The adversary is trying to communicate with compromised systems to control them.
Command and Control consists of techniques that adversaries may use to communicate with systems under their control within a victim network. Adversaries commonly attempt to mimic normal, expected traffic to avoid detection. There are many ways an adversary can establish command and control with various levels of stealth depending on the victim’s network structure and defenses.
| ID | Name | Description | |
| T2065 | Application Layer Protocol | Adversaries may communicate using OSI application layer protocols to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server. | |
| T2066 | Communication Through Cellular Network | Adversaries may communicate using cellular networks in vehicle telematics systems to establish command and control channels. By leveraging the communication capabilities of the telematics box, adversaries can maintain persistent communication with compromised systems. | |
| T2068 | Communication Through Diagnostic Port | Adversaries may communicate using the diagnostic port of a vehicle. Using specialized hardware and software tools, adversaries can connect to the onboard diagnostic (OBD-II) port of a vehicle to send unauthorized commands and extract sensitive information from the vehicle's electronic control units (ECUs). | |
| T2067 | Communication Through Short Range Wireless | Adversaries may communicate using short range wireless communication. Short range wireless technologies such as Bluetooth and Wi-Fi are commonly integrated into modern vehicles to enable features such as hands-free calling, audio streaming, and wireless connectivity. By tapping into these wireless systems, attackers can remotely access vehicular networks within a limit range, often bypassing traditional security measures. | |
| T2069 | Data Encoding | Adversaries may encode data to make the content of command and control traffic more difficult to detect. Command and control (C2) information can be encoded using a standard data encoding system. Use of data encoding may adhere to existing protocol specifications and includes use of ASCII, Unicode, Base64, MIME, or other binary-to-text and character encoding systems. Some data encoding systems may also result in data compression, such as gzip. | |
| T2070 | Data Obfuscation | Adversaries may obfuscate command and control traffic to make it more difficult to detect. Command and control (C2) communications are hidden (but not necessarily encrypted) in an attempt to make the content more difficult to discover or decipher and to make the communication less conspicuous and hide commands from being seen. This encompasses many methods, such as adding junk data to protocol traffic, using steganography, or impersonating legitimate protocols. | |
| T2071 | Dynamic Resolution | Adversaries may dynamically establish connections to command and control infrastructure to evade common detections and remediations. This may be achieved by using malware that shares a common algorithm with the infrastructure the adversary uses to receive the malware's communications. These calculations can be used to dynamically adjust parameters such as the domain name, IP address, or port number the malware uses for command and control. | |
| T2072 | Encrypted Channel | Adversaries may employ a known encryption algorithm to conceal command and control traffic rather than relying on any inherent protections provided by a communication protocol. Despite the use of a secure algorithm, these implementations may be vulnerable to reverse engineering if secret keys are encoded and/or generated within malware samples/configuration files. | |
| T2080 | Non-Application Layer Protocol | Adversaries may use an OSI non-application layer protocol for communication between host and C2 server or among infected hosts within a network. The list of possible protocols is extensive. Specific examples include use of network layer protocols, such as the Internet Control Message Protocol (ICMP), transport layer protocols, such as the User Datagram Protocol (UDP), session layer protocols, such as Socket Secure (SOCKS), as well as redirected/tunneled protocols, such as Serial over LAN (SOL). | |
| T2081 | Non-Standard Port | Adversaries may communicate using a protocol and port pairing that are typically not associated. For example, HTTPS over port 8088 or port 587 as opposed to the traditional port 443. Adversaries may make changes to the standard port used by a protocol to bypass filtering or muddle analysis/parsing of network data. | |
| T2082 | Protocol Tunneling | Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection/network filtering and/or enable access to otherwise unreachable systems. Tunneling involves explicitly encapsulating a protocol within another. This behavior may conceal malicious traffic by blending in with existing traffic and/or provide an outer layer of encryption (similar to a VPN). Tunneling could also enable routing of network packets that would otherwise not reach their intended destination, such as SMB, RDP, or other traffic that would be filtered by network appliances or not routed over the Internet. | |