T1041 Exfiltration Over C2 Channel

Network intrusion prevention solutions can use malware- and protocol-specific signatures to block identifiable exfiltration occurring over command-and-control channels.

This technique may be mitigated depending on where ingress and egress is tightly controlled. For example, the use network signatures such as IP addresses or domain names to identify traffic for specific adversary malware can be used to mitigate activity at the network level.

DLP is a direct control for blocking or alerting on exfiltration and data staging behaviors. DLP solutions explicitly monitor and restrict unauthorized outbound transfer of sensitive data.

Often used by adversaries to compromise sensitive data, Palo Alto Network's spyware signatures is able to detect data exfiltration attempts and anomalies over known command and control communications. Although there are ways an attacker could still exfiltrate data from a compromised system, this technique was scored as significant based on Palo Alto Network's advanced threat detection technology which constantly updates to detect against the latest known variations of these attacks.

Cloud NGFW can allow or deny traffic based on the traffic's protocol, destination ports, sources, and destinations. This functionality can be used to block adversaries from accessing resources from which to exfiltrate data as well as prevent resources from communicating with known-bad IP addresses and domains that might be used to receive exfiltrated data. This mapping is given a score of Partial because the known-bad IP addresses and domains would need to be known in advance.

Google Security Ops is able to trigger an alert based off suspicious system processes or command-line arguments that could indicate exfiltration of data over the C2 channel. This technique was scored as minimal based on low or uncertain detection coverage factor. https://github.com/chronicle/detection-rules/blob/783e0e5947774785db1c55041b70176deeca6f46/soc_prime_rules/threat_hunting/sysmon/possible_data_exfiltration_via_smtp.yaral https://github.com/chronicle/detection-rules/blob/783e0e5947774785db1c55041b70176deeca6f46/soc_prime_rules/threat_hunting/windows/data_exfiltration_attempt_via_bitsadmin.yaral

The following AWS IoT Device Defender device-side detection metrics can detect indicators that an adversary may be exfiltrating collected data from compromised AWS IoT devices using an established command and control channel to/from those devices: "Destination IPs" ("aws:destination-ip-addresses") outside of expected IP address ranges may suggest that a device is communicating with unexpected parties. "Bytes in" ("aws:all-bytes-in"), "Bytes out" ("aws:all-bytes-out"), "Packets in" ("aws:all-packets-in"), and "Packets out" ("aws:all-packets-out") values outside of expected norms may indicate that the device is sending and/or receiving non-standard traffic, which may include exfiltration of stolen data. "Listening TCP ports" ("aws:listening-tcp-ports"), "Listening TCP port count" ("aws:num-listening-tcp-ports"), "Established TCP connections count" ("aws:num-established-tcp-connections"), "Listening UDP ports" ("aws:listening-udp-ports"), and "Listening UDP port count" ("aws:num-listening-udp-ports") values outside of expected norms may indicate that devices are communicating via unexpected ports/protocols, which may include exfiltration of data over command and control channels. Coverage factor is partial, since these metrics are limited to exfiltration from IoT devices, resulting in an overall score of Partial.

AWS Network Firewall has the ability to pass, drop, or alert on traffic based on the network protocol as well as perform deep packet inspection on the payload. This functionality can be used to block adversaries from accessing resources from which to exfiltrate data as well as prevent resources from communicating with known-bad IP addresses and domains that might be used to receive exfiltrated data. This mapping is given a score of Partial because the known-bad IP addresses and domains would need to be known in advance.

The following GuardDuty finding type flags events that may indicate adversaries attempting to exfiltrate data, such as sensitive documents. Behavior:EC2/TrafficVolumeUnusual Accuracy and Coverage is unknown, as this finding flags traffic volume that differs from a baseline.