bypassed for these operating systems:

  • Android (due to issues related to certificate pinning)

  • Linux

  • Unknown operating systems

Cato Implicit Bypass Rule for Applications

Cato includes several applications in an implicit bypass rule that are automatically excluded from TLS Inspection. For a list of these applications, see below Implicitly Bypassed Applications.

Latency for TLS Inspection

Some minimal latency is expected at initial connection due to the TCP and TLS handshakes that occur before data can flow to the appropriate network or security engine in the PoP. This latency is up to 8 milliseconds per packet.

Working with an Ordered TLS Inspection Rule Base

The TLS Inspection engine inspects connections sequentially, and checks to see if the connection matches a rule. The final rule in the rule base is a default ANY - ANY Inspect rule - so if a connection does NOT match a rule, then it is automatically inspected.

You can review the default rule settings in the Default Rules section at the end of the rulebase, but these rules can't be edited.

Rules that are at the top of the rule base have a higher priority because they are applied to connections before the rules lower down in the rule base. For example, if a connection matches on rule #2, the action for this rule is applied to the connection and the TLS Inspection engine stops applying the policy to this connection. This means that rules #3 and below aren't applied to the connection.

Understanding the Actions for TLS Inspection Rules

The TLS Inspection rules let you use an inspect or bypass action for the TLS traffic.

Using Rules that Inspect TLS Traffic

Use the Inspect action to define TLS Inspection rules that decrypt connections and let the relevant security engines inspect the traffic for malicious content.

Using Rules that Bypass TLS Traffic

Use the Bypass action to define the traffic that bypasses TLS Inspection rules. Bypassed traffic isn't decrypted for inspection by the Cato security engines. Remember that a bypass rule only excludes a connection that does NOT match an inspect rule higher in the rule base.

You can change the priority of a bypass rule so that it has a higher priority than an inspect rule.

Configuring the TLS Inspection Policy

Use the TLS Inspection Policy window to configure the TLS Inspection policy for all traffic in your account. You can choose to use the default policy that inspects all traffic, or add inspection and bypass rules to create a custom policy.

Working with Multiple Items

When there are multiple items in a Source, or a What field, such as two groups or categories, then there is an OR relationship between these items. In the example below, the PoP only inspects TLS traffic that originates from the All Sites or the All VPN Users group.

multi-tlsrules.png

Installing the Cato Root Certificate on End-user Devices

The Cato root certificate must be installed as a trusted certificate on every device and computer that connects to the Cato Cloud. For more information about installing the Cato certificate, see Testing TLS Inspection in the Cato Cloud.

  • The Cato certificate can't be installed on most embedded operating systems, therefore many devices using embedded operating systems lose connectivity when TLS Inspection is enabled. For more about supported operating systems, see Best Practices for TLS Inspection.

Blocking QUIC and GQUIC Traffic for TLS Inspection

QUIC and GQUIC are transport protocols developed by Google which don't operate over TCP connections, and traffic using these protocols can't be inspected by the TLS Inspection service. Therefore we recommend that accounts than enable TLS Inspection block QUIC and GQUIC traffic using Internet Firewall rules. The rules that block this traffic force the flow to only connect using protocols that can be inspected by the TLS Inspection service. If you allow traffic using these protocols, the flows can't be inspected and are unnecessarily blocked.

The first time you enable the TLS Inspection policy, rules to block QUIC and GQUIC traffic are automatically added to the Internet Firewall policy. If the Internet Firewall policy already blocks QUIC traffic so that it can be correctly inspected, then no new rules are added.

For more about QUIC and GQUIC traffic, see Internet and WAN Firewall Policies – Best Practices

Using the Default TLS Inspection Policy

The default Cato TLS Inspection policy inspects all traffic (except for the applications that are automatically bypassed). You can use the default policy by enabling TLS Inspection and there is no need to add any rules to the policy.

There is a final implicit rule that matches and all traffic with the Inspect action.

To use the default Cato TLS Inspection policy:

  1. From the navigation menu, click Security > TLS Inspection. The TLS Inspection window opens.

  2. Click the Enable TLS Inspection slider.

  3. Click Save. TLS inspection is enabled using the default policy.

Adding Rules to Customize the TLS Inspection Policy

You can customize the TLS Inspection policy to only inspect the specific traffic types according to the needs of your organization. Add rules to the policy with Inspect and Bypass actions to define which traffic is decrypted and inspected.

  • Create rules with the Inspect action to define traffic that the Cato Cloud inspects for suspicious and malicious content.

  • Create rules with the Bypass action to exclude specific traffic from the Cato TLS inspection engines. For example, you can add a bypass rule for the RingCentral application to exclude RingCentral traffic from TLS Inspection.

When creating rules, use Source and What to define the scope of the TLS traffic and Action to configure whether the rule inspects or bypasses traffic. Make sure that the bypass rule has a higher priority (closer to the top of the rulebase) then an inspect rule that matches the same traffic. Traffic that matches a TLS Inspection bypass rule is also excluded from security scans by the Anti-Malware engines.

Note

Note: For applications that use certificate pinning to prevent TLS inspection, add them to a bypass rule so they will function correctly for the end users.

