Communication between Workload Security and the agent

Workload Security and the Deep Security Agent communicate using the latest mutually-supported version of TLS.

Topics in this article:

Configure the heartbeat

A 'heartbeat' is a periodic communication between Workload Security and agent. During a heartbeat, Workload Security collects this information:

  • the status of the drivers (on- or off-line)
  • the status of the agent (including clock time)
  • agent logs since the last heartbeat
  • data to update counters
  • a fingerprint of the agent security configuration (used to determine if it is up to date)

The heartbeat can be configured on a base or parent policy, on a sub-policy, or on an individual computer.

You can configure the following properties of the heartbeat:

  • Heartbeat Interval: How much time passes between heartbeats.
  • Number of Heartbeats that can be missed before an alert is raised: The number of consecutively missed heartbeats that triggers an alert. For example, a value of three causes Workload Security to trigger an alert on the fourth missed heartbeat.)
    If the computer is a server, too many missed heartbeats in a row may indicate a problem with the agent or the computer itself. However if the computer is a laptop or any other system that is likely to experience a sustained loss of connectivity, this setting should be set to "unlimited".
  • Maximum change (in minutes) of the local system time on the computer between heartbeats before an alert is raised: For agents that are capable of detecting changes to the system clock (Windows agents only) these events are reported to Workload Security as agent event 5004. If the change exceeds the clock change listed here then an alert is triggered. For agents that do not support this capability, Workload Security monitors the system time reported by the agent at each heartbeat operation and triggers an alert if it detects a change greater than the permissible change specified in this setting.
    Once a Computer-Clock-Changed alert is triggered, it must be dismissed manually.
  • Raise Offline Errors For Inactive Virtual Machines: Sets whether an offline error is raised if the virtual machine is stopped.
  1. Open the Policy editor or the Computer editor for the policy or computer to configure.
  2. Go to Settings > General > Heartbeat.
  3. Change the properties as required.
  4. Click Save.

Configure communication directionality

For Workload Security, agent-initiated communication is enabled by default and we strongly recommend that you do not change this setting.

Configure whether the agent or Workload Security initiates communication. 'Communication' includes the heartbeat and all other communications. The following options are available:

  • Bidirectional: The agent normally initiates the heartbeat and also listens on the agent's listening port number for connections from Workload Security. (See Workload Security port numbers.) Workload Security can contact the agent to perform required operations. Workload Security can apply changes to the security configuration of the agent.
  • Manager Initiated: Workload Security (the manager) initiates all communication with the agent. These communications include security configuration updates, heartbeat operations, and requests for event logs.
  • Agent Initiated: The agent does not listen for connections from Workload Security. Instead they contact Workload Security on the port number where Workload Security listens for agent heartbeats. (See Workload Security port numbers.) Once the agent has established a TCP connection with Workload Security, all normal communication takes place: Workload Security first asks the agent for its status and for any events. (This is the heartbeat operation.) If there are outstanding operations that need to be performed on the computer (for example, the policy needs to be updated), these operations are performed before the connection is closed. Communications between Workload Security and the agent only occur on every heartbeat. If an agent's security configuration has changed, it is not updated until the next heartbeat.

    For instructions on how to configure agent-initiated activation and use deployments scripts to activate agents, see Activate and protect agents using agent-initiated activation and communication.

To enable communications between Workload Security and the agents, Workload Security automatically implements a (hidden) firewall rule (priority four, Bypass) that opens the listening port number for heartbeats on the agents to incoming TCP/IP traffic. By default, it will accept connection attempts from any IP address and any MAC address. You can restrict incoming traffic on this port by creating a new priority 4, Force Allow or Bypass firewall rule that only allows incoming TCP/IP traffic from specific IP or MAC addresses, or both. This new firewall rule would replace the hidden firewall rule if the settings match these settings:

action: force allow or bypass
priority: 4 - highest
packet's direction: incoming
frame type: IP
protocol: TCP
packet's destination port: agent's listening port number for heartbeat connections from Workload Security, or a list that includes the port number. (See agent listening port number.)

While these settings are in effect, the new rule will replace the hidden rule. You can then type packet source information for IP or MAC addresses, or both, to restrict traffic to the computer.
  1. Open the Policy editor or the Computer editor for the policy or computer to configure.
  2. Go to Settings > General > Communication Direction.
  3. In the Direction of Deep Security Manager to Agent/Appliance communication menu, select one of the three options ("Manager Initiated", "agent/appliance Initiated", or "Bidirectional"), or choose "Inherited". If you select "Inherited", the policy or computer inherits the setting from its parent policy. Selecting one of the other options overrides the inherited setting.
  4. Click Save to apply the changes.
Agents look for Workload Security on the network by the Workload Security hostname. Therefore the Workload Security hostname must be in your local DNS for agent--initiated or bidirectional communication to work.

Supported cipher suites for communication

Workload Security and the agent communicate using the latest mutually-supported version of TLS.

The Deep Security Agent supports the following cipher suites for communication with Workload Security. If you need to know the cipher suites supported by Workload Security, contact Trend Micro.

The cipher suites consist of a key exchange asymmetric algorithm, a symmetric data encryption algorithm and a hash function.

Deep Security Agent 9.5 cipher suites

Deep Security Agent 9.5 (without SPs, patches, or updates) supports these TLS 1.0 cipher suites:

  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA

Deep Security Agent 9.5 SP1 - 9.5 SP1 Patch 3 Update 2 supports these cipher suites:

  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_3DES_EDE_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA

Deep Security Agent 9.5 SP1 Patch 3 Update 3 - 8 supports these cipher suites:

  • TLS_RSA_WITH_AES_256_CBC_SHA256
  • TLS_RSA_WITH_AES_128_GCM_SHA256
  • TLS_RSA_WITH_AES_128_CBC_SHA256
  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA

Deep Security Agent 9.6 cipher suites

Deep Security Agent 9.6 (without SPs, patches, or updates) - 9.6 Patch 1 supports these TLS 1.0 cipher suites:

  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA

Deep Security Agent 9.6 Patch 2 - 9.6 SP1 Patch 1 Update 4 supports these cipher suites:

  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_3DES_EDE_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA

Deep Security Agent 9.6 SP1 Patch 1 Updates 5 - 21 supports these cipher suites:

  • TLS_RSA_WITH_AES_256_CBC_SHA256
  • TLS_RSA_WITH_AES_128_GCM_SHA256
  • TLS_RSA_WITH_AES_128_CBC_SHA256
  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA

Deep Security Agent 10.0 cipher suites

Deep Security Agent 10.0 up to Update 15 supports these TLS 1.2 cipher suites:

  • TLS_RSA_WITH_AES_256_CBC_SHA256
  • TLS_RSA_WITH_AES_128_CBC_SHA256

Deep Security Agent 10.0 Update 16 and later updates supports these TLS 1.2 cipher suites, out-of-box:

  • TLS_RSA_WITH_AES_256_CBC_SHA256
  • TLS_RSA_WITH_AES_128_CBC_SHA256

Deep Security Agent 11.0 cipher suites

Deep Security Agent 11.0 up to Update 4 supports these cipher suites:

  • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
  • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
  • TLS_RSA_WITH_AES_256_CBC_SHA256
  • TLS_RSA_WITH_AES_128_CBC_SHA256

Deep Security Agent 11.0 Update 6 and later updates supports these TLS 1.2 cipher suites:

  • TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
  • TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
  • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
  • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256

Deep Security Agent 12.0 and Deep Security Agent 20 cipher suites

  • TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
  • TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
  • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
  • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256