Exfiltration Over Other Network Medium

Adversaries may attempt to exfiltrate data over a different network medium than the command and control channel. If the command and control network is a wired Internet connection, the exfiltration may occur, for example, over a WiFi connection, modem, cellular data connection, Bluetooth, or another radio frequency (RF) channel.

Adversaries may choose to do this if they have sufficient access or proximity, and the connection might not be secured or defended as well as the primary Internet-connected channel because it is not routed through the same enterprise network.

ID: T1011
Sub-techniques:  T1011.001
Tactic: Exfiltration
Platforms: Linux, Windows, macOS
Contributors: Itzik Kotler, SafeBreach
Version: 1.2
Created: 31 May 2017
Last Modified: 11 September 2023

Mitigations

ID Mitigation Description
M1042 Disable or Remove Feature or Program

Disable WiFi connection, modem, cellular data connection, Bluetooth, or another radio frequency (RF) channel in local computer security settings or by group policy if it is not needed within an environment.

M1028 Operating System Configuration

Prevent the creation of new network adapters where possible.[1][2]

Detection

ID Data Source Data Component Detects
DS0017 Command Command Execution

Monitor executed commands and arguments that may attempt to exfiltrate data over a different network medium than the command and control channel

DS0022 File File Access

Monitor for files being accessed that could be related to exfiltration, such as file reads by a process that also has an active network connection.

DS0029 Network Traffic Network Connection Creation

Monitor for newly constructed network connections that may attempt to exfiltrate data over a different network medium than the command and control channel. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious.

Note: Network Analysis frameworks such as Zeek can be used to capture, decode, and alert on TCP network connection creation. The below analytic is using an event ID from OSQuery.

Analytic 1 - Windows Process Network Connection

netcon_from_sysproc = filter process_open_sockets where remote_port != 0 AND proc_name!= '';"

Network Traffic Content

Monitor and analyze traffic patterns and packet inspection associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).

Network Traffic Flow

Monitor network data for uncommon data flows., such as the usage of abnormal/unexpected protocols.

References