Exfiltration Over Web Service: Exfiltration to Cloud Storage

ID Name
T1567.001 Exfiltration to Code Repository
T1567.002 Exfiltration to Cloud Storage

Adversaries may exfiltrate data to a cloud storage service rather than over their primary command and control channel. Cloud storage services allow for the storage, edit, and retrieval of data from a remote cloud storage server over the Internet.

Examples of cloud storage services include Dropbox and Google Docs. Exfiltration to these cloud storage services can provide a significant amount of cover to the adversary if hosts within the network are already communicating with the service.

ID: T1567.002
Sub-technique of:  T1567
Tactic: Exfiltration
Platforms: Linux, Windows, macOS
Data Sources: Netflow/Enclave netflow, Network protocol analysis, Packet capture, Process monitoring, Process use of network, SSL/TLS inspection
Requires Network:  Yes
Version: 1.0
Created: 09 March 2020
Last Modified: 28 March 2020

Procedure Examples

Name Description
Empire

Empire can use Dropbox for data exfiltration.[1]

HAMMERTOSS

HAMMERTOSS exfiltrates data by uploading it to accounts created by the actors on Web cloud storage providers for the adversaries to retrieve later.[2]

Leviathan

Leviathan has used an uploader known as LUNCHMONEY that can exfiltrate files to Dropbox.[5][6]

Turla

Turla has used WebDAV to upload stolen USB files to a cloud drive.[3] Turla has also exfiltrated stolen files to OneDrive and 4shared.[4]

Mitigations

Mitigation Description
Restrict Web-Based Content

Web proxies can be used to enforce an external network communication policy that prevents use of unauthorized external services.

Detection

Analyze network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server) to known cloud storage services. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious. User behavior monitoring may help to detect abnormal patterns of activity.

References