T1222.001 Windows File and Directory Permissions Modification

T1222.001 Windows File and Directory Permissions Modification

Sub-technique of: T1222

High-Level Description

Adversaries may modify file or directory permissions/attributes to evade access control lists (ACLs) and access protected files. File and directory permissions are commonly managed by ACLs configured by the file or directory owner, or users with the appropriate permissions. File and directory ACL implementations vary by platform, but generally explicitly designate which users or groups can perform which actions (read, write, execute, etc.).

Windows implements file and directory ACLs as Discretionary Access Control Lists (DACLs). Similar to a standard ACL, DACLs identifies the accounts that are allowed or denied access to a securable object. When an attempt is made to access a securable object, the system checks the access control entries in the DACL in order. If a matching entry is found, access to the object is granted. Otherwise, access is denied.

Adversaries can interact with the DACLs using built-in Windows commands, such as icacls, cacls, takeown, and attrib, which can grant adversaries higher permissions on specific files and folders. Further, PowerShell provides cmdlets that can be used to retrieve or modify file and directory DACLs. Specific file and directory modifications may be a required step for many techniques, such as establishing Persistence via Accessibility Features, Boot or Logon Initialization Scripts, or tainting/hijacking other instrumental binary/configuration files via Hijack Execution Flow.

Kill Chain Phase

• Defense Evasion (TA0005)

Platforms: Windows

What to Check

• Identify if Windows File and Directory Permissions Modification technique is applicable to target environment
• Check Windows systems for indicators of Windows File and Directory Permissions Modification
• Verify mitigations are bypassed or absent (2 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Atomic Red Team Tests

The following tests are from Atomic Red Team and provide actionable ways to test this technique:

Atomic Test 1: Take ownership using takeown utility

Modifies the filesystem permissions of the specified file or folder to take ownership of the object. Upon execution, "SUCCESS" will be displayed for the folder and each file inside of it.

Supported Platforms: windows

takeown.exe /f #{file_folder_to_own} /r