Masquerading: Rename System Utilities
Adversaries may rename legitimate system utilities to try to evade security mechanisms concerning the usage of those utilities. Security monitoring and control mechanisms may be in place for system utilities adversaries are capable of abusing.  It may be possible to bypass those security mechanisms by renaming the utility prior to utilization (ex: rename
rundll32.exe).  An alternative case occurs when a legitimate utility is copied or moved to a different directory and renamed to avoid detections based on system utilities executing from non-standard paths. 
The CozyCar dropper has masqueraded a copy of the infected system's rundll32.exe executable that was moved to the malware's install directory and renamed according to a predefined configuration file.
|M1022||Restrict File and Directory Permissions||
Use file system access controls to protect folders such as C:\Windows\System32.
If file names are mismatched between the file name on disk and that of the binary's PE metadata, this is a likely indicator that a binary was renamed after it was compiled. Collecting and comparing disk and resource filenames for binaries by looking to see if the InternalName, OriginalFilename, and/or ProductName match what is expected could provide useful leads, but may not always be indicative of malicious activity.  Do not focus on the possible names a file could have, but instead on the command-line arguments that are known to be used and are distinct because it will have a better rate of detection.
- LOLBAS. (n.d.). Living Off The Land Binaries and Scripts (and also Libraries). Retrieved February 10, 2020.
- Ewing, P. (2016, October 31). How to Hunt: The Masquerade Ball. Retrieved October 31, 2016.
- F-Secure Labs. (2015, April 22). CozyDuke: Malware Analysis. Retrieved December 10, 2015.
- Carr, N.. (2017, December 26). Nick Carr Status Update APT32 pubprn. Retrieved April 22, 2019.
- Cybereason Nocturnus. (2019, June 25). Operation Soft Cell: A Worldwide Campaign Against Telecommunications Providers. Retrieved July 18, 2019.
- Matsuda, A., Muhammad I. (2018, September 13). APT10 Targeting Japanese Corporations Using Updated TTPs. Retrieved September 17, 2018.
- Carr, N.. (2018, October 25). Nick Carr Status Update Masquerading. Retrieved April 22, 2019.