This site has been deprecated in favor of and will remain in place until 11/1/22.

Block Reporting Message

From attackics
Jump to navigation Jump to search

To visit this technique’s new page please go to and update your links to

Block Reporting Message
ID T0804
Tactic Inhibit Response Function
Data Sources Network Traffic: Network Traffic Flow, Network Traffic: Network Connection Creation, Application Log: Application Log Content, Process: Process Termination, Operational Databases: Process History/Live Data, Operational Databases: Process/Event Alarm
Asset Field Controller/RTU/PLC/IED, Input/Output Server, Device Configuration/Parameters 


Adversaries may block or prevent a reporting message from reaching its intended target. In control systems, reporting messages contain telemetry data (e.g., I/O values) pertaining to the current state of equipment and the industrial process. By blocking these reporting messages, an adversary can potentially hide their actions from an operator.

Blocking reporting messages in control systems that manage physical processes may contribute to system impact, causing inhibition of a response function. A control system may not be able to respond in a proper or timely manner to an event, such as a dangerous fault, if its corresponding reporting message is blocked.12

Procedure Examples

  • In the Ukraine 2015 Incident, Sandworm Team blocked reporting messages by using malicious firmware to render communication devices inoperable.2
  • Industroyer uses the first COM port from the configuration file for the communication and the other two COM ports are opened to prevent other processes accessing them. This may block processes or operators from getting reporting messages from a device.3


  • Network Allowlists - Utilize network allowlists to restrict unnecessary connections to network devices (e.g., comm servers, serial to ethernet converters) and services, especially in cases when devices have limits on the number of simultaneous sessions they support.
  • Out-of-Band Communications Channel - Provide an alternative method for sending critical report messages to operators, this could include using radio/cell communication to obtain messages from field technicians that can locally obtain telemetry and status data.
  • Static Network Configuration - Unauthorized connections can be prevented by statically defining the hosts and ports used for automation protocol connections.