T0803 Block Command Message
Adversaries may block a command message from reaching its intended target to prevent command execution. In OT networks, command messages are sent to provide instructions to control system devices. A blocked command message can inhibit response functions from correcting a disruption or unsafe condition. 1 2
| Item | Value |
|---|---|
| ID | T0803 |
| Sub-techniques | |
| Tactics | TA0107 |
| Platforms | Device Configuration/Parameters, Field Controller/RTU/PLC/IED |
| Version | 1.0 |
| Created | 21 May 2020 |
| Last Modified | 24 October 2022 |
Procedure Examples
| ID | Name | Description |
|---|---|---|
| S0604 | Industroyer | In Industroyer the first COM port from the configuration file is used for the actual communication and the two other COM ports are just opened to prevent other processes accessing them. Thus, the IEC 101 payload component is able to take over and maintain control of the RTU device. 3 |
| G0034 | Sandworm Team | In the Ukraine 2015 Incident, Sandworm Team blocked command messages by using malicious firmware to render communication devices inoperable. 2 |
Mitigations
| ID | Mitigation | Description |
|---|---|---|
| M0807 | 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. |
| M0810 | Out-of-Band Communications Channel | Provide an alternative method for sending critical commands message to outstations, this could include using radio/cell communication to send messages to a field technician that physically performs the control function. |
| M0814 | Static Network Configuration | Unauthorized connections can be prevented by statically defining the hosts and ports used for automation protocol connections. |
Detection
| ID | Data Source | Data Component |
|---|---|---|
| DS0015 | Application Log | Application Log Content |
| DS0029 | Network Traffic | Network Traffic Flow |
| DS0040 | Operational Databases | Process History/Live Data |
| DS0009 | Process | Process Termination |
References
-
Bonnie Zhu, Anthony Joseph, Shankar Sastry 2011 A Taxonomy of Cyber Attacks on SCADA Systems Retrieved. 2018/01/12 ↩
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Electricity Information Sharing and Analysis Center; SANS Industrial Control Systems 2016, March 18 Analysis of the Cyber Attack on the Ukranian Power Grid: Defense Use Case Retrieved. 2018/03/27 ↩↩
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Anton Cherepanov, ESET 2017, June 12 Win32/Industroyer: A new threat for industrial control systems Retrieved. 2017/09/15 ↩