To add rules to the TLS inspection policy:

  1. From the navigation menu, click Security > TLS Inspection. The TLS Inspection window opens.

  2. Click New. The New panel opens.

  3. Enter a Name for the rule.

  4. Use the Enabled toggle to enable or disable the rule.

    The toggle is green toggle.png when enabled.

  5. Configure the Rule Order for this rule.

  6. In the Source section, enter a string or select one or more object types and then click add.png to define the source.

  7. Define What the rule applies to. For example, a service, an application, a custom or predefined category.

  8. Configure the Action by selecting Inspect or Bypass.

  9. Click Apply. The rule is added.

  10. Click Save. The TLS Inspection rule is saved in the rulebase.

Managing the TLS Inspection Policy

This section explains how to manage the rules in the TLS Inspection policy, including: changing the rule priority, enabling and deleting rules.

Changing the Rule Priority

Change the priority of a rule to determine when the rule action is applied to a matching connection. Rules are applied sequentially to each connection, once a connection matches a rule, the rules with lower priority aren't applied to it.

Enabling and Disabling TLS Inspection Rules

Use the slider to enable and disable individual rules in the TLS Inspection policy.

Deleting Rules

You can delete one or more rules from the TLS Inspection rule base. After you delete the rules, you cannot undo or restore them.

Defining Behavior for Untrusted Server Certificates

The Actions section lets you define the behavior for server certificates that aren't trusted or are revoked. The default setting is the Prompt action and users are shown a prompt asking them to confirm that they want to continue and go to the site with one of the untrusted certificates.

UntrustedServerCertificates.png

To configure the settings for traffic with untrusted certificates:

  1. From the navigation menu, click Security > TLS Inspection. The TLS Inspection window opens.

  2. In the Actions section, from the Untrusted Server Certificates drop-down menu, select the action for traffic with problematic certificates: Allow, Block, or Prompt.

  3. Click Save.

Implicitly Bypassed Applications

The following table lists the applications that are included in an implicit bypass rule for TLS Inspection. This rule is at the top of the rulebase and these applications automatically bypass TLS Inspection (even if you add them to an inspect rule).

For some implicitly bypassed applications, all clients are bypassed except for specific supported browsers for which traffic is inspected, as detailed in the table below.

Application

Comments

 

Adobe

 

 
Agent GPT Reworkd AI

 

 

AIM

 

 

Apple Account

 

 

Apple App Store

 

 

Apple iCloud

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 

Apple software update

 

 

Asana

 

 

Avast

 

 

Bitbucket

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 

Bitdefender

 

 

Bluejeans

 

 

Carbon Black

 

 

Cato Management Application

 

 

Centrify IAM

 

 

Codeload GitHub

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 

Demandbase

 

 

DoubleClick

 

 

Dropbox

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 
Elicit AI

 

 

FilesAnywhere

 

 

HBO

 

 

Google AdWords

 

 

Google Apps

The Google Apps application can impact the following services: Google Search, Google Maps, Google Drive, Google Docs, Google Calendar, Google Hangouts

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac), Safari (Mac)

However, browsers are bypassed for Google Search queries as part of complying with GDPR.

 

Google Bard

 

 

Google+

 

 

Google Search

Bypassed except for the domain googleusercontent.com

 

GoToAssist

 

 

GoToMeeting

 

 

GoToMyPC

 

 

Grammarly

 

 

HBO

 

 

iTunes Streaming

 

 

JetBrains

 

 

KakaoTalk

 

 
Kaspersky

 

 
Lifesize

 

 
LINE

 

 
MagicPen AI

 

 
Mcafee Updater

 

 

MEGA

 

 
Mega io All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)  

Microsoft Azure

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 

Microsoft General

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 

Microsoft Live

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 

Microsoft Login

 

 

Naver Line

 

 

Netflix

 

 

npm

 

 

OneNote

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 

Outlook

The Outlook application is bypassed only on iOS and macOS

 

PCoIP

 

 
Poe AI

 

 
Python PyPi

 

 

Periscope

 

 
Signal Messenger LLC

 

 
Sophos

 

 

Sugarsync

 

 
Symantec End-Point Protection

 

 

TigerText

 

 

Ubuntu

 

 

Visual Studio

 

 

Vudu

 

 

Webex

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 

WhatsApp

All clients are bypassed except for the following: Chrome (Windows), Firefox (Windows), Edge, Chrome (Windows 10 Pro), Chrome (MacOS), Firefox (Unix), Firefox (Mac)

 

Windows Update

 

 

Wire

 

 

Wiredrive

 

 

XMPP

 

 

Zoom

 

 

iOS Bypassed Applications

The applications in this section are bypassed only on iOS:

Application

Comments

Amazon AWS

 

Facebook

 

Gmail

 

Google applications

 

Google Calendar

 

Google Docs

 

Google Drive

 

Google Maps

 

Google+

 

Hangouts for desktop

 

Instagram

 

microsoft_office_login

 

Outlook

 

Reddit

 

Skype

 

Teams

 

Twitter

 

YouTube

 

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