Hide Artifacts: Hidden Window
Adversaries may use hidden windows to conceal malicious activity from the plain sight of users. In some cases, windows that would typically be displayed when an application carries out an operation can be hidden. This may be utilized by system administrators to avoid disrupting user work environments when carrying out administrative tasks.
On Windows, there are a variety of features in scripting languages in Windows, such as PowerShell, Jscript, and Visual Basic to make windows hidden. One example of this is
powershell.exe -WindowStyle Hidden. 
Similarly, on macOS the configurations for how applications run are listed in property list (plist) files. One of the tags in these files can be
apple.awt.UIElement, which allows for Java applications to prevent the application's icon from appearing in the Dock. A common use for this is when applications run in the system tray, but don't also want to show up in the Dock.
Adversaries may abuse these functionalities to hide otherwise visible windows from users so as not to alert the user to adversary activity on the system.
Limit or restrict program execution using anti-virus software. On MacOS, allowlist programs that are allowed to have the plist tag. All other programs should be considered suspicious.
Monitor processes and command-line arguments for actions indicative of hidden windows. In Windows, enable and configure event logging and PowerShell logging to check for the hidden window style. In MacOS, plist files are ASCII text files with a specific format, so they're relatively easy to parse. File monitoring can check for the
apple.awt.UIElement or any other suspicious plist tag in plist files and flag them.
- Wheeler, S. et al.. (2019, May 1). About PowerShell.exe. Retrieved October 11, 2019.
- Thomas Reed. (2017, January 18). New Mac backdoor using antiquated code. Retrieved July 5, 2017.
- Jazi, H. (2020, April 16). New AgentTesla variant steals WiFi credentials. Retrieved May 19, 2020.
- Ahl, I. (2017, June 06). Privileges and Credentials: Phished at the Request of Counsel. Retrieved May 17, 2018.
- Lee, B., Falcone, R. (2018, June 06). Sofacy Group’s Parallel Attacks. Retrieved June 18, 2018.
- Sherstobitoff, R., Rea, M. (2017, November 7). Threat Group APT28 Slips Office Malware into Doc Citing NYC Terror Attack. Retrieved November 21, 2017.
- Moran, N., et al. (2014, November 21). Operation Double Tap. Retrieved January 14, 2016.
- Carr, N.. (2017, May 14). Cyber Espionage is Alive and Well: APT32 and the Threat to Global Corporations. Retrieved June 18, 2017.
- Dahan, A. (2017). Operation Cobalt Kitty. Retrieved December 27, 2018.
- Salem, E. (2019, February 13). ASTAROTH MALWARE USES LEGITIMATE OS AND ANTIVIRUS PROCESSES TO STEAL PASSWORDS AND PERSONAL DATA. Retrieved April 17, 2019.
- Sardiwal, M, et al. (2017, December 7). New Targeted Attack in the Middle East by APT34, a Suspected Iranian Threat Group, Using CVE-2017-11882 Exploit. Retrieved December 20, 2017.
- ClearSky Cyber Security and Trend Micro. (2017, July). Operation Wilted Tulip: Exposing a cyber espionage apparatus. Retrieved August 21, 2017.
- Falcone, R., et al. (2018, July 27). New Threat Actor Group DarkHydrus Targets Middle East Government. Retrieved August 2, 2018.
- Alperovitch, D. (2014, July 7). Deep in Thought: Chinese Targeting of National Security Think Tanks. Retrieved November 12, 2014.
- Falcone, R., et al. (2018, August 02). The Gorgon Group: Slithering Between Nation State and Cybercrime. Retrieved August 7, 2018.
- FireEye Labs. (2015, July). HAMMERTOSS: Stealthy Tactics Define a Russian Cyber Threat Group. Retrieved September 17, 2015.
- PT ESC Threat Intelligence. (2020, June 4). COVID-19 and New Year greetings: an investigation into the tools and methods used by the Higaisa group. Retrieved March 2, 2021.
- Knight, S.. (2020, April 16). VMware Carbon Black TAU Threat Analysis: The Evolution of Lazarus. Retrieved May 1, 2020.
- Hromcova, Z. and Cherpanov, A. (2020, June). INVISIMOLE: THE HIDDEN PART OF THE STORY. Retrieved July 16, 2020.
- Parys, B. (2017, February 11). The KeyBoys are back in town. Retrieved June 13, 2019.
- Bermejo, L., et al. (2017, June 22). Following the Trail of BlackTech’s Cyber Espionage Campaigns. Retrieved May 5, 2020.
- Lee, B. and Falcone, R. (2017, February 15). Magic Hound Campaign Attacks Saudi Targets. Retrieved December 27, 2017.
- Secureworks. (2019, July 24). MCMD Malware Analysis. Retrieved August 13, 2020.
- Erlich, C. (2020, April 3). The Avast Abuser: Metamorfo Banking Malware Hides By Abusing Avast Executable. Retrieved May 26, 2020.
- Lancaster, T. (2018, November 5). Inception Attackers Target Europe with Year-old Office Vulnerability. Retrieved May 8, 2020.
- Mercer, W. et al. (2020, June 29). PROMETHIUM extends global reach with StrongPity3 APT. Retrieved July 20, 2020.
- Holland, A. (2019, March 7). Tricks and COMfoolery: How Ursnif Evades Detection. Retrieved June 10, 2019.
- Wardle, Patrick. (2018, December 20). Middle East Cyber-Espionage analyzing WindShift's implant: OSX.WindTail (part 1). Retrieved October 3, 2019.