Adversaries may attempt to manipulate features of their artifacts to make them appear legitimate or benign to users and/or security tools. Masquerading occurs when the name or location of an object, legitimate or malicious, is manipulated or abused for the sake of evading defenses and observation. This may include manipulating file metadata, tricking users into misidentifying the file type, and giving legitimate task or service names.
APT29 has set the hostnames of its C2 infrastructure to match legitimate hostnames in the victim environment. They have also used IP addresses originating from the same country as the victim for their VPN infrastructure.
Windshift has used icons mimicking MS Office files to mask malicious executables. Windshift has also attempted to hide executables by changing the file extension to ".scr" to mimic Windows screensavers.
Require signed binaries.
Use tools that restrict program execution via application control by attributes other than file name for common operating system utilities that are needed.
|M1022||Restrict File and Directory Permissions||
Use file system access controls to protect folders such as C:\Windows\System32.
|ID||Data Source||Data Component|
|DS0003||Scheduled Job||Scheduled Job Metadata|
|Scheduled Job Modification|
Collect file hashes; file names that do not match their expected hash are suspect. Perform file monitoring; files with known names but in unusual locations are suspect. Likewise, files that are modified outside of an update or patch are suspect.
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.
Look for indications of common characters that may indicate an attempt to trick users into misidentifying the file type, such as a space as the last character of a file name or the right-to-left override characters"\u202E", "[U+202E]", and "%E2%80%AE".