Virtualization/Sandbox Evasion: System Checks
Adversaries may employ various system 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.
Specific checks may will vary based on the target and/or adversary, but may involve behaviors such as Windows Management Instrumentation, PowerShell, System Information Discovery, and Query Registry to obtain system information and search for VME artifacts. Adversaries may search for VME artifacts in memory, processes, file system, hardware, and/or the Registry. Adversaries may use scripting to automate these checks into one script and then have the program exit if it determines the system to be a virtual environment.
Checks could include generic system properties such as uptime and samples of network traffic. Adversaries may also check the network adapters addresses, CPU core count, and available memory/drive size.
Other common checks may enumerate services running that are unique to these applications, installed programs on the system, manufacturer/product fields for strings relating to virtual machine applications, and VME-specific hardware/processor instructions. In applications like VMWare, adversaries can also use a special I/O port to send commands and receive output.
Hardware checks, such as the presence of the fan, temperature, and audio devices, could also be used to gather evidence that can be indicative a virtual environment. Adversaries may also query for specific readings from these devices.
GravityRAT uses WMI to check the BIOS and manufacturer information for strings like "VMWare", "Virtual", and "XEN" and another WMI request to get the current temperature of the hardware to determine if it's a virtual machine environment. 
OopsIE performs several anti-VM and sandbox checks on the victim's machine. One technique the group has used was to perform a WMI query
PoetRAT checked the size of the hard drive to determine if it was being run in a sandbox environment. In the event of sandbox detection, it would delete itself by overwriting the malware scripts with the contents of "License.txt" and exiting.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Virtualization/sandbox related system 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.
- Roccia, T. (2017, January 19). Stopping Malware With a Fake Virtual Machine. Retrieved April 17, 2019.
- Falcone, R., et al. (2018, September 04). OilRig Targets a Middle Eastern Government and Adds Evasion Techniques to OopsIE. Retrieved September 24, 2018.
- Hromcova, Z. (2019, October). AT COMMANDS, TOR-BASED COMMUNICATIONS: MEET ATTOR, A FANTASY CREATURE AND ALSO A SPY PLATFORM. Retrieved May 6, 2020.
- Bar, T., Conant, S. (2017, October 20). BadPatch. Retrieved November 13, 2018.
- Dahan, A. (2017). Operation Cobalt Kitty. Retrieved December 27, 2018.
- Symantec Security Response. (2015, June 23). Dyre: Emerging threat on financial fraud landscape. Retrieved August 23, 2018.
- hasherezade. (2015, November 4). A Technical Look At Dyreza. Retrieved June 15, 2020.
- Marschalek, M.. (2014, December 16). EvilBunny: Malware Instrumented By Lua. Retrieved June 28, 2019.
- Allievi, A.,Flori, E. (2018, March 01). FinFisher exposed: A researcher’s tale of defeating traps, tricks, and complex virtual machines. Retrieved July 9, 2018.
- Adamitis, D. et al. (2019, June 4). It's alive: Threat actors cobble together open-source pieces into monstrous Frankenstein campaign. Retrieved May 11, 2020.
- Mercer, W., Rascagneres, P. (2018, April 26). GravityRAT - The Two-Year Evolution Of An APT Targeting India. Retrieved May 16, 2018.
- Hromcova, Z. and Cherpanov, A. (2020, June). INVISIMOLE: THE HIDDEN PART OF THE STORY. Retrieved July 16, 2020.
- Hromcova, Z. (2019, July). OKRUM AND KETRICAN: AN OVERVIEW OF RECENT KE3CHANG GROUP ACTIVITY. Retrieved May 6, 2020.
- Dumont, R.. (2019, April 9). OceanLotus: macOS malware update. Retrieved April 15, 2019.
- Lancaster, T., Idrizovic, E. (2017, June 27). Paranoid PlugX. Retrieved April 19, 2019.
- Mercer, W, et al. (2020, April 16). PoetRAT: Python RAT uses COVID-19 lures to target Azerbaijan public and private sectors. Retrieved April 27, 2020.
- Nicolas Verdier. (n.d.). Retrieved January 29, 2018.
- Brumaghin, E., Unterbrink, H. (2018, August 22). Picking Apart Remcos Botnet-In-A-Box. Retrieved November 6, 2018.
- Falcone, R., et al. (2018, July 27). New Threat Actor Group DarkHydrus Targets Middle East Government. Retrieved August 2, 2018.
- Lee, B., Falcone, R. (2019, January 18). DarkHydrus delivers new Trojan that can use Google Drive for C2 communications. Retrieved April 17, 2019.
- Mercer, W., Rascagneres, P. (2018, January 16). Korea In The Crosshairs. Retrieved May 21, 2018.
- Pantazopoulos, N.. (2018, November 8). RokRat Analysis. Retrieved May 21, 2020.
- Baker, B., Unterbrink H. (2018, July 03). Smoking Guns - Smoke Loader learned new tricks. Retrieved July 5, 2018.
- MSTIC. (2020, December 18). Analyzing Solorigate, the compromised DLL file that started a sophisticated cyberattack, and how Microsoft Defender helps protect customers . Retrieved January 5, 2021.
- Ivanov, A. et al.. (2018, May 7). SynAck targeted ransomware uses the Doppelgänging technique. Retrieved May 22, 2018.
- Bettencourt, J. (2018, May 7). Kaspersky Lab finds new variant of SynAck ransomware using sophisticated Doppelgänging technique. Retrieved May 24, 2018.
- Secureworks. (2019, July 24). Updated Karagany Malware Targets Energy Sector. Retrieved August 12, 2020.
- Hayashi, K. (2017, November 28). UBoatRAT Navigates East Asia. Retrieved January 12, 2018.
- Schwarz, D., Sopko J. (2018, March 08). Donot Team Leverages New Modular Malware Framework in South Asia. Retrieved June 11, 2018.