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Virtualization/Sandbox Evasion: User Activity Based Checks
Other sub-techniques of Virtualization/Sandbox Evasion (3)
| ID | Name |
|---|---|
| T1497.001 | System Checks |
| T1497.002 | User Activity Based Checks |
| T1497.003 | Time Based Evasion |
Adversaries may employ various user activity checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from Virtualization/Sandbox Evasion during automated discovery to shape follow-on behaviors.
Adversaries may search for user activity on the host based on variables such as the speed/frequency of mouse movements and clicks [1] , browser history, cache, bookmarks, or number of files in common directories such as home or the desktop. Other methods may rely on specific user interaction with the system before the malicious code is activated, such as waiting for a document to close before activating a macro [2] or waiting for a user to double click on an embedded image to activate.[3]
Procedure Examples
| Name | Description |
|---|---|
| FIN7 |
FIN7 used images embedded into document lures that only activate the payload when a user double clicks to avoid sandboxes.[3] |
| Okrum |
Okrum loader only executes the payload after the left mouse button has been pressed at least three times, in order to avoid being executed within virtualized or emulated environments.[4] |
Mitigations
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Detection
User activity-based checks will likely occur in the first steps of an operation but may also occur throughout as an adversary learns the environment. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as lateral movement, based on the information obtained. Detecting actions related to virtualization and sandbox identification may be difficult depending on the adversary's implementation and monitoring required. Monitoring for suspicious processes being spawned that gather a variety of system information or perform other forms of Discovery, especially in a short period of time, may aid in detection.