8.5. SSH Inspection

The administrator can use this section to configure the inspection of data transmitted using the SSH (Secure Shell) protocol. SSH also allows encrypted tunnels to be created for virtually any network protocol.

The rules in this section can inspect SSH traffic for specific users and/or user groups, source or destination zones or addresses, as well as service types that transmit traffic via the SSH tunnel. There is a feature called Time sets that can be used to apply each rule depending on the day of the week and time of the day.

Note

The rules are applied top to bottom in their listing order. Only the first rule in which all conditions are matched is applied. This means that more specific rules must be placed higher in the list than more general ones. To change the order in which the rules will be applied, use the Up/Down and Top/Bottom buttons or drag and drop the rules with the mouse.

Note

The Negate checkbox changes the condition to the opposite, which corresponds to a Boolean NOT (negation).

Note

If there are no rules created or all rules are disabled, SSH traffic is not intercepted or decrypted, and therefore the data transmitted using SSH is not inspected.

To enable SSH content inspection, follow these steps:

Task

Description

Step 1. Allow the SSH proxy service in the desired zone.

In the Network --> Zones section, allow the SSH proxy service for the zone from which SSH traffic will originate.

Step 2. Create the desired SSH inspection rules.

An SSH inspection rule defines the criteria and actions applied to SSH traffic.

To create an SSH inspection rule, go to the Security policies --> SSH inspection section, click Add, and provide the desired settings.

Name

Description

Enabled

Enables or disables the rule.

Name

The name of the rule.

Description

A description of the rule.

Action

Whether to decrypt data in transit.

Enable logging

Record instances of the rule being triggered in the corresponding statistics log.

Block SSH remote shell

Block a remote user from launching the shell (command line interpreter).

Block SSH remote execution

Block a remote user from running any commands or scripts via SSH.

Edit SSH commands

The Linux command to transmit in the format

ssh user@host 'command'

Example:

ssh root@192.168.1.1 reboot

Block SFTP

Block SFTP (Secure File Transfer Protocol) connections.

Place to

The place in the rule list where this rule will be inserted: at the top, at the bottom, or above the selected existing rule.

Users

The list of users and groups to which this rule is applied. The Any, Unknown, and Known user types can be used. To apply rules to specific users or Known users, user identification needs to be configured. For more details on user identification, see the chapter Users and Devices.

Source

The source zones and/or IP address lists for the traffic.

Important! There is a limit on the number of GeoIPs that can be specified: the number cannot exceed 15.

Important! Traffic processing performed with the following statements:

  • applying logic OR if several IP lists and/or domain lists are specified;

  • applying logic AND if several GeoIP and lists of IPs and/or domains are specified.

For more details on working with IP address lists, see the chapter IP addresses.

Destination address

The lists of destination IP addresses for the traffic.

Important! There is a limit on the number of GeoIPs that can be specified: the number cannot exceed 15.

Important! Traffic processing performed with the following statements:

  • applying logic OR if several IP lists and/or domain lists are specified;

  • applying logic AND if several GeoIP and lists of IPs and/or domains are specified.

For more details on working with IP address lists, see the chapter IP addresses.

Service

The service for which traffic is to be decrypted. This field is required.

Time

The time period in which this rule is active. You can add different types of time period in the Time sets section.

Usage

The rule triggering statistics: the total number of triggers, the time of the first and last triggers.

To reset statistics, select rules in the list and click Reset hit counts.

History

The time when the rule was created and last modified, as well as the event log entries related to this rule: adding, updating the rule, changing the position of the rule in the list, etc.