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 legitimate utilities adversaries are capable of abusing, including both built-in binaries and tools such as PSExec, AutoHotKey, and IronPython.(Citation: LOLBAS Main Site)(Citation: Huntress Python Malware 2025)(Citation: The DFIR Report AutoHotKey 2023)(Citation: Splunk Detect Renamed PSExec) It may be possible to bypass those security mechanisms by renaming the utility prior to utilization (ex: rename <code>rundll32.exe</code>).(Citation: Elastic Masquerade Ball) An alternative case occurs when a legitimate utility is copied or moved to a different directory and renamed to avoid detections based on these utilities executing from non-standard paths.(Citation: F-Secure CozyDuke)
Renamed Legitimate Utility Execution with Metadata Mismatch and Suspicious Path
Restrict File and Directory Permissions: Restricting file and directory permissions involves setting access controls at the file system level to limit which users, groups, or processes can read, write, or execute files. By configuring permissions appropriately, organizations can reduce the attack surface for adversaries seeking to access sensitive data, plant malicious code, or tamper with system files.
Enforce Least Privilege Permissions:
Example (Windows): Right-click the shared folder → Properties → Security tab → Adjust permissions for NTFS ACLs.
Harden File Shares:
Example: Set permissions to restrict write access to critical files, such as system executables (e.g., /bin or /sbin on Linux). Use tools like chown and chmod to assign file ownership and limit access.
On Linux, apply:
chmod 750 /etc/sensitive.conf
chown root:admin /etc/sensitive.conf
File Integrity Monitoring (FIM):
Audit File System Access:
Restrict Startup Directories:
C:\ProgramData\Microsoft\Windows\Start Menu.Example: Restrict write access to critical directories like /etc/, /usr/local/, and Windows directories such as C:\Windows\System32.
icacls "C:\Windows\System32" /inheritance:r /grant:r SYSTEM:(OI)(CI)Flsattr or auditd.